Abstract
BACKGROUND: Meigs syndrome is characterized by the association of a benign ovarian tumor, typically an ovarian fibroma, with pleural effusion and ascites. CASE SUMMARY: This report presents a case of a 54-year-old woman who was misdiagnosed with malignant ovarian neoplasm due to the presence of significant abdominal distension and elevated CA125 levels. Initial imaging at multiple external facilities suggested a left-sided malignant ovarian tumor, leading to unnecessary delays in treatment. Upon admission to our institution in April 2024, imaging confirmed a large pelvic mass, and subsequent diagnostic procedures indicated a likely fibroma. Surgical intervention revealed a left ovarian thecoma, and post-operative pathology confirmed the diagnosis. Notably, CA125 levels decreased from 335.1 U/ml to 164.6U/ml following surgery, and the patient showed significant clinical improvement. CONCLUSION: This case underscores the importance of considering Meigs syndrome in patients presenting with ovarian masses, pleural effusions, and elevated CA125, to prevent misdiagnosis and ensure timely management.