Neoplasms that have features of Leydig cells, Sertoli cells, granulosa cells, or rarely, theca cells. (No normal granulosa or theca cells in testis)
Very rarely is mixed with GCTs (Gonadoblastoma).
4-6% of adult testicular neoplasm, with higher proportion (30%) of testicular tumors in infants and children.
No racial difference in frequency (unlike GCT which is more common in Caucasians).
Histogenesis is poorly understood and may relate to disruption of hypothalamic-pituitary-testicular axis and hormonal disturbance.
Associated with genetic syndromes such as Peutz-Jeghers syndrome (Large cell calcifying Sertoli cell tumor), Carney syndrome and testicular feminization syndrome (Sertoli cell tumor).
Unlike germ cell tumor, has no definitive association with cryptorchidism.
Presents mostly as painless mass or with hormone-related symptoms (isosexual pseudoprecocity, gynecomastia or impotence).
Immunohistochemistry: All SCST are inhibin+, calretinin+. (useful vs. GCT)
Approximately 10% of adult-type SCSTs are malignant and may metastasize.
Metastasis is the ONLY reliable criterion for malignancy.
Histologic features associated with malignancy: nuclear pleomorphism, frequent and abnormal mitosis (>4/10 HPF), necrosis, infiltrative growth, large size (>5 cm), paratesticular extension, and vascular invasion.
Tumors in infants and children often have benign behavior.