Myoid gonadal stromal tumor: A rare testicular sex cord stromal neoplasm – a case report and review of the literature

Myoid gonadal stromal tumor (MGST) is an exceptionally rare benign testicular sex cord–stromal neoplasm with limited published experience. We report a 30-year-old man presenting with a painless right testicular mass and normal serum tumor markers. Ultrasonography and magnetic resonance imaging demonstrated a small enhancing intratesticular lesion suspicious for malignancy. Radical inguinal orchiectomy was performed. Histopathological and immunohistochemical evaluation was consistent with MGST, showing spindle-cell proliferation with diffuse smooth muscle actin, S100, and vimentin positivity and focal inhibin expression. No recurrence or metastasis occurred during 12 months of follow-up. This case highlights the diagnostic challenge and rarity of MGST.