320 Thoracic Endometriosis Causing Recurrent Effusions and Multiple Pleural Nodules

Abstract Introduction/Objective Endometriosis is a benign condition characterized by the presence of benign endometrial tissue implanted in locations outside of the uterine cavity. While the disease predominantly affects the abdominopelvic organs, thoracic endometriosis represents the most common site of extrapelvic involvement, with a known predilection for the right hemithorax. Methods/Case Report A 30-year-old female with a known history of endometriosis and recurrent pleural effusions presented with progressive dyspnea. Chest radiography and a CT scan of the thorax revealed a large, concentrically loculated right pleural effusion extending from the lung apex to the base. The patient subsequently underwent open thoracotomy with pleurodesis, which revealed dense adhesions involving the lung, chest wall, diaphragm, and mediastinum, along with multiple nodular lesions. Histopathological examination showed marked pleural thickening accompanied by hemorrhage, congestion, chronic inflammation, and numerous reactive nodular lesions. Few endometrial glands with associated stroma were identified, stained positive for Pax8, ER, and CD10, findings consistent with thoracic endometriosis. Results NA Conclusion Recurrent pleural effusion accompanied by multiple pleural nodular lesions raises suspicion for malignancy. Although rare, increased awareness of thoracic endometriosis among clinicians and pathologists is crucial to facilitate timely diagnosis and appropriate multidisciplinary management.