Immunohistochemical studies of cell differentiation in a juxtaglomerular tumor

A renal tumor removed from a 29-year-old woman, who recently had had onset of primary hypertension, showed the histologic and ultrastructural features of a renin-secretory juxtaglomerular cell tumor. The expression of Factor VIII-related antigen (FVIII-RAG) was evaluated to identify endothelial differentiation of tumor cells in this lesion. Control tissue and vessels within the tumor showed normal expression of FVIII-RAG, but tumor cells as well as normal juxtaglomerular cells showed no localization of this antigen, which suggests the nonendothelial nature of these specialized cells.