Spontaneous bilothorax without previous surgery or trauma, a case report.

Bilothorax is a rare condition that can lead to severe infection and death. Most cases present with right-sided pleural effusion and the etiology can be biliary obstruction, infection, or iatrogenic complications. The diagnosis of bilothorax is confirmed by the ratio of pleural fluid to serum bilirubin >1. A 33-year-old Asian female presented with progressive dyspnea from right pleural effusion, which was confirmed to be biloma by pleural fluid to serum bilirubin ratio of 15.9. Imaging showed right-sided subdiaphragmatic nodule, which was subsequently biopsied on laparoscopy revealing hemorrhagic endometriotic lesion. However, there was no obvious diaphragmatic defect connecting pleural and peritoneal cavities. Additionally, no biliary leakage was identified by magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP). The treatment included antibiotics, tube thoracostomy, ERCP with stent, thermal ablation of endometriotic nodules under laparoscopy, and hormonal therapy for endometriosis. Bilothorax is rare case itself but the etiology secondary to endometriosis makes this case particularly unique.