Pediatric sex cord-stromal tumor with composite morphology: a case report.

A 12-year-old female with developmental delay/mental retardation and a family history of gynecologic cancers presented with nonspecific abdominal complaints and was found to have a 4.5-kg, 25- x 23- x 15-cm pelvic mass with solid and cystic components and associated retroperitoneal and mesenteric lymphadenopathy. Laboratory studies revealed increased serum levels of CA-125 and inhibin B. Histologically, the tumor exhibited several different morphologic appearances including adult granulosa cell tumor, juvenile granulosa cell tumor (with areas of marked atypia), and Sertoli cell tumor. Immunohistochemically, the tumor was positive for calretinin, MIC-2 (CD99), S100 protein, PGP 9.5, and neuron-specific enolase. Electron microscopy of the Sertoli cell tumor-like areas showed Charcot-Bottcher filaments, a distinguishing feature of Sertoli cells. Together, these findings supported a diagnosis of mixed sex cord-stromal tumor including granulosa cell tumor of adult and juvenile types and intermediate- to high-grade Sertoli cell tumor, with large areas of markedly atypical sex cord-stromal tumor.