A Rare Case of Struma Ovarii Presenting as an Abdominal Mass in a 15-year-old Girl.

Struma ovarii is an uncommon monodermal ovarian teratoma. Symptoms are often nonspecific, which may lead to misdiagnosis. We report a rare case of a 15-year-old girl who presented with a painless left abdominal mass. Imaging revealed a sizable ovarian lesion, which was then resected via a lower midline laparotomy. This case highlights the diagnostic challenge of distinguishing struma ovarii from other ovarian neoplasms in adolescents. We also describe our surgical approach and management considerations.