Juvenile Granulosa Cell Tumor of the Testis: A Comparative Immunohistochemical Study with Normal Infantile Gonads

This study concerns the nature of two different cell populations in a juvenile granulosa cell tumor (GCT) of the infantile testis. Immunohistochemical features of the tumor were compared with those of normal infantile testes (six cases) and ovaries (six cases). The testicular neoplasm showed follicles, cysts and solid nodules composed of an internal layer of polyhedral cells that expressed cytokeratin and vimentin. Most of the follicles and nodules were surrounded by an external layer of spindle cells that reacted to muscle-specific actin, vimentin, and focally to desmin. A neoplastic rather than reactive origin of the spindle cell population is favored by their concentric arrangement in a peritubular-like or theca-like fashion and by their immunohistochemical correlation with normal peritubular-myoid and theca externa cells. Sertoli and granulosa cells of normal infantile gonads were positive for cytokeratin and vimentin; peritubular myoid and theca externa cells expressed muscle-specific actin, vimentin...