Leydig cell tumor of the testis: a case diagnosed by fine-needle sampling without aspiration with histologic, immunohistologic, and electron microscopic analysis.

Fine-needle sampling without aspiration was performed in a patient with a testicular mass. The cytologic diagnosis was consistent with Leydig cell tumor. Cytologic features included abundant grey-blue cytoplasms with spherical or oval nuclei in May-Grünwald-Giemsa-stained smears. Intranuclear inclusions were observed but no Reinke's crystals were detected. Histologic findings confirmed the diagnosis and tumor cells were positive for vimentin. Electron microscopic analysis of the tumor showed abundant smooth endoplasmic reticulum and mitochondria with tubulovesicular cristae but no Reinke's crystals.