Microscopic Sertoliform Sex Cord Proliferation Involving Pelvic Peritoneum: Report of a Case Associated With Endosalpingiosis.

Microscopic sex cord proliferations are an uncommon finding, most often associated with ovarian or uterine stromal, epithelial, or mixed epithelial and stromal neoplasms. Rarely they occur in conjunction with a non-neoplastic process such as endometriosis or adenomyosis, and occasionally in the absence of concurrent pathology in locations such as the fallopian tube. Most reports of this phenomenon document adult granulosa cell tumor-like morphology but more uncommonly the proliferations exhibit Sertoliform features. We report a case of a multifocal sex cord proliferation (inhibin and calretinin positive; BerEP4 and epithelial membrane antigen negative) with Sertoliform features occurring in the pelvic peritoneum and associated with endosalpingiosis, a previously unreported phenomenon. We discuss the differential diagnosis and speculate that this represents a non-neoplastic phenomenon.