A previously healthy 51-year-old woman presented to the emergency department with a 2-month history of dyspnea. The physical examination was notable for diminished breath sounds at both lung bases and a firm, nontender pelvic mass that appeared to originate from the left ovary. A chest radiograph showed pleural effusions that were greater on the right side than on the left (Panel A). Analysis of a pleural fluid sample revealed a sterile exudate with negative cytologic findings. Computed tomography of the abdomen (Panel B, coronal view) showed a pelvic mass (asterisk) and perihepatic ascites (arrows). The CA-125 level was 1794.0 IU per milliliter (reference value, <35.0). During a subsequent exploratory laparotomy, a left ovarian tumor was found. There were no peritoneal metastases. The solid, smooth tumor was excised (Panel C) and identified on histopathological analysis as a fibroma. Cytologic testing of the ascitic fluid was negative for a malignant condition. A diagnosis of Meigs’ syndrome — the triad of a benign ovarian tumor, ascites, and pleural effusion — was made. Meigs’ syndrome mimics ovarian cancer, but excision of the tumor results in the resolution of ascites and pleural effusion. Radiography was performed 3 weeks after surgery, at which time the patient’s symptoms, effusions, and ascites had abated.