DOI: 10.1148/rg.231025037
Primary Retroperitoneal Neoplasms: CT and MR Imaging Findings with Anatomic and Pathologic Diagnostic Clues1
Mizuki Nishino, MD,
Katsumi Hayakawa, MD,
Manabu Minami, MD,
Akira Yamamoto, MD,
Hiroyuki Ueda, MD and
Kosho Takasu, MD
1 From the Departments of Radiology (M.N., K.H.) and Pathology (K.T.), Kyoto City Hospital, 1-2 Higashi-takada-cho, Mibu, Nakagyo-ku, Kyoto 604-8845, Japan; the Department of Radiology, University of Tokyo, Japan (M.M.); and the Departments of Nuclear Medicine and Diagnostic Imaging, Graduate School of Medicine, Kyoto University, Kyoto, Japan (A.Y., H.U.). Presented as an education exhibit at the 2001 RSNA scientific assembly. Received February 26, 2002; revision requested April 26 and received May 21; accepted May 30. Address correspondence to M.N. (e-mail: mizuki@mbox.kyoto-inet.or.jp).
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Figure 1. Anterior displacement of the ascending colon. Computed tomographic (CT) scan shows a bulky mass that is difficult to localize at first glance. However, anterior displacement of the ascending colon (arrow) confirms that the mass is in the retroperitoneal space. The mass proved to be liposarcoma.
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Figure 2. Anterior displacement of the aorta. Axial T2-weighted magnetic resonance (MR) image of the abdomen shows a homogeneous, hypointense mass that surrounds the aorta and displaces it anteriorly. The mass proved to be lymphoma.
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Figure 3a. Anterior displacement of the inferior mesenteric vein. (a) Transverse contrast material-enhanced CT scan shows a well-defined enhancing mass that is posterior to the pancreas but lacks the mass effect to compress adjacent major organs. (b) CT scan shows anterior displacement of the inferior mesenteric vein (arrow), a finding that confirms that the mass is located in the retroperitoneum. The mass proved to be capillary hemangioma.
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Figure 3b. Anterior displacement of the inferior mesenteric vein. (a) Transverse contrast material-enhanced CT scan shows a well-defined enhancing mass that is posterior to the pancreas but lacks the mass effect to compress adjacent major organs. (b) CT scan shows anterior displacement of the inferior mesenteric vein (arrow), a finding that confirms that the mass is located in the retroperitoneum. The mass proved to be capillary hemangioma.
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Figure 4a. Beak sign. (a, b) Drawings illustrate the positive beak sign (a), in which Tumor A arises from Organ B, and the negative beak sign (b), in which Tumor A does not arise from Organ B. (c) Transverse contrast-enhanced CT scan shows a huge cystic tumor with the beak sign (arrow) in its contact surface with the pancreas. This finding represents mucinous cystadenocarcinoma of the pancreas.
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Figure 4b. Beak sign. (a, b) Drawings illustrate the positive beak sign (a), in which Tumor A arises from Organ B, and the negative beak sign (b), in which Tumor A does not arise from Organ B. (c) Transverse contrast-enhanced CT scan shows a huge cystic tumor with the beak sign (arrow) in its contact surface with the pancreas. This finding represents mucinous cystadenocarcinoma of the pancreas.
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Figure 4c. Beak sign. (a, b) Drawings illustrate the positive beak sign (a), in which Tumor A arises from Organ B, and the negative beak sign (b), in which Tumor A does not arise from Organ B. (c) Transverse contrast-enhanced CT scan shows a huge cystic tumor with the beak sign (arrow) in its contact surface with the pancreas. This finding represents mucinous cystadenocarcinoma of the pancreas.
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Figure 5a. Embedded organ sign. (a, b) Drawings illustrate the negative embedded organ sign (a), in which Tumor A simply compresses Organ B, and the positive embedded organ sign (b), in which Tumor A arises from Organ B so that the organ appears to be embedded in the tumor. (c) CT scan shows a huge heterogeneous mass. The lumen of the duodenum is stretched toward the mass, and the wall of the duodenum appears embedded in the mass at the contact surface (arrow). These findings represent gastrointestinal stromal tumor of the duodenum with a positive embedded organ sign. (Fig 5c courtesy of K. Togashi, MD, Department of Diagnostic and Interventional Imageology, Kyoto University, Kyoto, Japan.)
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Figure 5b. Embedded organ sign. (a, b) Drawings illustrate the negative embedded organ sign (a), in which Tumor A simply compresses Organ B, and the positive embedded organ sign (b), in which Tumor A arises from Organ B so that the organ appears to be embedded in the tumor. (c) CT scan shows a huge heterogeneous mass. The lumen of the duodenum is stretched toward the mass, and the wall of the duodenum appears embedded in the mass at the contact surface (arrow). These findings represent gastrointestinal stromal tumor of the duodenum with a positive embedded organ sign. (Fig 5c courtesy of K. Togashi, MD, Department of Diagnostic and Interventional Imageology, Kyoto University, Kyoto, Japan.)
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Figure 5c. Embedded organ sign. (a, b) Drawings illustrate the negative embedded organ sign (a), in which Tumor A simply compresses Organ B, and the positive embedded organ sign (b), in which Tumor A arises from Organ B so that the organ appears to be embedded in the tumor. (c) CT scan shows a huge heterogeneous mass. The lumen of the duodenum is stretched toward the mass, and the wall of the duodenum appears embedded in the mass at the contact surface (arrow). These findings represent gastrointestinal stromal tumor of the duodenum with a positive embedded organ sign. (Fig 5c courtesy of K. Togashi, MD, Department of Diagnostic and Interventional Imageology, Kyoto University, Kyoto, Japan.)
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Figure 6a. Lymphangioma in a 47-year-old woman. (a, b) Transverse contrast-enhanced abdominal (a) and pelvic (b) CT scans show a multiloculated, low-attenuation cystic mass that extends between normal anatomic structures in the peritoneal cavity and retroperitoneum. (c) Postoperative photograph shows the multiloculated cystic mass. Surgery revealed that the mass extended around the transverse mesocolon, the pancreas, and the posterior wall of the cecum and contained chylous fluid. (d) Photomicrograph (original magnification, x100; hematoxylin-eosin [H-E] stain) of the mass demonstrates endothelium-lined cavities.
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Figure 6b. Lymphangioma in a 47-year-old woman. (a, b) Transverse contrast-enhanced abdominal (a) and pelvic (b) CT scans show a multiloculated, low-attenuation cystic mass that extends between normal anatomic structures in the peritoneal cavity and retroperitoneum. (c) Postoperative photograph shows the multiloculated cystic mass. Surgery revealed that the mass extended around the transverse mesocolon, the pancreas, and the posterior wall of the cecum and contained chylous fluid. (d) Photomicrograph (original magnification, x100; hematoxylin-eosin [H-E] stain) of the mass demonstrates endothelium-lined cavities.
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Figure 6c. Lymphangioma in a 47-year-old woman. (a, b) Transverse contrast-enhanced abdominal (a) and pelvic (b) CT scans show a multiloculated, low-attenuation cystic mass that extends between normal anatomic structures in the peritoneal cavity and retroperitoneum. (c) Postoperative photograph shows the multiloculated cystic mass. Surgery revealed that the mass extended around the transverse mesocolon, the pancreas, and the posterior wall of the cecum and contained chylous fluid. (d) Photomicrograph (original magnification, x100; hematoxylin-eosin [H-E] stain) of the mass demonstrates endothelium-lined cavities.
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Figure 6d. Lymphangioma in a 47-year-old woman. (a, b) Transverse contrast-enhanced abdominal (a) and pelvic (b) CT scans show a multiloculated, low-attenuation cystic mass that extends between normal anatomic structures in the peritoneal cavity and retroperitoneum. (c) Postoperative photograph shows the multiloculated cystic mass. Surgery revealed that the mass extended around the transverse mesocolon, the pancreas, and the posterior wall of the cecum and contained chylous fluid. (d) Photomicrograph (original magnification, x100; hematoxylin-eosin [H-E] stain) of the mass demonstrates endothelium-lined cavities.
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Figure 7. Lymphoma in a 72-year-old woman. On a transverse contrast-enhanced CT scan, a homogeneous mass with minimal enhancement is noted around the aorta. Contrast-enhanced vessels are seen to penetrate the mass. Histologic analysis revealed B- cell lymphoma.
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Figure 8a. Lipoma. (a) Abdominal radiograph shows a huge radiolucent mass. (b) Transverse CT scan of the abdomen shows that the mass is composed primarily of fat. (c) On a T1-weighted MR image, the mass has homogeneous high signal intensity and compresses the kidney upward.
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Figure 8b. Lipoma. (a) Abdominal radiograph shows a huge radiolucent mass. (b) Transverse CT scan of the abdomen shows that the mass is composed primarily of fat. (c) On a T1-weighted MR image, the mass has homogeneous high signal intensity and compresses the kidney upward.
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Figure 8c. Lipoma. (a) Abdominal radiograph shows a huge radiolucent mass. (b) Transverse CT scan of the abdomen shows that the mass is composed primarily of fat. (c) On a T1-weighted MR image, the mass has homogeneous high signal intensity and compresses the kidney upward.
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Figure 9a. Well-differentiated liposarcoma in a 49-year-old woman. (a) Transverse contrast-enhanced CT scan demonstrates a huge heterogeneous mass with predominantly fat attenuation. (b) On a T1-weighted MR image, the mass has heterogeneous hyperintensity and a partly nodular appearance.
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Figure 9b. Well-differentiated liposarcoma in a 49-year-old woman. (a) Transverse contrast-enhanced CT scan demonstrates a huge heterogeneous mass with predominantly fat attenuation. (b) On a T1-weighted MR image, the mass has heterogeneous hyperintensity and a partly nodular appearance.
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Figure 10a. Mature cystic teratoma in a female infant. (a) Transverse CT scan of the abdomen shows a fat-containing cystic mass with calcifications. A diagnosis of mature teratoma was suggested preoperatively. (b) Coronal T1-weighted MR image shows that the left kidney is displaced downward into the pelvis. The kidney is clearly separate from the tumor.
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Figure 10b. Mature cystic teratoma in a female infant. (a) Transverse CT scan of the abdomen shows a fat-containing cystic mass with calcifications. A diagnosis of mature teratoma was suggested preoperatively. (b) Coronal T1-weighted MR image shows that the left kidney is displaced downward into the pelvis. The kidney is clearly separate from the tumor.
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Figure 11a. Schwannoma in a 70-year-old man. (a) Transverse contrast-enhanced CT scan shows a well-marginated low-attenuation mass interposed between the portal vein, superior mesenteric artery, aorta, and inferior vena cava. (b) On a T2-weighted MR image, the mass appears mostly hyperintense. (c) Photograph of the bisected gross specimen shows that the tumor is smoothly encapsulated and contains myxoid stroma. (d) Low-power photomicrograph (original magnification, x40; H-E stain) shows proliferation of fascicular interlacing spindle cells that resemble peripheral nerve tissue, along with loose fibrous stroma.
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Figure 11b. Schwannoma in a 70-year-old man. (a) Transverse contrast-enhanced CT scan shows a well-marginated low-attenuation mass interposed between the portal vein, superior mesenteric artery, aorta, and inferior vena cava. (b) On a T2-weighted MR image, the mass appears mostly hyperintense. (c) Photograph of the bisected gross specimen shows that the tumor is smoothly encapsulated and contains myxoid stroma. (d) Low-power photomicrograph (original magnification, x40; H-E stain) shows proliferation of fascicular interlacing spindle cells that resemble peripheral nerve tissue, along with loose fibrous stroma.
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Figure 11c. Schwannoma in a 70-year-old man. (a) Transverse contrast-enhanced CT scan shows a well-marginated low-attenuation mass interposed between the portal vein, superior mesenteric artery, aorta, and inferior vena cava. (b) On a T2-weighted MR image, the mass appears mostly hyperintense. (c) Photograph of the bisected gross specimen shows that the tumor is smoothly encapsulated and contains myxoid stroma. (d) Low-power photomicrograph (original magnification, x40; H-E stain) shows proliferation of fascicular interlacing spindle cells that resemble peripheral nerve tissue, along with loose fibrous stroma.
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Figure 11d. Schwannoma in a 70-year-old man. (a) Transverse contrast-enhanced CT scan shows a well-marginated low-attenuation mass interposed between the portal vein, superior mesenteric artery, aorta, and inferior vena cava. (b) On a T2-weighted MR image, the mass appears mostly hyperintense. (c) Photograph of the bisected gross specimen shows that the tumor is smoothly encapsulated and contains myxoid stroma. (d) Low-power photomicrograph (original magnification, x40; H-E stain) shows proliferation of fascicular interlacing spindle cells that resemble peripheral nerve tissue, along with loose fibrous stroma.
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Figure 12. Neurofibromas in a patient with neurofibromatosis type 1. Sagittal T2-weighted MR image shows multiple hyperintense masses in the presacral region (arrows).
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Figure 13a. Ganglioneuroma in a 21-year-old man. (a) Transverse contrast-enhanced CT scan of the abdomen shows a well-marginated, minimally enhancing mass in the right paraaortic region. (b) On a T2-weighted MR image, the mass appears hyperintense. (c) Photograph of the resected specimen shows an encapsulated, elastic hard mass with a myxoid component. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) demonstrates an arrayed proliferation of spindle cells with dispersed mature ganglion cells.
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Figure 13b. Ganglioneuroma in a 21-year-old man. (a) Transverse contrast-enhanced CT scan of the abdomen shows a well-marginated, minimally enhancing mass in the right paraaortic region. (b) On a T2-weighted MR image, the mass appears hyperintense. (c) Photograph of the resected specimen shows an encapsulated, elastic hard mass with a myxoid component. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) demonstrates an arrayed proliferation of spindle cells with dispersed mature ganglion cells.
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Figure 13c. Ganglioneuroma in a 21-year-old man. (a) Transverse contrast-enhanced CT scan of the abdomen shows a well-marginated, minimally enhancing mass in the right paraaortic region. (b) On a T2-weighted MR image, the mass appears hyperintense. (c) Photograph of the resected specimen shows an encapsulated, elastic hard mass with a myxoid component. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) demonstrates an arrayed proliferation of spindle cells with dispersed mature ganglion cells.
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Figure 13d. Ganglioneuroma in a 21-year-old man. (a) Transverse contrast-enhanced CT scan of the abdomen shows a well-marginated, minimally enhancing mass in the right paraaortic region. (b) On a T2-weighted MR image, the mass appears hyperintense. (c) Photograph of the resected specimen shows an encapsulated, elastic hard mass with a myxoid component. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) demonstrates an arrayed proliferation of spindle cells with dispersed mature ganglion cells.
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Figure 14a. Myxoid liposarcoma as a part of well-differentiated liposarcoma. (a) Transverse contrast-enhanced CT scan shows a huge mass with fat attenuation. A higher-attenuation area (arrow) is noted within the mass. (b) On a T2-weighted MR image, the high-attenuation area within the mass is markedly hyperintense (arrow). (c) Photograph of the resected specimen shows a well-circumscribed, yellowish fatty tumor. A whitish, elastic hard portion (arrow) is present within the tumor, a finding that is consistent with the high-attenuation and high-signal-intensity areas seen in a and b, respectively. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) of the elastic hard portion shows a pattern of myxoid liposarcoma, whereas the majority of the tumor demonstrated features of well-differentiated liposarcoma.
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Figure 14b. Myxoid liposarcoma as a part of well-differentiated liposarcoma. (a) Transverse contrast-enhanced CT scan shows a huge mass with fat attenuation. A higher-attenuation area (arrow) is noted within the mass. (b) On a T2-weighted MR image, the high-attenuation area within the mass is markedly hyperintense (arrow). (c) Photograph of the resected specimen shows a well-circumscribed, yellowish fatty tumor. A whitish, elastic hard portion (arrow) is present within the tumor, a finding that is consistent with the high-attenuation and high-signal-intensity areas seen in a and b, respectively. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) of the elastic hard portion shows a pattern of myxoid liposarcoma, whereas the majority of the tumor demonstrated features of well-differentiated liposarcoma.
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Figure 14c. Myxoid liposarcoma as a part of well-differentiated liposarcoma. (a) Transverse contrast-enhanced CT scan shows a huge mass with fat attenuation. A higher-attenuation area (arrow) is noted within the mass. (b) On a T2-weighted MR image, the high-attenuation area within the mass is markedly hyperintense (arrow). (c) Photograph of the resected specimen shows a well-circumscribed, yellowish fatty tumor. A whitish, elastic hard portion (arrow) is present within the tumor, a finding that is consistent with the high-attenuation and high-signal-intensity areas seen in a and b, respectively. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) of the elastic hard portion shows a pattern of myxoid liposarcoma, whereas the majority of the tumor demonstrated features of well-differentiated liposarcoma.
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Figure 14d. Myxoid liposarcoma as a part of well-differentiated liposarcoma. (a) Transverse contrast-enhanced CT scan shows a huge mass with fat attenuation. A higher-attenuation area (arrow) is noted within the mass. (b) On a T2-weighted MR image, the high-attenuation area within the mass is markedly hyperintense (arrow). (c) Photograph of the resected specimen shows a well-circumscribed, yellowish fatty tumor. A whitish, elastic hard portion (arrow) is present within the tumor, a finding that is consistent with the high-attenuation and high-signal-intensity areas seen in a and b, respectively. Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) of the elastic hard portion shows a pattern of myxoid liposarcoma, whereas the majority of the tumor demonstrated features of well-differentiated liposarcoma.
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Figure 15a. Leiomyosarcoma in a 48-year-old woman. (a) Transverse contrast-enhanced CT scan reveals a huge mass adjacent to the left kidney that displaces the spleen and pancreas anteriorly. The mass has heterogeneous enhancement with central nonenhancing foci that suggest necrosis. Enhanced vessels (arrow) are seen to penetrate the mass, a finding that reflects hypervascularity. (b) On a T2-weighted MR image, the mass is heterogeneous but relatively hypointense. The central portion has high signal intensity (arrow), a finding that represents necrosis. (c) Photograph of the resected specimen reveals that the mass is composed of yellow-white fibrous tissue with central necrosis. The mass was attached to the kidney but was separated from it at surgery. The adrenal gland was undetectable at first but was later identified at the tumor periphery, having a preserved fibrous capsule (false-positive phantom organ sign). Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) shows proliferating spindle-shaped cells with nuclear atypia and mitosis. An interlacing fascicular pattern compatible with leiomyosarcoma is also noted.
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Figure 15b. Leiomyosarcoma in a 48-year-old woman. (a) Transverse contrast-enhanced CT scan reveals a huge mass adjacent to the left kidney that displaces the spleen and pancreas anteriorly. The mass has heterogeneous enhancement with central nonenhancing foci that suggest necrosis. Enhanced vessels (arrow) are seen to penetrate the mass, a finding that reflects hypervascularity. (b) On a T2-weighted MR image, the mass is heterogeneous but relatively hypointense. The central portion has high signal intensity (arrow), a finding that represents necrosis. (c) Photograph of the resected specimen reveals that the mass is composed of yellow-white fibrous tissue with central necrosis. The mass was attached to the kidney but was separated from it at surgery. The adrenal gland was undetectable at first but was later identified at the tumor periphery, having a preserved fibrous capsule (false-positive phantom organ sign). Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) shows proliferating spindle-shaped cells with nuclear atypia and mitosis. An interlacing fascicular pattern compatible with leiomyosarcoma is also noted.
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Figure 15c. Leiomyosarcoma in a 48-year-old woman. (a) Transverse contrast-enhanced CT scan reveals a huge mass adjacent to the left kidney that displaces the spleen and pancreas anteriorly. The mass has heterogeneous enhancement with central nonenhancing foci that suggest necrosis. Enhanced vessels (arrow) are seen to penetrate the mass, a finding that reflects hypervascularity. (b) On a T2-weighted MR image, the mass is heterogeneous but relatively hypointense. The central portion has high signal intensity (arrow), a finding that represents necrosis. (c) Photograph of the resected specimen reveals that the mass is composed of yellow-white fibrous tissue with central necrosis. The mass was attached to the kidney but was separated from it at surgery. The adrenal gland was undetectable at first but was later identified at the tumor periphery, having a preserved fibrous capsule (false-positive phantom organ sign). Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) shows proliferating spindle-shaped cells with nuclear atypia and mitosis. An interlacing fascicular pattern compatible with leiomyosarcoma is also noted.
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Figure 15d. Leiomyosarcoma in a 48-year-old woman. (a) Transverse contrast-enhanced CT scan reveals a huge mass adjacent to the left kidney that displaces the spleen and pancreas anteriorly. The mass has heterogeneous enhancement with central nonenhancing foci that suggest necrosis. Enhanced vessels (arrow) are seen to penetrate the mass, a finding that reflects hypervascularity. (b) On a T2-weighted MR image, the mass is heterogeneous but relatively hypointense. The central portion has high signal intensity (arrow), a finding that represents necrosis. (c) Photograph of the resected specimen reveals that the mass is composed of yellow-white fibrous tissue with central necrosis. The mass was attached to the kidney but was separated from it at surgery. The adrenal gland was undetectable at first but was later identified at the tumor periphery, having a preserved fibrous capsule (false-positive phantom organ sign). Scale is in centimeters. (d) Photomicrograph (original magnification, x100; H-E stain) shows proliferating spindle-shaped cells with nuclear atypia and mitosis. An interlacing fascicular pattern compatible with leiomyosarcoma is also noted.
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Figure 16. Paraganglioma. Transverse unenhanced CT scan shows a large paraaortic mass with a fluid-fluid level. Surgical findings confirmed paraganglioma with hemorrhagic necrosis.
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Figure 17a. Retroperitoneal mucinous cystic tumor. (a) T2-weighted MR image shows a presacral multiloculated cystic mass without solid components. The tumor has high signal intensity. (b) Photograph of the specimen resected at laparotomy shows a large cystic tumor. The ovaries and the appendix were normal. (c) Photomicrograph (original magnification, x100; H-E stain) shows the cyst wall lined with columnar epithelial cells of the mucin-producing type. The underlying stroma resembles that of the ovary.
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Figure 17b. Retroperitoneal mucinous cystic tumor. (a) T2-weighted MR image shows a presacral multiloculated cystic mass without solid components. The tumor has high signal intensity. (b) Photograph of the specimen resected at laparotomy shows a large cystic tumor. The ovaries and the appendix were normal. (c) Photomicrograph (original magnification, x100; H-E stain) shows the cyst wall lined with columnar epithelial cells of the mucin-producing type. The underlying stroma resembles that of the ovary.
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Figure 17c. Retroperitoneal mucinous cystic tumor. (a) T2-weighted MR image shows a presacral multiloculated cystic mass without solid components. The tumor has high signal intensity. (b) Photograph of the specimen resected at laparotomy shows a large cystic tumor. The ovaries and the appendix were normal. (c) Photomicrograph (original magnification, x100; H-E stain) shows the cyst wall lined with columnar epithelial cells of the mucin-producing type. The underlying stroma resembles that of the ovary.
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Figure 18a. Lymphoma in a 64-year-old woman. (a) T2-weighted MR image shows a presacral mass with homogeneous low signal intensity that represents densely packed small round cells. (b) Photomicrograph (original magnification, x100; H-E stain) reveals proliferation of atypical lymphoid cells. The diagnosis was non-Hodgkin B-cell lymphoma.
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Figure 18b. Lymphoma in a 64-year-old woman. (a) T2-weighted MR image shows a presacral mass with homogeneous low signal intensity that represents densely packed small round cells. (b) Photomicrograph (original magnification, x100; H-E stain) reveals proliferation of atypical lymphoid cells. The diagnosis was non-Hodgkin B-cell lymphoma.
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Figure 19a. PNET in a 16-year-old boy. (a) Transverse contrast-enhanced CT scan shows a large, partially ill-defined mass with heterogeneous enhancement. The spleen and the left kidney are displaced anteriorly. (b) On a T2-weighted MR image, the mass appears heterogeneous with interpersed high-signal-intensity spots. At surgery, the tumor was seen to occupy the left side of the retroperitoneum and invade the thorax through the diaphragm. (c) High-power photomicrograph (original magnification, x200; H-E stain) shows proliferation of small round cells, a finding that is compatible with PNET or neuroblastoma. Because of the patient’s young age, the location of the tumor, and the lack of secretion of catecholamines, the final diagnosis was PNET.
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Figure 19b. PNET in a 16-year-old boy. (a) Transverse contrast-enhanced CT scan shows a large, partially ill-defined mass with heterogeneous enhancement. The spleen and the left kidney are displaced anteriorly. (b) On a T2-weighted MR image, the mass appears heterogeneous with interpersed high-signal-intensity spots. At surgery, the tumor was seen to occupy the left side of the retroperitoneum and invade the thorax through the diaphragm. (c) High-power photomicrograph (original magnification, x200; H-E stain) shows proliferation of small round cells, a finding that is compatible with PNET or neuroblastoma. Because of the patient’s young age, the location of the tumor, and the lack of secretion of catecholamines, the final diagnosis was PNET.
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Figure 19c. PNET in a 16-year-old boy. (a) Transverse contrast-enhanced CT scan shows a large, partially ill-defined mass with heterogeneous enhancement. The spleen and the left kidney are displaced anteriorly. (b) On a T2-weighted MR image, the mass appears heterogeneous with interpersed high-signal-intensity spots. At surgery, the tumor was seen to occupy the left side of the retroperitoneum and invade the thorax through the diaphragm. (c) High-power photomicrograph (original magnification, x200; H-E stain) shows proliferation of small round cells, a finding that is compatible with PNET or neuroblastoma. Because of the patient’s young age, the location of the tumor, and the lack of secretion of catecholamines, the final diagnosis was PNET.
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Figure 20a. Malignant paraganglioma in a 57-year-old man. (a) Abdominal CT scan shows an ill-defined, hypervascular tumor with a central low-attenuation focus, findings that were interpreted as a malignant tumor with central necrosis. (b) High-power photomicrograph (original magnification, x200; H-E stain) shows "zellballen" (cell ball) growth of chief cells with invasion into surrounding vessels and lymph nodes.
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Figure 20b. Malignant paraganglioma in a 57-year-old man. (a) Abdominal CT scan shows an ill-defined, hypervascular tumor with a central low-attenuation focus, findings that were interpreted as a malignant tumor with central necrosis. (b) High-power photomicrograph (original magnification, x200; H-E stain) shows "zellballen" (cell ball) growth of chief cells with invasion into surrounding vessels and lymph nodes.
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Copyright © 2003 by the Radiological Society of North America.
