Contributed by Sarah E. Martin1, Sohaib M. Al-Khatib1, Michael S. Turner2, Annette C. Douglas-Akinwande3, and Eyas M. Hattab1
1Department of Pathology and Laboratory Medicine and 3Department of Radiology, Indiana University School of Medicine, Indianapolis, Indiana and 2Indianapolis Neurosurgery Group, Methodist Hospital, Indianapolis, Indiana, USA
In 1995, at the age of 29, a woman presented with headache and visual disturbances. She was found to have a capillary hemangioblastoma of the brainstem, which was then resected and pathologically confirmed. The diagnosis of von Hippel-Lindau disease was suspected at this time. One year later, she presented with worsening headache, nausea, vertigo, photophobia, and episodes of unresponsiveness. CT and MRI revealed a 4 cm mass in the right cerebellar hemisphere with effacement and displacement of the fourth ventricle. A VP shunt was placed semi-emergently, and two days later she underwent a second craniotomy for tumor resection. The diagnosis of hemangioblastoma was once again confirmed. In 2004, follow-up MRI of the brain and spine revealed multiple brainstem and cervical and thoracic cord lesions consistent with hemangioblastomas. An abdominal scan showed cystic kidneys with bilateral enhancing heterogeneous renal masses, suspicious for malignancy, as well as multiple pancreatic cysts and a paraaortic nodule of possible left adrenal origin; however a bone scan was normal. It is unclear whether or not the patient was treated for the presumed renal cell carcinoma at this time. In 2007, the then 41-year-old patient presented with a three-day history of falls and disequilibrium, progressive quadriparesis and difficulty swallowing. An MRI of the brain was performed. Axial T2 (Figure 1) and contrast enhanced T1-weighted (Figure 2) images showed a partially cystic (thick arrow) enhancing cerebellar mass, dorsal to the fourth ventricle. Extensive T2 hyperintensity was present in the pons, medulla (thin arrows) and middle cerebellar peduncles. Sagittal unenhanced (Figure 3) and contrast enhanced (Figure 4) T1-weighted images showed a markedly enhancing (black arrowhead) solid mass inferior to the fourth ventricle. Nodular leptomeningeal enhancement on the anterior surface of the pons was consistent with a leptomeningeal tumor. The patient underwent a posterior fossa craniotomy with gross total resection of the mass in April 2007.
Grossly, multiple fragments of an irregular gray-tan to red-brown rubbery tissue with a red-brown hemorrhagic cut surface were submitted for pathologic examination.
Microscopic examination revealed a well-circumscribed, moderately cellular, highly vascular, and hemorrhagic tumor made up of polygonal vacuolated cells characterized by round hyperchromatic nuclei with mild pleomorphism (Figures 5, 6). The tumor showed areas of cystic degeneration and was focally rimmed by gliotic brain tissue with Rosenthal fibers (Figure 7). Embedded within the tumor was an ill-defined 3mm nodule that blended in with the surrounding tissue but appeared slightly less vascular (Figures 8, 9). The epithelioid polygonal tumor cells comprising the nodule were characterized by a finely granular eosinophilic cytoplasm and larger round to oval nuclei with prominent nucleoli (Figure 10). The tumor cells within the nodule were immunoreactive for cytokeratin AE1/AE3 (Figure 11), CD10 (Figure 12), and EMA (Figure 13) and negative for inhibin-alpha (Figure 14), while the tumor cells outside the nodule stained positive for inhibin-alpha, but negative for cytokeratin AE1/AE3, CD10, and EMA (Figs 11, 12, 13 and 14). Both tumor cell types were negative for CAM 5.2. FINAL DIAGNOSIS