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From the Archives of the AFIP

Medulloblastoma: A Comprehensive Review with Radiologic-Pathologic Correlation¹

¹ From the Departments of Radiologic Pathology (K.K.K.) and Neuropathology (E.J.R.), Armed Forces Institute of Pathology, 14th St at Alaska Ave, Bldg 54, Washington, DC 20306-6000; Departments of Radiology and Nuclear Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md (K.K.K.); and Department of Pathology, George Washington University, Washington, DC (E.J.R.). Received July 17, 2003; revision requested July 30 and received August 14; accepted August 15. Address correspondence to K.K.K. (e-mail: koeller@afip.osd.mil).

View larger version (140K): [in a new window]   Figure 1.  Medulloblastoma. Photograph of an autopsy specimen sectioned in the midline shows a fairly well-circumscribed mass (m) of the superior cerebellar vermis.

View larger version (181K): [in a new window]   Figure 2.  Classic medulloblastoma. Photomicrograph (original magnification, x400; hematoxylin-eosin stain) of a classic medulloblastoma reveals monomorphic sheets of closely apposed small cells with a high nuclear-cytoplasmic ratio, occasionally interrupted by neuroblastic rosettes (arrows).

View larger version (191K): [in a new window]   Figure 3.  Desmoplastic-nodular medulloblastoma. Photomicrograph (original magnification x400; hematoxylin-eosin stain) of a desmoplastic-nodular medulloblastoma shows a prominent nodule, or "pale island," (I) containing small, uniform neurocytic cells with abundant cytoplasm. Smaller pale islands surround the dominant nodule. The internodular zones often contain abundant reticulin and are populated by more atypical cells.

View larger version (203K): [in a new window]   Figure 4.  Large cell-anaplastic medulloblastoma. Photomicrograph (original magnification x400; hematoxylin-eosin stain) of a large cell-anaplastic medulloblastoma demonstrates characteristic cells with large nuclei containing prominent nucleoli (arrowheads), accompanied by conspicuous apoptosis and numerous mitoses.

View larger version (160K): [in a new window]   Figure 5a.  Medulloblastoma in a 6-year-old girl with a 10-day history of nausea and vomiting. (a) Axial CT image shows a heterogeneous hyperattenuated mass in the right cerebellar hemisphere. (b) On an axial T1-weighted MR image, the mass has homogeneous hypointensity compared with normal cerebellar signal intensity. (c) On an axial T2-weighted MR image, the mass is heterogeneous with surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement of the mass.

View larger version (146K): [in a new window]   Figure 5b.  Medulloblastoma in a 6-year-old girl with a 10-day history of nausea and vomiting. (a) Axial CT image shows a heterogeneous hyperattenuated mass in the right cerebellar hemisphere. (b) On an axial T1-weighted MR image, the mass has homogeneous hypointensity compared with normal cerebellar signal intensity. (c) On an axial T2-weighted MR image, the mass is heterogeneous with surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement of the mass.

View larger version (170K): [in a new window]   Figure 5c.  Medulloblastoma in a 6-year-old girl with a 10-day history of nausea and vomiting. (a) Axial CT image shows a heterogeneous hyperattenuated mass in the right cerebellar hemisphere. (b) On an axial T1-weighted MR image, the mass has homogeneous hypointensity compared with normal cerebellar signal intensity. (c) On an axial T2-weighted MR image, the mass is heterogeneous with surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement of the mass.

View larger version (161K): [in a new window]   Figure 5d.  Medulloblastoma in a 6-year-old girl with a 10-day history of nausea and vomiting. (a) Axial CT image shows a heterogeneous hyperattenuated mass in the right cerebellar hemisphere. (b) On an axial T1-weighted MR image, the mass has homogeneous hypointensity compared with normal cerebellar signal intensity. (c) On an axial T2-weighted MR image, the mass is heterogeneous with surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement of the mass.

View larger version (166K): [in a new window]   Figure 6a.  Medulloblastoma in a 3-year-old boy with a 1-month history of progressively worsening clumsiness, ataxia, headache, nausea, and vomiting. Developmental delay in speech and motor skills was also present. Papilledema was noted on physical examination. (a) Axial CT image shows a nearly homogeneous hyperattenuated mass in the posterior fossa midline. A thin crescent of the fourth ventricle (arrowheads) is noted along the anterior margin of the mass. (b) On an axial T1-weighted MR image, the mass is hypointense compared with the surrounding normal cerebellum. (c) On an axial T2-weighted MR image, the mass shows mild hyperintensity compared with surrounding normal brain tissue. (d) Contrast-enhanced axial T1-weighted MR image shows intense but mildly heterogeneous enhancement of the mass. (e) Photograph of the resected specimen highlights the soft friable nature of the mass, characteristic of a medulloblastoma.

View larger version (151K): [in a new window]   Figure 6b.  Medulloblastoma in a 3-year-old boy with a 1-month history of progressively worsening clumsiness, ataxia, headache, nausea, and vomiting. Developmental delay in speech and motor skills was also present. Papilledema was noted on physical examination. (a) Axial CT image shows a nearly homogeneous hyperattenuated mass in the posterior fossa midline. A thin crescent of the fourth ventricle (arrowheads) is noted along the anterior margin of the mass. (b) On an axial T1-weighted MR image, the mass is hypointense compared with the surrounding normal cerebellum. (c) On an axial T2-weighted MR image, the mass shows mild hyperintensity compared with surrounding normal brain tissue. (d) Contrast-enhanced axial T1-weighted MR image shows intense but mildly heterogeneous enhancement of the mass. (e) Photograph of the resected specimen highlights the soft friable nature of the mass, characteristic of a medulloblastoma.

View larger version (147K): [in a new window]   Figure 6c.  Medulloblastoma in a 3-year-old boy with a 1-month history of progressively worsening clumsiness, ataxia, headache, nausea, and vomiting. Developmental delay in speech and motor skills was also present. Papilledema was noted on physical examination. (a) Axial CT image shows a nearly homogeneous hyperattenuated mass in the posterior fossa midline. A thin crescent of the fourth ventricle (arrowheads) is noted along the anterior margin of the mass. (b) On an axial T1-weighted MR image, the mass is hypointense compared with the surrounding normal cerebellum. (c) On an axial T2-weighted MR image, the mass shows mild hyperintensity compared with surrounding normal brain tissue. (d) Contrast-enhanced axial T1-weighted MR image shows intense but mildly heterogeneous enhancement of the mass. (e) Photograph of the resected specimen highlights the soft friable nature of the mass, characteristic of a medulloblastoma.

View larger version (158K): [in a new window]   Figure 6d.  Medulloblastoma in a 3-year-old boy with a 1-month history of progressively worsening clumsiness, ataxia, headache, nausea, and vomiting. Developmental delay in speech and motor skills was also present. Papilledema was noted on physical examination. (a) Axial CT image shows a nearly homogeneous hyperattenuated mass in the posterior fossa midline. A thin crescent of the fourth ventricle (arrowheads) is noted along the anterior margin of the mass. (b) On an axial T1-weighted MR image, the mass is hypointense compared with the surrounding normal cerebellum. (c) On an axial T2-weighted MR image, the mass shows mild hyperintensity compared with surrounding normal brain tissue. (d) Contrast-enhanced axial T1-weighted MR image shows intense but mildly heterogeneous enhancement of the mass. (e) Photograph of the resected specimen highlights the soft friable nature of the mass, characteristic of a medulloblastoma.

View larger version (110K): [in a new window]   Figure 6e.  Medulloblastoma in a 3-year-old boy with a 1-month history of progressively worsening clumsiness, ataxia, headache, nausea, and vomiting. Developmental delay in speech and motor skills was also present. Papilledema was noted on physical examination. (a) Axial CT image shows a nearly homogeneous hyperattenuated mass in the posterior fossa midline. A thin crescent of the fourth ventricle (arrowheads) is noted along the anterior margin of the mass. (b) On an axial T1-weighted MR image, the mass is hypointense compared with the surrounding normal cerebellum. (c) On an axial T2-weighted MR image, the mass shows mild hyperintensity compared with surrounding normal brain tissue. (d) Contrast-enhanced axial T1-weighted MR image shows intense but mildly heterogeneous enhancement of the mass. (e) Photograph of the resected specimen highlights the soft friable nature of the mass, characteristic of a medulloblastoma.

View larger version (186K): [in a new window]   Figure 7a.  Medulloblastoma in a 4-year-old boy with a 2-week history of headaches and vomiting. (a) Axial CT image shows a heterogeneous mass in the posterior fossa midline. Soft-tissue portions are hyperattenuated whereas more cystlike areas are hypoattenuated. (b) On an axial T1-weighted MR image, the mass has similar heterogeneity. (c) Axial T2-weighted MR image demonstrates mild hyperintensity of the soft-tissue section and marked hyperintensity of the cystlike compartment. Note that the signal intensity of the cystlike portion (arrows) is even more intense than that of CSF, indicating that it is not simple fluid. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement within the soft-tissue segment.

View larger version (137K): [in a new window]   Figure 7b.  Medulloblastoma in a 4-year-old boy with a 2-week history of headaches and vomiting. (a) Axial CT image shows a heterogeneous mass in the posterior fossa midline. Soft-tissue portions are hyperattenuated whereas more cystlike areas are hypoattenuated. (b) On an axial T1-weighted MR image, the mass has similar heterogeneity. (c) Axial T2-weighted MR image demonstrates mild hyperintensity of the soft-tissue section and marked hyperintensity of the cystlike compartment. Note that the signal intensity of the cystlike portion (arrows) is even more intense than that of CSF, indicating that it is not simple fluid. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement within the soft-tissue segment.

View larger version (165K): [in a new window]   Figure 7c.  Medulloblastoma in a 4-year-old boy with a 2-week history of headaches and vomiting. (a) Axial CT image shows a heterogeneous mass in the posterior fossa midline. Soft-tissue portions are hyperattenuated whereas more cystlike areas are hypoattenuated. (b) On an axial T1-weighted MR image, the mass has similar heterogeneity. (c) Axial T2-weighted MR image demonstrates mild hyperintensity of the soft-tissue section and marked hyperintensity of the cystlike compartment. Note that the signal intensity of the cystlike portion (arrows) is even more intense than that of CSF, indicating that it is not simple fluid. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement within the soft-tissue segment.

View larger version (148K): [in a new window]   Figure 7d.  Medulloblastoma in a 4-year-old boy with a 2-week history of headaches and vomiting. (a) Axial CT image shows a heterogeneous mass in the posterior fossa midline. Soft-tissue portions are hyperattenuated whereas more cystlike areas are hypoattenuated. (b) On an axial T1-weighted MR image, the mass has similar heterogeneity. (c) Axial T2-weighted MR image demonstrates mild hyperintensity of the soft-tissue section and marked hyperintensity of the cystlike compartment. Note that the signal intensity of the cystlike portion (arrows) is even more intense than that of CSF, indicating that it is not simple fluid. (d) Contrast-enhanced axial T1-weighted MR image shows heterogeneous enhancement within the soft-tissue segment.

View larger version (157K): [in a new window]   Figure 8.  Medulloblastoma in a 10-year-old boy. Axial CT image shows a heterogeneous hyperattenuated mass in the midline of the posterior fossa. Focal areas of hyperattenuation (arrows) represent calcification, an occasional manifestation of this disease. (Reprinted, with permission, from reference 55.)

View larger version (164K): [in a new window]   Figure 9a.  Medulloblastoma in a 4-year-old boy with a 2-month history of ataxic gait. On day of admission, he hit his head on the floor and presented comatose to the emergency department. (a) Axial CT image shows a heterogeneous mass in the cerebellar vermis. Areas of hyperattenuation (arrowheads) are secondary to hemorrhage. The fourth ventricle is not seen. (b) Axial T1-weighted MR image shows mild hyperintensity in the hemorrhagic regions; otherwise the mass is predominantly hypointense. (c) Axial T2-weighted MR image reveals marked hypointensity in the hemorrhagic zones. These features are consistent with intracellular methemoglobin. (d) Contrast-enhanced axial T1-weighted MR image demonstrates heterogeneous but intense enhancement of the nonhemorrhagic portions. (e) Sagittal T1-weighted MR image shows complete filling of the fourth ventricle and upward extension of the posterior fossa mass through the cerebral aqueduct (arrow) into the third ventricle.

View larger version (179K): [in a new window]   Figure 9b.  Medulloblastoma in a 4-year-old boy with a 2-month history of ataxic gait. On day of admission, he hit his head on the floor and presented comatose to the emergency department. (a) Axial CT image shows a heterogeneous mass in the cerebellar vermis. Areas of hyperattenuation (arrowheads) are secondary to hemorrhage. The fourth ventricle is not seen. (b) Axial T1-weighted MR image shows mild hyperintensity in the hemorrhagic regions; otherwise the mass is predominantly hypointense. (c) Axial T2-weighted MR image reveals marked hypointensity in the hemorrhagic zones. These features are consistent with intracellular methemoglobin. (d) Contrast-enhanced axial T1-weighted MR image demonstrates heterogeneous but intense enhancement of the nonhemorrhagic portions. (e) Sagittal T1-weighted MR image shows complete filling of the fourth ventricle and upward extension of the posterior fossa mass through the cerebral aqueduct (arrow) into the third ventricle.

View larger version (175K): [in a new window]   Figure 9c.  Medulloblastoma in a 4-year-old boy with a 2-month history of ataxic gait. On day of admission, he hit his head on the floor and presented comatose to the emergency department. (a) Axial CT image shows a heterogeneous mass in the cerebellar vermis. Areas of hyperattenuation (arrowheads) are secondary to hemorrhage. The fourth ventricle is not seen. (b) Axial T1-weighted MR image shows mild hyperintensity in the hemorrhagic regions; otherwise the mass is predominantly hypointense. (c) Axial T2-weighted MR image reveals marked hypointensity in the hemorrhagic zones. These features are consistent with intracellular methemoglobin. (d) Contrast-enhanced axial T1-weighted MR image demonstrates heterogeneous but intense enhancement of the nonhemorrhagic portions. (e) Sagittal T1-weighted MR image shows complete filling of the fourth ventricle and upward extension of the posterior fossa mass through the cerebral aqueduct (arrow) into the third ventricle.

View larger version (178K): [in a new window]   Figure 9d.  Medulloblastoma in a 4-year-old boy with a 2-month history of ataxic gait. On day of admission, he hit his head on the floor and presented comatose to the emergency department. (a) Axial CT image shows a heterogeneous mass in the cerebellar vermis. Areas of hyperattenuation (arrowheads) are secondary to hemorrhage. The fourth ventricle is not seen. (b) Axial T1-weighted MR image shows mild hyperintensity in the hemorrhagic regions; otherwise the mass is predominantly hypointense. (c) Axial T2-weighted MR image reveals marked hypointensity in the hemorrhagic zones. These features are consistent with intracellular methemoglobin. (d) Contrast-enhanced axial T1-weighted MR image demonstrates heterogeneous but intense enhancement of the nonhemorrhagic portions. (e) Sagittal T1-weighted MR image shows complete filling of the fourth ventricle and upward extension of the posterior fossa mass through the cerebral aqueduct (arrow) into the third ventricle.

View larger version (152K): [in a new window]   Figure 9e.  Medulloblastoma in a 4-year-old boy with a 2-month history of ataxic gait. On day of admission, he hit his head on the floor and presented comatose to the emergency department. (a) Axial CT image shows a heterogeneous mass in the cerebellar vermis. Areas of hyperattenuation (arrowheads) are secondary to hemorrhage. The fourth ventricle is not seen. (b) Axial T1-weighted MR image shows mild hyperintensity in the hemorrhagic regions; otherwise the mass is predominantly hypointense. (c) Axial T2-weighted MR image reveals marked hypointensity in the hemorrhagic zones. These features are consistent with intracellular methemoglobin. (d) Contrast-enhanced axial T1-weighted MR image demonstrates heterogeneous but intense enhancement of the nonhemorrhagic portions. (e) Sagittal T1-weighted MR image shows complete filling of the fourth ventricle and upward extension of the posterior fossa mass through the cerebral aqueduct (arrow) into the third ventricle.

View larger version (172K): [in a new window]   Figure 10a.  Medulloblastoma in a 6-year-old boy with recurrent headaches. (a) Axial T1-weighted MR image shows a heterogeneous soft-tissue mass (arrows) in the right cerebellar hemisphere with an associated peripheral cystlike region. The soft-tissue portion is hypointense relative to the normal cerebellum. Several focal areas of fluidlike hypointensity are noted within the mass. (b) Axial T2-weighted MR image shows that the soft-tissue component is slightly hyperintense relative to the normal cerebellum. The fluidlike areas are again noted. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense but heterogeneous enhancement of the soft-tissue portion. The nonenhancing regions represent either cystic degeneration or necrosis.

View larger version (174K): [in a new window]   Figure 10b.  Medulloblastoma in a 6-year-old boy with recurrent headaches. (a) Axial T1-weighted MR image shows a heterogeneous soft-tissue mass (arrows) in the right cerebellar hemisphere with an associated peripheral cystlike region. The soft-tissue portion is hypointense relative to the normal cerebellum. Several focal areas of fluidlike hypointensity are noted within the mass. (b) Axial T2-weighted MR image shows that the soft-tissue component is slightly hyperintense relative to the normal cerebellum. The fluidlike areas are again noted. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense but heterogeneous enhancement of the soft-tissue portion. The nonenhancing regions represent either cystic degeneration or necrosis.

View larger version (167K): [in a new window]   Figure 10c.  Medulloblastoma in a 6-year-old boy with recurrent headaches. (a) Axial T1-weighted MR image shows a heterogeneous soft-tissue mass (arrows) in the right cerebellar hemisphere with an associated peripheral cystlike region. The soft-tissue portion is hypointense relative to the normal cerebellum. Several focal areas of fluidlike hypointensity are noted within the mass. (b) Axial T2-weighted MR image shows that the soft-tissue component is slightly hyperintense relative to the normal cerebellum. The fluidlike areas are again noted. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense but heterogeneous enhancement of the soft-tissue portion. The nonenhancing regions represent either cystic degeneration or necrosis.

View larger version (163K): [in a new window]   Figure 11a.  Medulloblastoma in a 4-month-old boy with irritability and vomiting. Physical examination revealed increased head circumference, bulging fontanelle, and left gaze preference. (a) Axial CT image shows a hyperattenuated heterogeneous mass in the midline of the posterior fossa with nearly complete effacement of adjacent cisternal spaces. (b) On an axial T1-weighted MR image, the mass is heterogeneous with focal areas of hyperintensity mixed with isointense signal. (c) On an axial T2-weighted MR image, the mass has mild hypointensity compared with gray matter and contains scattered areas of moderate hypointensity that correspond to regions of hemorrhage. (d) Contrast-enhanced sagittal MR image shows intense plaquelike enhancement of the mass with superior displacement of the straight sinus (arrowheads).

View larger version (159K): [in a new window]   Figure 11b.  Medulloblastoma in a 4-month-old boy with irritability and vomiting. Physical examination revealed increased head circumference, bulging fontanelle, and left gaze preference. (a) Axial CT image shows a hyperattenuated heterogeneous mass in the midline of the posterior fossa with nearly complete effacement of adjacent cisternal spaces. (b) On an axial T1-weighted MR image, the mass is heterogeneous with focal areas of hyperintensity mixed with isointense signal. (c) On an axial T2-weighted MR image, the mass has mild hypointensity compared with gray matter and contains scattered areas of moderate hypointensity that correspond to regions of hemorrhage. (d) Contrast-enhanced sagittal MR image shows intense plaquelike enhancement of the mass with superior displacement of the straight sinus (arrowheads).

View larger version (158K): [in a new window]   Figure 11c.  Medulloblastoma in a 4-month-old boy with irritability and vomiting. Physical examination revealed increased head circumference, bulging fontanelle, and left gaze preference. (a) Axial CT image shows a hyperattenuated heterogeneous mass in the midline of the posterior fossa with nearly complete effacement of adjacent cisternal spaces. (b) On an axial T1-weighted MR image, the mass is heterogeneous with focal areas of hyperintensity mixed with isointense signal. (c) On an axial T2-weighted MR image, the mass has mild hypointensity compared with gray matter and contains scattered areas of moderate hypointensity that correspond to regions of hemorrhage. (d) Contrast-enhanced sagittal MR image shows intense plaquelike enhancement of the mass with superior displacement of the straight sinus (arrowheads).

View larger version (174K): [in a new window]   Figure 11d.  Medulloblastoma in a 4-month-old boy with irritability and vomiting. Physical examination revealed increased head circumference, bulging fontanelle, and left gaze preference. (a) Axial CT image shows a hyperattenuated heterogeneous mass in the midline of the posterior fossa with nearly complete effacement of adjacent cisternal spaces. (b) On an axial T1-weighted MR image, the mass is heterogeneous with focal areas of hyperintensity mixed with isointense signal. (c) On an axial T2-weighted MR image, the mass has mild hypointensity compared with gray matter and contains scattered areas of moderate hypointensity that correspond to regions of hemorrhage. (d) Contrast-enhanced sagittal MR image shows intense plaquelike enhancement of the mass with superior displacement of the straight sinus (arrowheads).

View larger version (148K): [in a new window]   Figure 12a.  Medulloblastoma in a 10-month-old boy with nausea and vomiting for several months and recent onset of lethargy and failure to meet developmental milestones. (a) Axial CT image shows a heterogeneous mass involving the cerebellar vermis and hemisphere with extension toward the left cerebellopontine angle. The soft-tissue portion near midline is hyperattenuated, whereas the fluidlike compartment is more lateral and posterior in location. (b) Axial T1-weighted MR image reveals mild hypointensity of the soft-tissue portion with moderate hypointensity in the cystlike region. This latter signal intensity is more hyperintense relative to normal CSF, thereby indicating that it is not simple fluid but likely contains proteinaceous debris or possibly hemorrhage. The extension through the left foramen of Luschka (arrow) is better seen. (c) Axial T2-weighted MR image demonstrates heterogeneity within the soft-tissue portion. (d) Contrast-enhanced axial T1-weighted MR image shows peripheral rim enhancement of the cystlike portion and more solid enhancement within portions of the soft-tissue section. At surgery, the mass was seen to extend through the left foramen of Luschka.

View larger version (131K): [in a new window]   Figure 12b.  Medulloblastoma in a 10-month-old boy with nausea and vomiting for several months and recent onset of lethargy and failure to meet developmental milestones. (a) Axial CT image shows a heterogeneous mass involving the cerebellar vermis and hemisphere with extension toward the left cerebellopontine angle. The soft-tissue portion near midline is hyperattenuated, whereas the fluidlike compartment is more lateral and posterior in location. (b) Axial T1-weighted MR image reveals mild hypointensity of the soft-tissue portion with moderate hypointensity in the cystlike region. This latter signal intensity is more hyperintense relative to normal CSF, thereby indicating that it is not simple fluid but likely contains proteinaceous debris or possibly hemorrhage. The extension through the left foramen of Luschka (arrow) is better seen. (c) Axial T2-weighted MR image demonstrates heterogeneity within the soft-tissue portion. (d) Contrast-enhanced axial T1-weighted MR image shows peripheral rim enhancement of the cystlike portion and more solid enhancement within portions of the soft-tissue section. At surgery, the mass was seen to extend through the left foramen of Luschka.

View larger version (158K): [in a new window]   Figure 12c.  Medulloblastoma in a 10-month-old boy with nausea and vomiting for several months and recent onset of lethargy and failure to meet developmental milestones. (a) Axial CT image shows a heterogeneous mass involving the cerebellar vermis and hemisphere with extension toward the left cerebellopontine angle. The soft-tissue portion near midline is hyperattenuated, whereas the fluidlike compartment is more lateral and posterior in location. (b) Axial T1-weighted MR image reveals mild hypointensity of the soft-tissue portion with moderate hypointensity in the cystlike region. This latter signal intensity is more hyperintense relative to normal CSF, thereby indicating that it is not simple fluid but likely contains proteinaceous debris or possibly hemorrhage. The extension through the left foramen of Luschka (arrow) is better seen. (c) Axial T2-weighted MR image demonstrates heterogeneity within the soft-tissue portion. (d) Contrast-enhanced axial T1-weighted MR image shows peripheral rim enhancement of the cystlike portion and more solid enhancement within portions of the soft-tissue section. At surgery, the mass was seen to extend through the left foramen of Luschka.

View larger version (148K): [in a new window]   Figure 12d.  Medulloblastoma in a 10-month-old boy with nausea and vomiting for several months and recent onset of lethargy and failure to meet developmental milestones. (a) Axial CT image shows a heterogeneous mass involving the cerebellar vermis and hemisphere with extension toward the left cerebellopontine angle. The soft-tissue portion near midline is hyperattenuated, whereas the fluidlike compartment is more lateral and posterior in location. (b) Axial T1-weighted MR image reveals mild hypointensity of the soft-tissue portion with moderate hypointensity in the cystlike region. This latter signal intensity is more hyperintense relative to normal CSF, thereby indicating that it is not simple fluid but likely contains proteinaceous debris or possibly hemorrhage. The extension through the left foramen of Luschka (arrow) is better seen. (c) Axial T2-weighted MR image demonstrates heterogeneity within the soft-tissue portion. (d) Contrast-enhanced axial T1-weighted MR image shows peripheral rim enhancement of the cystlike portion and more solid enhancement within portions of the soft-tissue section. At surgery, the mass was seen to extend through the left foramen of Luschka.

View larger version (149K): [in a new window]   Figure 13a.  Medulloblastoma in a 3-year-old boy with a 1-week history of headache, vomiting, and difficulty walking at night. Papilledema was noted on physical examination. (a) Axial CT image shows a homogeneous hyperattenuated mass arising in the cerebellar vermis. A thin crescent of the fourth ventricle is visible along the ventral margin of the mass. (b) Axial T1-weighted MR image reveals the nearly homogeneous hypointense mass. Note a small focal area of marked hypointensity (arrowhead). (c) Axial T2-weighted MR image demonstrates diffuse hyperintensity of the mass and focal marked hyperintensity (arrowhead) of the area previously noted in b. This area represents either cystic change or necrosis. There is minimal surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows linear enhancement within the mass, but a large portion of it does not enhance.

View larger version (117K): [in a new window]   Figure 13b.  Medulloblastoma in a 3-year-old boy with a 1-week history of headache, vomiting, and difficulty walking at night. Papilledema was noted on physical examination. (a) Axial CT image shows a homogeneous hyperattenuated mass arising in the cerebellar vermis. A thin crescent of the fourth ventricle is visible along the ventral margin of the mass. (b) Axial T1-weighted MR image reveals the nearly homogeneous hypointense mass. Note a small focal area of marked hypointensity (arrowhead). (c) Axial T2-weighted MR image demonstrates diffuse hyperintensity of the mass and focal marked hyperintensity (arrowhead) of the area previously noted in b. This area represents either cystic change or necrosis. There is minimal surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows linear enhancement within the mass, but a large portion of it does not enhance.

View larger version (111K): [in a new window]   Figure 13c.  Medulloblastoma in a 3-year-old boy with a 1-week history of headache, vomiting, and difficulty walking at night. Papilledema was noted on physical examination. (a) Axial CT image shows a homogeneous hyperattenuated mass arising in the cerebellar vermis. A thin crescent of the fourth ventricle is visible along the ventral margin of the mass. (b) Axial T1-weighted MR image reveals the nearly homogeneous hypointense mass. Note a small focal area of marked hypointensity (arrowhead). (c) Axial T2-weighted MR image demonstrates diffuse hyperintensity of the mass and focal marked hyperintensity (arrowhead) of the area previously noted in b. This area represents either cystic change or necrosis. There is minimal surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows linear enhancement within the mass, but a large portion of it does not enhance.

View larger version (119K): [in a new window]   Figure 13d.  Medulloblastoma in a 3-year-old boy with a 1-week history of headache, vomiting, and difficulty walking at night. Papilledema was noted on physical examination. (a) Axial CT image shows a homogeneous hyperattenuated mass arising in the cerebellar vermis. A thin crescent of the fourth ventricle is visible along the ventral margin of the mass. (b) Axial T1-weighted MR image reveals the nearly homogeneous hypointense mass. Note a small focal area of marked hypointensity (arrowhead). (c) Axial T2-weighted MR image demonstrates diffuse hyperintensity of the mass and focal marked hyperintensity (arrowhead) of the area previously noted in b. This area represents either cystic change or necrosis. There is minimal surrounding vasogenic edema. (d) Contrast-enhanced axial T1-weighted MR image shows linear enhancement within the mass, but a large portion of it does not enhance.

View larger version (161K): [in a new window]   Figure 14a.  Medulloblastoma in a 33-year-old man with a 6-month history of headache and 2-week history of ataxia, vertigo, and vomiting. (a) Axial T1-weighted MR image shows predominantly hypointense masses that involve both cerebellar hemispheres. There is an ill-defined area (arrows) of nearly isointense signal along the posterior margin of the left cerebellar mass. Linear areas that are isointense (arrowheads) relative to normal cerebellar tissue are noted along the ventral margin of the left hemispheric mass. These areas bear some resemblance to the "striated" pattern seen in dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease), with the exception that the axis is perpendicular to that typically seen in the latter disease. (b) Axial T2-weighted MR image reveals predominant hyperintensity of the masses. An area of mild hypointensity suggestive of soft tissue can be seen along posterior margin of left hemispheric mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portion.

View larger version (170K): [in a new window]   Figure 14b.  Medulloblastoma in a 33-year-old man with a 6-month history of headache and 2-week history of ataxia, vertigo, and vomiting. (a) Axial T1-weighted MR image shows predominantly hypointense masses that involve both cerebellar hemispheres. There is an ill-defined area (arrows) of nearly isointense signal along the posterior margin of the left cerebellar mass. Linear areas that are isointense (arrowheads) relative to normal cerebellar tissue are noted along the ventral margin of the left hemispheric mass. These areas bear some resemblance to the "striated" pattern seen in dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease), with the exception that the axis is perpendicular to that typically seen in the latter disease. (b) Axial T2-weighted MR image reveals predominant hyperintensity of the masses. An area of mild hypointensity suggestive of soft tissue can be seen along posterior margin of left hemispheric mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portion.

View larger version (160K): [in a new window]   Figure 14c.  Medulloblastoma in a 33-year-old man with a 6-month history of headache and 2-week history of ataxia, vertigo, and vomiting. (a) Axial T1-weighted MR image shows predominantly hypointense masses that involve both cerebellar hemispheres. There is an ill-defined area (arrows) of nearly isointense signal along the posterior margin of the left cerebellar mass. Linear areas that are isointense (arrowheads) relative to normal cerebellar tissue are noted along the ventral margin of the left hemispheric mass. These areas bear some resemblance to the "striated" pattern seen in dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease), with the exception that the axis is perpendicular to that typically seen in the latter disease. (b) Axial T2-weighted MR image reveals predominant hyperintensity of the masses. An area of mild hypointensity suggestive of soft tissue can be seen along posterior margin of left hemispheric mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portion.

View larger version (186K): [in a new window]   Figure 15a.  Medulloblastoma in a 37-year-old man with a 1-month history of progressively severe headaches and episodes of dizziness. (a) Axial T2-weighted MR image shows hyperintense cerebellar masses (arrows) within both hemispheres. (b) Contrast-enhanced axial T1-weighted MR image reveals mild enhancement of the right cerebellar mass and subtle enhancement of the left cerebellar mass.

View larger version (128K): [in a new window]   Figure 15b.  Medulloblastoma in a 37-year-old man with a 1-month history of progressively severe headaches and episodes of dizziness. (a) Axial T2-weighted MR image shows hyperintense cerebellar masses (arrows) within both hemispheres. (b) Contrast-enhanced axial T1-weighted MR image reveals mild enhancement of the right cerebellar mass and subtle enhancement of the left cerebellar mass.

View larger version (135K): [in a new window]   Figure 16a.  Leptomeningeal metastatic spread from medulloblastoma in a 4-year-old boy with decreased level of consciousness and new onset of seizures. (a) Axial T2-weighted MR image shows ill-defined mild hyperintensity of the sulcal spaces bilaterally and hyperintensity within the corona radiata and external capsule region. (b) Contrast-enhanced axial T1-weighted MR image reveals diffuse bilateral leptomeningeal enhancement. (c) Contrast-enhanced coronal T1-weighted MR image shows similar features with more involvement on the right side than the left side. (d) Photograph of the brain sliced in the coronal plane correlates with the findings in c. Extensive leptomeningeal spread is evident (arrowheads).

View larger version (128K): [in a new window]   Figure 16b.  Leptomeningeal metastatic spread from medulloblastoma in a 4-year-old boy with decreased level of consciousness and new onset of seizures. (a) Axial T2-weighted MR image shows ill-defined mild hyperintensity of the sulcal spaces bilaterally and hyperintensity within the corona radiata and external capsule region. (b) Contrast-enhanced axial T1-weighted MR image reveals diffuse bilateral leptomeningeal enhancement. (c) Contrast-enhanced coronal T1-weighted MR image shows similar features with more involvement on the right side than the left side. (d) Photograph of the brain sliced in the coronal plane correlates with the findings in c. Extensive leptomeningeal spread is evident (arrowheads).

View larger version (175K): [in a new window]   Figure 16c.  Leptomeningeal metastatic spread from medulloblastoma in a 4-year-old boy with decreased level of consciousness and new onset of seizures. (a) Axial T2-weighted MR image shows ill-defined mild hyperintensity of the sulcal spaces bilaterally and hyperintensity within the corona radiata and external capsule region. (b) Contrast-enhanced axial T1-weighted MR image reveals diffuse bilateral leptomeningeal enhancement. (c) Contrast-enhanced coronal T1-weighted MR image shows similar features with more involvement on the right side than the left side. (d) Photograph of the brain sliced in the coronal plane correlates with the findings in c. Extensive leptomeningeal spread is evident (arrowheads).

View larger version (148K): [in a new window]   Figure 16d.  Leptomeningeal metastatic spread from medulloblastoma in a 4-year-old boy with decreased level of consciousness and new onset of seizures. (a) Axial T2-weighted MR image shows ill-defined mild hyperintensity of the sulcal spaces bilaterally and hyperintensity within the corona radiata and external capsule region. (b) Contrast-enhanced axial T1-weighted MR image reveals diffuse bilateral leptomeningeal enhancement. (c) Contrast-enhanced coronal T1-weighted MR image shows similar features with more involvement on the right side than the left side. (d) Photograph of the brain sliced in the coronal plane correlates with the findings in c. Extensive leptomeningeal spread is evident (arrowheads).

View larger version (125K): [in a new window]   Figure 17a.  Leptomeningeal metastatic spread from medulloblastoma in a 3-year-old boy with lethargy, malaise, weight loss, headache, nausea, and vomiting of several weeks’ duration. (a) Contrast-enhanced sagittal T1-weighted MR image shows intense enhancement of a mass arising in the cerebellar vermis. Diffuse leptomeningeal enhancement (arrowheads) is also noted along the ventral margin of the brain stem and upper cervical spinal cord. (b) Contrast-enhanced sagittal T1-weighted MR image reveals thin linear enhancement (arrowheads) along the margin of the thoracolumbar spinal cord to the tip of the conus medullaris. Note also the focal collection of enhancement (arrow) in the distal margin of the thecal sac.

View larger version (119K): [in a new window]   Figure 17b.  Leptomeningeal metastatic spread from medulloblastoma in a 3-year-old boy with lethargy, malaise, weight loss, headache, nausea, and vomiting of several weeks’ duration. (a) Contrast-enhanced sagittal T1-weighted MR image shows intense enhancement of a mass arising in the cerebellar vermis. Diffuse leptomeningeal enhancement (arrowheads) is also noted along the ventral margin of the brain stem and upper cervical spinal cord. (b) Contrast-enhanced sagittal T1-weighted MR image reveals thin linear enhancement (arrowheads) along the margin of the thoracolumbar spinal cord to the tip of the conus medullaris. Note also the focal collection of enhancement (arrow) in the distal margin of the thecal sac.

View larger version (139K): [in a new window]   Figure 18a.  Medulloblastoma in a 13-year-old girl with nausea, vomiting, nystagmus, and ataxia. Physical examination revealed bilateral papilledema. (a) Axial T1-weighted MR image shows a heterogeneous mass within the left cerebellar hemisphere. The mass appears to extend to the surface of the cerebellum. (b) Axial T2-weighted MR image reveals marked heterogeneity within the mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portions of the mass. (d) Contrast-enhanced coronal T1-weighted MR image shows exophytic extension (arrow) of the mass into the cerebellopontine angle. Ten months after surgical resection, the patient developed a single sacral metastasis (not shown). Despite radiation therapy, she developed neck and back pain 19 months later. (e) Postlaminectomy sagittal T2-weighted MR image shows multiple areas of abnormal hyperintensity (arrowheads) involving several cervical and thoracic vertebrae, indicative of metastatic disease. (f) Bone scan obtained 1 month later reveals diffuse increased uptake in the entire cervical spine and skull base as well as the humeral head.

View larger version (150K): [in a new window]   Figure 18b.  Medulloblastoma in a 13-year-old girl with nausea, vomiting, nystagmus, and ataxia. Physical examination revealed bilateral papilledema. (a) Axial T1-weighted MR image shows a heterogeneous mass within the left cerebellar hemisphere. The mass appears to extend to the surface of the cerebellum. (b) Axial T2-weighted MR image reveals marked heterogeneity within the mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portions of the mass. (d) Contrast-enhanced coronal T1-weighted MR image shows exophytic extension (arrow) of the mass into the cerebellopontine angle. Ten months after surgical resection, the patient developed a single sacral metastasis (not shown). Despite radiation therapy, she developed neck and back pain 19 months later. (e) Postlaminectomy sagittal T2-weighted MR image shows multiple areas of abnormal hyperintensity (arrowheads) involving several cervical and thoracic vertebrae, indicative of metastatic disease. (f) Bone scan obtained 1 month later reveals diffuse increased uptake in the entire cervical spine and skull base as well as the humeral head.

View larger version (145K): [in a new window]   Figure 18c.  Medulloblastoma in a 13-year-old girl with nausea, vomiting, nystagmus, and ataxia. Physical examination revealed bilateral papilledema. (a) Axial T1-weighted MR image shows a heterogeneous mass within the left cerebellar hemisphere. The mass appears to extend to the surface of the cerebellum. (b) Axial T2-weighted MR image reveals marked heterogeneity within the mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portions of the mass. (d) Contrast-enhanced coronal T1-weighted MR image shows exophytic extension (arrow) of the mass into the cerebellopontine angle. Ten months after surgical resection, the patient developed a single sacral metastasis (not shown). Despite radiation therapy, she developed neck and back pain 19 months later. (e) Postlaminectomy sagittal T2-weighted MR image shows multiple areas of abnormal hyperintensity (arrowheads) involving several cervical and thoracic vertebrae, indicative of metastatic disease. (f) Bone scan obtained 1 month later reveals diffuse increased uptake in the entire cervical spine and skull base as well as the humeral head.

View larger version (146K): [in a new window]   Figure 18d.  Medulloblastoma in a 13-year-old girl with nausea, vomiting, nystagmus, and ataxia. Physical examination revealed bilateral papilledema. (a) Axial T1-weighted MR image shows a heterogeneous mass within the left cerebellar hemisphere. The mass appears to extend to the surface of the cerebellum. (b) Axial T2-weighted MR image reveals marked heterogeneity within the mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portions of the mass. (d) Contrast-enhanced coronal T1-weighted MR image shows exophytic extension (arrow) of the mass into the cerebellopontine angle. Ten months after surgical resection, the patient developed a single sacral metastasis (not shown). Despite radiation therapy, she developed neck and back pain 19 months later. (e) Postlaminectomy sagittal T2-weighted MR image shows multiple areas of abnormal hyperintensity (arrowheads) involving several cervical and thoracic vertebrae, indicative of metastatic disease. (f) Bone scan obtained 1 month later reveals diffuse increased uptake in the entire cervical spine and skull base as well as the humeral head.

View larger version (151K): [in a new window]   Figure 18e.  Medulloblastoma in a 13-year-old girl with nausea, vomiting, nystagmus, and ataxia. Physical examination revealed bilateral papilledema. (a) Axial T1-weighted MR image shows a heterogeneous mass within the left cerebellar hemisphere. The mass appears to extend to the surface of the cerebellum. (b) Axial T2-weighted MR image reveals marked heterogeneity within the mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portions of the mass. (d) Contrast-enhanced coronal T1-weighted MR image shows exophytic extension (arrow) of the mass into the cerebellopontine angle. Ten months after surgical resection, the patient developed a single sacral metastasis (not shown). Despite radiation therapy, she developed neck and back pain 19 months later. (e) Postlaminectomy sagittal T2-weighted MR image shows multiple areas of abnormal hyperintensity (arrowheads) involving several cervical and thoracic vertebrae, indicative of metastatic disease. (f) Bone scan obtained 1 month later reveals diffuse increased uptake in the entire cervical spine and skull base as well as the humeral head.

View larger version (103K): [in a new window]   Figure 18f.  Medulloblastoma in a 13-year-old girl with nausea, vomiting, nystagmus, and ataxia. Physical examination revealed bilateral papilledema. (a) Axial T1-weighted MR image shows a heterogeneous mass within the left cerebellar hemisphere. The mass appears to extend to the surface of the cerebellum. (b) Axial T2-weighted MR image reveals marked heterogeneity within the mass. (c) Contrast-enhanced axial T1-weighted MR image demonstrates intense enhancement of the soft-tissue portions of the mass. (d) Contrast-enhanced coronal T1-weighted MR image shows exophytic extension (arrow) of the mass into the cerebellopontine angle. Ten months after surgical resection, the patient developed a single sacral metastasis (not shown). Despite radiation therapy, she developed neck and back pain 19 months later. (e) Postlaminectomy sagittal T2-weighted MR image shows multiple areas of abnormal hyperintensity (arrowheads) involving several cervical and thoracic vertebrae, indicative of metastatic disease. (f) Bone scan obtained 1 month later reveals diffuse increased uptake in the entire cervical spine and skull base as well as the humeral head.