A Struma Ovarii Associated with Pseudo-Meigs' Syndrome is Misdiagnosed as Advanced Ovarian Cancer: A Case Report

Introduction: A struma ovarii is a benign monodermal teratoma, composed of mature thyroid tissue. The presentation of this disease with pseudo-Meigs' syndrome [characterized by ascites, pleural effusions, and elevated cancer antigen-125 (CA-125) levels] may result in an advanced ovarian cancer misdiagnosis. Case Presentation: The patient was a 54-year-old woman with dyspnea, abdominal distention, and pseudo-Meigs' syndrome. She had a final diagnosis of struma ovarii, misdiagnosed as advanced ovarian cancer. She is currently asymptomatic (after surgery) and has a normal CA-125 level. Conclusions: The preoperative diagnosis of struma ovarii is difficult, and if it presents with pseudo-Meigs' syndrome, it may be initially misdiagnosed as advanced ovarian cancer. Using the frozen-section procedure, unnecessary extensive surgeries can be prevented.