FINE-NEEDLE ASPIRATION CYTOLOGY OF RENAL ANGIOMYOLIPOMA - REPORT OF ACASE WITH IMMUNOCYTOCHEMICAL AND ELECTRON-MICROSCOPIC FINDINGS

A case is presented in which the diagnosis of renal angiomyolipoma was made by computed tomography (CT)-guided, fine-needle aspiration cytol ogy and the examination of a cell block. The tumor was characterized b y epithelioid smooth muscle cells, blood vessels and fat in the cytolo gic material. The cytodiagnosis was further substantiated by positive staining of the epithelioid muscle cells for markers of muscle-specifi c actin, HMB45, and trace positivity for vimentin but not with S100 pr otein, desmin, or cytokeratin. Further studies for the recently descri bed crystalloids were also performed by using the periodic-acid Schiff stain with and without diastase treatment and electron microscopy on the cytologic material. However, no such crystalloids were found. A pr eoperative cytologic diagnosis of renal angiomyolipoma was considered to be of value due to the difference in management between angiomyolip oma and a renal carcinoma, both of which can present as a renal mass o n imaging. (C) 1998 Wiley-Liss, Inc.