Black Pleural Effusion a Case of Thoracic Endometriosis

Abstract Introduction: Thoracic endometriosis is a rare disease process seen in women of reproductive age characterized by the presence of endometrial tissue in the thoracic cavity. It usually presents with pneumothorax but less likely present with pleural effusion. Black pleural effusion is in itself an extremely rare presentation. There are no reported cases of thoracic endometriosis with black pleural effusion. Description: This describes the diagnostic and management dilemma of a case of a 42-year-old female who presented with progressive dyspnea and increasing abdominal girth for 10 months. Physical examinations and imaging were consistent with pleural effusion and ascites. Subsequent diagnostic and therapeutic paracentesis and thoracentesis yielded an unusually black ascitic fluid and pleural effusion respectively. Subsequent imaging and diagnostic tests lead to elimination of possible differentials but nonetheless were not diagnostic.Video-assisted thoracoscopic surgery (VATS) was performed for definitive diagnosis and management. Intraoperative findings included multiple pleural implants appearing as brown colored nodules. Histopathological examination of the biopsied tissue confirmed the presence of endometrial glands consistent with thoracic endometriosis.Postoperatively, the patient was started on gonadotropin-releasing hormone (GnRH) agonist therapy to suppress ovarian function and reduce the recurrence of endometrial tissue. The patient reported significant improvement in symptoms, and follow-up imaging showed resolution of the pleural effusion and no new lesions. She continues to be monitored regularly with clinical evaluations and imaging studies.Novelty and Clinical Relevance: The case highlights the importance of considering thoracic endometriosis in the differential diagnosis of black pleural effusion in women, particularly those with a history of endometriosis. Early recognition and appropriate management, including surgical intervention and hormonal therapy, can lead to favorable outcomes.