C43-21 The Effusion Illusion: A Case of Mistaken Identity

Abstract Introduction Pseudo-Meigs syndrome is often an overlooked entity in patients presenting with recurrent pleural effusions. It can pose a diagnostic challenge for physicians and prompt recognition is critical, as misdiagnosis can significantly affect quality of life and patient outcomes. Here, we present a case of recurrent large pleural effusion, ascites and large ovarian mass, identified later as mucinous adenocarcinoma. All these findings together suggest a diagnosis of Pseudo-Meigs syndrome. Case Presentation A 69-year-old female with a past medical history of symptomatic bradycardia status post pacemaker that presented to the hospital with 2 weeks of shortness of breath and dry cough. Past surgical history included complete hysterectomy 10 years prior to presentation. Vital signs were stable and physical exam was unremarkable, but initial work-up showed leukocytosis. Chest CT showed large right pleural effusion and small volume ascites. She had a thoracentesis with 2.4L of fluid removed. Studies showed exudative effusion, and cytology was negative for malignancy. Her dyspnea improved following the procedure, and she was treated for suspected parapneumonic effusion with 5 days of antibiotics. At a two-week follow-up appointment, she presented with dyspnea. CXR showed recurrent right-sided pleural effusion. She underwent thoracentesis with 2.5L removed. Studies revealed exudative effusion with negative cytology. Three weeks later, she developed sudden onset dyspnea and presented to the hospital. She was hypoxic and placed on 3L nasal cannula. Chest CT showed larger right pleural effusion with mediastinal shift. Chest tube was placed and yielded 2.6L of serosanguinous fluid immediately. Studies were again exudative, and cytology was negative for malignancy. Ultimately a CT abdomen/pelvis was done which showed a very large pelvic mass that measured 10.8 x 16.8 cm in size with evidence of abdominal, pelvic ascites and bilateral hydronephrosis. CA 125 and CA 19-9 were elevated at more than 4,000. Gynecology Oncology was consulted, and she underwent exploratory laparotomy with bilateral salpingo-oophorectomy, appendectomy, omentectomy, short bowel repair and lysis of adhesions. During surgery, the large irregular mass was ruptured causing bloody ascites as she developed hemorrhagic shock. Pathology was positive for ovarian mucinous adenocarcinoma of the left ovary. Discussion This case presents the diagnostic challenges physicians face when managing pleural effusions. Prompt recognition is critical, as misdiagnosis can significantly affect quality of life and patient outcomes. Clinicians should consider that in rare cases recurrent pleural effusions can be due to Pseudo-Meigs syndrome. This abstract is funded by: None