Ten cases of a distinctive testicular neoplasm characterized by large cells with abundant eosinophilic cytoplasm and calcification are reported together with two similar cases from the literature. A Sertoli cell origin of these tumors was established by their architectural and cytologic characteristics, as well as their frequent growth within seminiferous tubules. A high association was found with unusual features, including bilaterality (six cases), multifocality (six cases), complex endocrine disorders, (three cases), and familial occurrence and cardiac myxoma (two cases). Eleven of the 12 cases had benign courses, but one was associated with metastases that caused death.