A47-17 Thoracic Endometriosis Diagnosed via Pleural Fluid Cytology and Managed by Robotic-Assisted Pleurectomy: A Case Report

Background Thoracic endometriosis syndrome (TES) is a rare extra-pelvic manifestation of endometriosis involving the pleura or lungs, most commonly presenting as catamenial pneumothorax or hemothorax. Diagnosis is often delayed due to nonspecific symptoms and low cytologic yield. Case Summary A 26-year-old woman presented with recurrent right-sided pleuritic pain and dyspnoea associated with menstruation. Imaging showed a large right pleural effusion. Pleural fluid cytology revealed glandular and stromal cells consistent with endometrial tissue, confirmed by immunohistochemistry positive for ER and BerEP4. She underwent robotic-assisted thoracoscopic pleurectomy with resection of endometrial implants and repair of diaphragmatic fenestrations. Postoperative hormonal suppression with a GnRH analogue resulted in complete symptom resolution and no re-accumulation of fluid on subsequent follow up. Conclusion Although rarely diagnostic, pleural fluid cytology with immunohistochemistry can confirm TES non-invasively and facilitate timely surgical management. Robotic pleurectomy with diaphragm repair offers a safe, definitive option when combined with hormonal suppression. This abstract is funded by: Self