Useful immunohistochemical markers in differentiating hemangioblastoma versus metastatic renal cell carcinoma

Hemangioblastomas (HBs) account for nearly a tenth of all posterior fossa neoplasms and can be the presenting finding in patients with von Hippel-Lindau (VHL) syndrome. HB must be differentiated from renal cell carcinoma (RCC), also seen in VHL, as the distinction between these lesions dictates the management of these patients. Currently inhibin A and RCC marker have been used in the diagnosis of HB and metastatic RCC, both with inconsistent results. Additional immunohistochemical markers including CD10, PAX-2, D2-40, and FLi-1 have been shown to have potential for the distinction of these two entities. Fifteen cerebellar HBs and 17 metastatic clear cell RCCs to the brain were selected for the study. All cases were immunostained with RCC marker, inhibin, CD10, PAX-2, D2-40, and Fli-1. The staining patterns were scored based on intensity and extent of tumor staining. In the differentiation of HB and metastatic RCC, D2-40 and RCC marker proved to be poor markers with less than 50% of HBs and RCCs, respectively, showing positive staining. PAX-2 and CD10 were superior to RCC marker in the diagnosis of metastatic RCC, with PAX-2 having better specificity. Fli-1 failed to stain tumor cells in both HBs and RCC. Inhibin A, in combination with PAX-2, showed to be the most useful markers to differentiate HB from metastatic RCC.