Abstract Spermatocytic seminoma is a rare germ cell tumor distinct from classical seminoma, both clinically and pathologically. It affects older men, has not been associated with a history of cryptorchidism, and has no known counterpart in ovary or any other site. Pathologically, it is characterized by 3 distinct cell types, lack of cytoplasmic glycogen, and scant to absent lymphocytic infiltrate. Gain of chromosome 9 is the most consistent genetic abnormality. There have been few case reports of sarcomas arising in spermatocytic seminoma and only an occasional report of metastasis. It is important to differentiate this condition from its frequent mimics, such as classic seminoma and embryonal carcinoma, because patients with spermatocytic seminoma may not require further treatment after surgery.