Stable Pleural Effusion as a Diagnostic Pitfall in Meigs Syndrome: A Case of a Benign Brenner Tumor with Elevated CA125

We report a rare case of Meigs' syndrome caused by a benign Brenner tumor in a 74-year-old woman. The diagnosis was delayed because of a one-year history of unexplained, persistently stable exudative pleural effusion. The subsequent worsening of effusion and new-onset ascites prompted imaging, which revealed a large pelvic mass and elevated cancer antigen 125 levels. Tumor resection resulted in the complete resolution of the fluid collection. This case illustrates that Meigs' syndrome can present with indolent exudative effusion. Therefore, a thorough pelvic evaluation should be considered in postmenopausal women with unexplained pleural effusion to prevent any diagnostic delays.