Coexistence of ovarian serous cystadenoma, mature cystic teratoma and primary amenorrhea with a polycystic ovary syndrome-like phenotype in an adolescent with Proteus syndrome: a case report

Proteus syndrome (PS) is a rare, sporadic overgrowth disorder that involves multiple organ systems, leading to physical disfigurement and increased tumor susceptibility. Gynecologic neoplasms have occasionally been reported, but the concurrence of multiple gynecologic tumors, non-iatrogenic primary amenorrhea and a polycystic ovary syndrome-like (PCOS-like) phenotype in a single patient has not previously been described. We report such a case in an adolescent with genetically confirmed PS. A 15-year-old girl with genetically confirmed PS underwent laparoscopic exploration for a complex pelvic mass. Histopathology demonstrated an ovarian serous cystadenoma arising from the left ovary, with benign non-invasive serosal implants on the anterior uterine wall and mesocolon, a separate mature cystic teratoma in the right ovary, and bilateral multiple cystic follicles with stromal nodular hyperplasia. Postoperative evaluation for primary amenorrhea showed persistent ovarian-pattern hyperandrogenism with no evidence of ovulation, consistent with a PCOS-like phenotype. Combined hormonal therapy produced regular withdrawal bleeding but was discontinued after a calf-vein thrombotic event. No cystadenoma recurrence was observed during multidisciplinary follow-up. This case expands the recognized spectrum of gynecologic and reproductive-endocrine manifestations in PS and illustrates a previously unreported non-iatrogenic primary amenorrhea with preserved internal genitalia and a PCOS-like phenotype. Individualized gynecologic surveillance may be considered on a case-by-case basis, although the optimal screening strategy remains undefined owing to the limited number of reported cases.