A Diagnostic Trifecta Case Report: Struma Ovarii with Pseudo-Meigs Syndrome and Subsequent Ovarian Remnant Syndrome

Abstract

Struma ovarii is a rare ovarian teratoma composed predominantly of thyroid tissue, representing less than 1% of all ovarian tumors. The clinical presentation of struma ovarii can vary widely, from an asymptomatic palpable abdominal mass, hyperthyroidism (elevated free T4 and/or T3; low TSH), and, in rare cases, pseudo-Meigs syndrome. Diagnosis is often based on postoperative histopathological confirmation of thyroid tissue. We present a case of a 44-year-old Hispanic female with an incidental finding of an adnexal mass, pleural effusion, and ascitic fluid, but with normal tumor markers, cancer antigen 125 (CA-125), and carcinoembryonic antigen (CEA). Postoperative pathological examination confirmed struma ovarii, with pseudo-Meigs syndrome. Unexpectedly, the patient developed ovarian remnant syndrome (ORS). This case contributes to the limited literature describing struma ovarii associated with pseudo-Meigs syndrome and normal tumor markers, highlighting the diverse clinical spectrum of this tumor. It also underscores the need for a high index of suspicion for struma ovarii in atypical cases, regardless of tumor marker levels. The development of ORS further emphasizes the importance of long-term follow-up after definitive surgical management.