DOI: 10.1148/rg.233025122
(Radiographics. 2003;23:785-789.)
© RSNA, 2003
Best Cases from the AFIP
Involuted Sclerotic Meningioma1
Mark A. Shaman, MD,
Imad T. Zak, MD and
William J. Kupsky, MD
1 From the Department of Diagnostic Radiology, Division of Neuroradiology, Wayne State University School of Medicine, DRH 3L8, 4201 St Antoine, Detroit, MI 48201 (M.A.S., I.T.Z.); and the Department of Pathology, Wayne State University School of Medicine, Harper University Hospital, Detroit, Mich (W.J.K.). Received July 11, 2002; revision requested August 9 and received September 17; accepted September 18. Address correspondence to M.A.S. (e-mail: mshaman@med.wayne.edu).
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History
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A 27-year-old man presented to the emergency department with a 1-year history of intermittent, severe, sharp headache. The pain was usually generalized but on occasion was localized to the left side of the head and was sometimes associated with photophobia and sonophobia. The patient reported experiencing weakness and clumsiness of the left arm over the past year. The results of physical and neurologic examinations were normal. Computed tomography (CT) demonstrated a densely calcified mass, likely a meningioma, over the convexity of the left temporal lobe posteriorly. The clinical impression was that the headaches were related to migraines and not to the mass. The patient subsequently underwent magnetic resonance (MR) imaging, which helped confirm a densely calcified extraaxial mass.
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Imaging Findings
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Unenhanced CT of the brain demonstrated a 3-cm densely calcified mass abutting the posterior aspect of the left temporal lobe. The mass had not eroded the overlying calvaria, and there was no evidence of calvarial hyperostosis (Fig 1).
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Figure 1a. (a) Axial CT scan (window width = 80 HU, window level = 45 HU; 120 kV, 300 mAs) of the brain demonstrates a densely calcified, peripherally located 3-cm mass in the posterior aspect of the left temporal lobe. (b) Axial CT scan (window width = 3,500 HU, window level = 900 HU) demonstrates no erosion, hyperostosis, or scalloping of the overlying calvaria.
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Figure 1b. (a) Axial CT scan (window width = 80 HU, window level = 45 HU; 120 kV, 300 mAs) of the brain demonstrates a densely calcified, peripherally located 3-cm mass in the posterior aspect of the left temporal lobe. (b) Axial CT scan (window width = 3,500 HU, window level = 900 HU) demonstrates no erosion, hyperostosis, or scalloping of the overlying calvaria.
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Axial unenhanced MR imaging documented a 3 x 3 x 4-cm extraaxial tumor overlying the posterior and superior aspects of the left temporal lobe. This mass was heterogeneously hypointense at T1-weighted MR imaging (Fig 2a) and markedly hypointense at T2-weighted imaging (Fig 2b), findings that were consistent with the dense calcification seen at CT. A thin rim of hyperintensity compatible with vasogenic edema was seen anterior to the tumor in the adjacent brain parenchyma at T2-weighted imaging (Fig 2b). The mass showed mild focal curvilinear enhancement along its anterior margin after administration of gadolinium-based contrast material. There was no evidence of a dural tail (Fig 2c, 2d).
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Figure 2a. (a) Axial unenhanced T1-weighted MR image (repetition time [TR] msec/echo time [TE] msec = 570/17) demonstrates an extraaxial mass over the posterosuperior aspect of the left temporal lobe. The mass measured 3 x 3 x 4 cm and demonstrated low signal intensity with all sequences. (b) Axial T2-weighted MR image (3,700/90) demonstrates a thin margin of hyperintensity anterior to the tumor in the adjacent brain parenchyma. (c, d) Axial (c) and coronal (d) contrast-enhanced MR images (570/17) show mild focal enhancement along the anterior margin of the mass. There is no evidence of a dural tail.
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Figure 2b. (a) Axial unenhanced T1-weighted MR image (repetition time [TR] msec/echo time [TE] msec = 570/17) demonstrates an extraaxial mass over the posterosuperior aspect of the left temporal lobe. The mass measured 3 x 3 x 4 cm and demonstrated low signal intensity with all sequences. (b) Axial T2-weighted MR image (3,700/90) demonstrates a thin margin of hyperintensity anterior to the tumor in the adjacent brain parenchyma. (c, d) Axial (c) and coronal (d) contrast-enhanced MR images (570/17) show mild focal enhancement along the anterior margin of the mass. There is no evidence of a dural tail.
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Figure 2c. (a) Axial unenhanced T1-weighted MR image (repetition time [TR] msec/echo time [TE] msec = 570/17) demonstrates an extraaxial mass over the posterosuperior aspect of the left temporal lobe. The mass measured 3 x 3 x 4 cm and demonstrated low signal intensity with all sequences. (b) Axial T2-weighted MR image (3,700/90) demonstrates a thin margin of hyperintensity anterior to the tumor in the adjacent brain parenchyma. (c, d) Axial (c) and coronal (d) contrast-enhanced MR images (570/17) show mild focal enhancement along the anterior margin of the mass. There is no evidence of a dural tail.
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Figure 2d. (a) Axial unenhanced T1-weighted MR image (repetition time [TR] msec/echo time [TE] msec = 570/17) demonstrates an extraaxial mass over the posterosuperior aspect of the left temporal lobe. The mass measured 3 x 3 x 4 cm and demonstrated low signal intensity with all sequences. (b) Axial T2-weighted MR image (3,700/90) demonstrates a thin margin of hyperintensity anterior to the tumor in the adjacent brain parenchyma. (c, d) Axial (c) and coronal (d) contrast-enhanced MR images (570/17) show mild focal enhancement along the anterior margin of the mass. There is no evidence of a dural tail.
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Pathologic Evaluation
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The tumor was completely excised. The resected specimen consisted of an irregular, firm, bosselated, tan-white nodule measuring 3 x 2.8 x 2.5 cm and attached on one surface to a cuff of dura mater (Fig 3a). The bisected nodule appeared partly calcified and did not appear to penetrate the dural membrane (Fig 3b). The specimen was fixed in buffered 10% formaldehyde and decalcified. Paraffin-embedded sections were stained with hematoxylin-eosin (H-E) stain. The tumor consisted primarily of densely packed hyalinized collagen bundles (Fig 4a). Most areas were virtually acellular, but occasional small nests of cells were seen, often near the periphery of the tumor. The cell nests were composed of moderately small, generally uniform meningothelial-type cells (Fig 4b). In some areas, the collagen fibers were arranged in compact whorllike structures. Small blood vessels were occasionally seen, and irregular areas of calcification were identified. No atypical or anaplastic features were noted, and no central or peripheral nerve tissue was identified. These findings were consistent with an involuted sclerotic meningioma.
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Figure 3a. (a) Photograph of the resected specimen demonstrates a smooth-surface nodule that is attached to the dural membrane. (b) Photograph shows the bisected nodule to be partially calcified, with a white-tan fibrous appearance. The nodule does not appear to penetrate the dural membrane.
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Figure 3b. (a) Photograph of the resected specimen demonstrates a smooth-surface nodule that is attached to the dural membrane. (b) Photograph shows the bisected nodule to be partially calcified, with a white-tan fibrous appearance. The nodule does not appear to penetrate the dural membrane.
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Figure 4a. (a) Low-power photomicrograph (original magnification, x20; H-E stain) shows bundles of densely packed, cellular hyalinized collagen with a homogeneous appearance. Arrow indicates small nests of residual tumor cells. (b) High-power photomicrograph (original magnification, x1,000; H-E stain) of the cell nests shows uniform meningothelial cells embedded in collagen. No atypical features are seen.
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Figure 4b. (a) Low-power photomicrograph (original magnification, x20; H-E stain) shows bundles of densely packed, cellular hyalinized collagen with a homogeneous appearance. Arrow indicates small nests of residual tumor cells. (b) High-power photomicrograph (original magnification, x1,000; H-E stain) of the cell nests shows uniform meningothelial cells embedded in collagen. No atypical features are seen.
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Discussion
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The clinical, pathologic, surgical, and radiologic aspects of meningioma are important for several reasons: its relatively high prevalence, the high prevalence of focal signs and symptoms, and the fact that meningiomas often produce bone changes that can be readily detected and evaluated.
Meningiomas are the most common primary nonglial intracranial tumors (1). A large neurosurgical series from the United States and Europe reported that meningiomas account for 13%–19% of all surgically treated brain tumors (2). The occurrence rate of meningioma is likely even higher because many asymptomatic meningiomas are found incidentally at routine autopsy (3). A large autopsy series conducted over a 10-year period documented a prevalence of meningiomas of 1.44% (4). Meningiomas mostly affect people in the middle and later decades of life, with a 2:1 female predilection. In females, there are two peaks, the first occurring between 15 and 19 years of age, and the second occurring between 70 and 79 years of age. In males, the prevalence continues to increase until the 7th decade of life.
Atypical meningiomas are more common in children than in adults. Meningiomas account for 1.5%–3% of all intracranial tumors in children (5,6), are more likely to be malignant than those in adults, and are frequently associated with neurofibromatosis. In patients under 16 years old, meningiomas have been reported to occur more frequently in males (5). Hope et al (6) reported that 70% of the tumors in children are benign and have a favorable prognosis. Seven out of 15 benign meningiomas were of the sclerosing variety, four were of the "classic" meningothelial type, and four were transitional. Tumor invasion of the underlying cortex was reported in four of the seven sclerotic lesions, which may manifest clinically with seizures, and in one other lesion. Malignant meningioma and meningeal sarcoma accounted for 28% of all primary meningeal tumors in children (6). Darling et al (7) reported on the imaging of pediatric meningiomas and emphasized the large tumor size at presentation. These investigators reported the histologic and MR imaging findings in eight cases. At histologic analysis, four of these meningiomas were meningothelial, three were transitional, and one was sclerotic. The sclerotic meningioma was isointense relative to gray matter at T1-weighted MR imaging and markedly hypointense at T2-weighted imaging, whereas CT showed large calcifications (7).
The World Health Organization 2000 classification scheme recognizes three major groups of meningiomas. The first major group comprises the "variants" and includes meningothelial, fibrous (fibroblastic), transitional (mixed), psammomatous, angiomatous, microcystic, secretory, clear cell, chordoid, lymphoplasmacyte-rich, and metaplastic subtypes. The second major group consists of atypical meningiomas, and the third major group represents anaplastic (malignant) meningiomas. Metastatic lesions are extremely rare, with only 16 cases reported prior to 1989.
The fibroblastic potential of meningioma is well known. The typical fibrous meningioma shows parallel and interlacing bundles of spindle-like cells embedded in a matrix of collagen and reticulin. However, sclerotic meningiomas demonstrate whorl formation around sclerotic vessels, with tumor cells demonstrating glial fibrillary acidic protein expression (8). Sclerotic meningioma is a distinct subtype of benign meningioma that may lack the classic appearance and manifestation of typical meningothelial meningiomas. In classic meningothelial meningioma, CT typically shows a relatively hyperattenuating, broad based extraaxial mass with a smooth or lobulated outline that enhances homogeneously with contrast material administration. In the sclerotic variety, poor or partial enhancement is seen and calcification is more common (6). T2-weighted MR imaging demonstrates a mass with low signal intensity, which corresponds to the psammomatous calcification seen at histopathologic analysis (9).
Meningiomas have a distinct predilection for certain intracranial locations, although they may occur in any area where arachnoidal cap cells exist. There is usually a strong correlation between the location of the arachnoid granulations and the prevalent sites of origin for meningiomas (10). Meningiomas are typically broad based and firmly attached to the adjacent dura mater. Approximately 50% of convexity meningiomas are parasagittal or attached to the sagittal sinus. Other common sites include the dura mater adjacent to the anterior sylvian fissure, the sphenoid wings, the tuberculum sellae, the perisellar region, and the olfactory grooves. These lesions may also arise from the optic nerve sheath intraconally or extend into the optic foramen from a tuberculum sella tumor. In the posterior fossa, meningiomas frequently arise from the petrous bone in the cerebellopontine angle, the clivus, the tentorial leaf, and the tentorial free margin.
Rarely, meningiomas may be located in the depths of the sylvian fissure or may even be intraventricular. These rare intraventricular meningiomas are usually in the lateral ventricle but can manifest in the third and fourth ventricles. They arise from the arachnoidal cap cell rest within the stroma of the choroid plexus.
Multiplanar capability and exquisite contrast resolution are the main advantages of MR imaging in the accurate delineation and localization of a meningioma in the extraaxial compartment. Several imaging criteria help localize meningiomas as extracerebral and represent the key to diagnosis. The "dural tail sign," which is thought to represent a reactive process in the meninges or neoplastic infiltration of the dura mater (11), is characteristic but not specific. Hyperostosis or invasion of the adjacent bone is a highly specific finding for the extraaxial origin of meningioma, although it is infrequently present. The identification of various anatomic structures interposed between the tumor surface and the brain surface is another specific characteristic of extraaxial location. These anatomic structures are pial vascular structures, cerebrospinal fluid clefts, and dural margins. One or more of these interfaces can be identified in most cases (12). Pial blood vessel interfaces appear with all sequences as punctate, curvilinear signal voids at or along one or more tumor-brain interfaces. Cerebrospinal fluid clefts are identifiable at MR imaging in about 80% of meningiomas, appearing as high-signal-intensity clefts with long TR–long TE sequences and isointense relative to the adjacent tumor and brain with long TR–short TE sequences. The dural margin interface is seen primarily in meningiomas of the cavernous sinus, covering the lateral margin of the tumor and separating it from the adjacent temporal lobe. This interface appears as a low-signal-intensity rim with all imaging sequences.
Cerebral edema accompanying meningioma likely has multiple causes (13). Studies have indicated that the presence of edema correlates well with either the meningioma blood supply coming in some degree from cerebral pial arteries, or with its venous drainage into the cortical cerebral veins (14). Tumor infiltration into adjacent brain parenchyma is also thought to be a cause of cerebral edema (15). Although varying amounts of edema may be present with any of the meningioma cell types, fibroblastic and transitional cell tumors have been reported to have only mild to moderate degrees of edema. Severe edema tends to be associated with meningiomas of the syncytial or angioblastic cell type (9). Chen et al (16) found that aggressive meningiomas were more vascular, but that there was no correlation between the degree of surrounding edema or contrast enhancement and the histopathologic findings.
Differential diagnosis for classic meningioma should include metastasis, lymphoma, and inflammatory conditions such as sarcoidosis and tuberculosis (17). Differential diagnosis for an extraaxial calcified mass without dural or bone reaction (as in this case) should include osteoma, chronic epidural-subdural hematoma, and empyema.
The accepted treatment for meningioma is total resection. If complete tumor removal cannot be achieved, recurrence can be expected, requiring subsequent surgical extirpation. Radiation therapy has been advocated for cases in which surgery is not possible or is no longer feasible, especially in cases of suspected malignant meningioma (18). However, radiation has been implicated in the production of meningioma (19,20) and meningeal sarcoma.
The patient in this case has resumed a normal lifestyle and has had no recurrence of meningioma since he underwent surgery 18 months ago.
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Footnotes
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Editor’s Note.—Everyone who has taken the course in radiologic pathology at the Armed Forces Institute of Pathology (AFIP) remembers bringing two beautifully illustrated cases for accession to the Institute. In recent years, the staff of the Department of Radiologic Pathology has judged the "best cases" by organ system, and recognition is given to the winners on the last day of the class. With each issue of RadioGraphics, one or more of these cases are published, written by the winning resident. Radiologic-pathologic correlation is emphasized, and the causes of the imaging signs of various diseases are illustrated.
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References
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- Hardman JM. Non-glial tumors of the nervous system. In: Schochet SS, Jr, eds. Neuropathology. Vol 3 of Rosenberg RN, ed. The clinical neurosciences. New York, NY: Churchill Livingstone, 1983; 119.
- Grant FG. A study of the results of surgical treatment in 2,326 consecutive patients with brain tumor. J Neurosurg 1956; 13:479-488.[Medline]
- Wood MW, White RJ, Kernohan JW. One hundred intracranial meningiomas found incidentally at necropsy. J Neuropathol Exp Neurol 1957; 16:337-340.
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- Ferrante L, Acqui M, Mastronardi L, Rocchi G, Fortuna A. Cerebral meningiomas in children. Childs Nerv Syst 1989; 5:83-86.[CrossRef][Medline]
- Hope JK, Armstrong DA, Babyn PS, et al. Primary meningeal tumors in children: correlation of clinical and CT findings with histologic type and prognosis. AJNR Am J Neuroradiol 1992; 3:1353-1364.
- Darling CF, Byrd SE, Mugica M, et al. MR of pediatric meningiomas. AJNR Am J Neuroradiol 1994; 15:435-444.[Abstract]
- Haberler C, Jarius C, Lang S, et al. Fibrous meningeal tumors with extensive non-calcifying collagenous whorls and glial fibrillary acidic protein expression: the whirling-sclerosing variant of meningioma. Neuropathol Appl Neurobiol 2002; 28:42-47.[CrossRef][Medline]
- Elster AD, Challa VR, Gilbert TH, Richardson DN, Contento JC. Meningiomas: MR and histopathologic features. Radiology 1989; 170:857-862.[Abstract/Free Full Text]
- Russell DS, Rubinstein LJ. Pathology of tumors of the nervous system 5th ed. Baltimore, Md: Williams & Wilkins, 1989.
- Tokumaru A, O’uchi T, Eguchi T, et al. Prominent meningeal enhancement adjacent to meningioma on Gd-DTPA–enhanced MR images: histopathologic correlation. Radiology 1990; 175:431-433.[Abstract/Free Full Text]
- Spagnoli MV, Goldberg HI, Grossman RI, et al. Intracranial meningiomas: high-field MR imaging. Radiology 1986; 161:369-375.[Abstract/Free Full Text]
- Rohringer M, Sutherland G, Louw D, Sima A. Incidence and clinicopathological features of meningioma. J Neurosurg 1989; 71:665-672.[Medline]
- O’Moore PV, Goldberg HI, Gonatas N. Factors relating to meningioma brain edema. AJNR Am J Neuroradiol 1983; 4:1138.
- Tamiya T, Ono Y, Matsumoto K, Ohmoto T. Peritumoral brain edema in intracranial meningiomas: effects of radiological and histological factors. Neurosurgery 2001; 49:1046-1051; discussion 1051–1052.[CrossRef][Medline]
- Chen TC, Zee C, Miller CA, et al. Magnetic resonance imaging and pathological correlates of meningioma. Neurosurgery 1992; 31:1015-1022.[Medline]
- Murtagh R, Linden C. Neuroimaging of intracranial meningiomas. Neurosurg Clin N Am 1994; 5:217-233.[Medline]
- Fukji M, Kitamura S, Ohgami T, Takaki T, Kinoshita K. Radiosensitivity of meningioma: analysis of five cases of highly vascular meningioma treated by preoperative irradiation. Acta Neurochir (Wien) 1977; 36:47-60.[CrossRef]
- Bogdanowicz WM, Sachs E, Jr. The possible role of radiation in oncogenesis of meningioma. Surg Neurol 1974; 2:379-383.[Medline]
- Rubinstein AB, Shalit MN, Cohen ML, Zandbank U, Reichenthal E. Radiation-induced cerebral meningioma: a recognizable entity. J Neurosurg 1984; 61:966-971.[Medline]
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History
Imaging Findings
