[37] Peripheral Hemangioblastoma: Clinicopathologic & Immunohistochemical Analysis of 21 Cases

Leona A Doyle, Christopher DM Fletcher. Brigham and Women's Hospital, Harvard Medical School, Boston, MA

Background: Hemangioblastoma is a rare tumor of uncertain histotype that typically arises in the cerebellum, often in the setting of Von Hippel-Lindau syndrome (VHL). Exceptional cases of hemangioblastoma arising outside the central nervous system (CNS) have been reported, but little is known about their clinicopathologic and immunohistochemical features.
Design: 21 cases of hemangioblastoma arising at peripheral sites (PH) were identified in consult files. Clinical, morphologic and immunohistochemical features were evaluated. Outcome data were obtained from referring pathologists.
Results: 11 patients were female and 10 male; median age was 58 years (range 27-79). Tumors arose in spinal nerve roots (12), kidney (3), intestine (2), orbit (1), forearm (1), peritoneum (1) and flank (1). 5 patients had VHL; another 5 had lesions suggestive of VHL. 1 patient had tuberous sclerosis. Median tumor size was 4 cm (range 1.3-15 cm). Most tumors were well circumscribed; 6 were infiltrative-3 extended into bone and 1 into pleura. Tumors had a complex capillary network with larger thin or thick walled vessels in a solid and often lobular growth pattern, similar to CNS hemangioblastoma. In 9 cases the larger vessels showed a branching hemangiopericytoma-like pattern. All tumors had an admixed population of plump spindle cells and microvacuolated cells with pale eosinophilic or clear cytoplasm, which often mimicked lipoblasts or renal cell carcinoma (RCC). In 5 cases the microvacuolated cells were scant. Stromal cell nuclei were hyperchromatic or vesicular with inconspicuous nucleoli. 4 tumors showed marked nuclear pleomorphism. Mitotic activity was low (range <1-2/10 HPF). No necrosis or lymphovascular invasion was identified. Tumor cells expressed inhibin in 95% (19/20), NSE in 79% (15/19), S100 in 63% (12/19), as well as GLUT1 (7/10, mostly weak), SMA (4/5), EMA (2/8, focal), PAX-8 (1/10), aquaporin (3/6) and desmin (1/4). Brachyury was consistently negative (0/19), as were keratin, HMB-45, melanA and GFAP. CD31 and CD34 highlighted tumor vasculature. Follow up information was available for 17 patients (mean 34 months; range 5-117). 1 patient died of metastatic RCC. 3 had locally persistent PH after incomplete resection. Local recurrence or distant metastasis has not been identified in any patient so far.
Conclusions: PH is rare but may mimic some malignant tumors; the distinct immunohistochemical profile can aid diagnosis. Unresectable cases may be locally aggressive, but complete excision appears to be curative. Recognition of this tumor may identify patients in whom testing for VHL is warranted.
Category: Bone & Soft Tissue

Monday, March 4, 2013 1:00 PM

Poster Session II # 6, Monday Afternoon


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