Adult Granulosa Cell Tumor : Immunostains
Immunohistochemistry of Adult Granulosa Cell Tumors of the Testis: The tumor cells are immunoreactive for inhibin (shown here), vimentin, calretinin, and CD99. They may be positive for melan A, FOXL2, SMA, and S-100 protein. There may be paranuclear dot-like positivity for low molecular weight cytokeratins (CK8, CK18). Nuclear beta-catenin and EMA are negative. FOXL2 and SF1 are highly sensitive but not specific as they tend to be positive in other sex cord-stromal tumors as well. FOXL2 mutation is seen in adult granulosa cell tumors (considerably more common in ovarian than in testicular).