Clinicopathologic study of primary renal hemangioblastoma

To study the clinicopathologic characteristics of primary renal hemangioblastoma.The morphologic features, immunophenotype and molecular findings of 3 cases of primary renal hemangioblastoma were studied, with review of literature.The age of patients ranged from 43 to 57 years. There were 2 women and a man. The patients often presented with renal mass. Histologically, the tumors were surrounded by thick fibrous capsule and composed of epithelioid or spindle cells. Two cases had a prominent stromal component and the other one was rich in capillary network. Lipid vacuoles were observed in all cases. Features of hemorrhage were demonstrated in 2 cases. Capsular invasion and necrosis were seen in 1 case. Immunohistochemical study showed that the stromal cells were positive for alpha-inhibin (3/3), S-100 protein (3/3), EGFR (2/2), PAX-2 (2/2), PAX-8 (2/2) and CA9 (2/2) but negative for CKpan (2/2) and HMB45 (2/2). Focal membranous staining for CD10 (3/3) was noted. No VHL gene mutations or chromosome 3p deletion were detected in the 2 cases studied.Renal hemangioblastoma shows distinctive morphologic appearance with a wide range of variation. The unexpected positive staining for PAX-2, PAX-8 and CD10 in renal hemangioblastoma needs to be aware. Immunohistochemical study may be helpful in differential diagnosis of these renal tumors.