CASE PRESENTATION: A 70 year old smoker male with PMH of DM, HTN, CABG, presented with 2 month history of SOB and no other complaints. His vitals were stable and exam was only remarkable for decrease breath sounds at right base. CXR showed right sided pleural effusion (fig A). Thoracentesis yielded 800 ml of amber colored fluid. Repeat CXR showed incomplete lung expansion (fig B). Fluid analysis revealed pH 7.3, RBC 646000, WBC 4922 ( 48% lymphocytes, 24% neutrophils, 3% eosinophils, 25% macrophages), LDH 2695, protein 3.0 and glucose <5. Infectious, oncological and rheumatological workup was negative. He was discharged home. Symptoms recurred 3 months later. CT chest showed recurrence of right sided pleural effusion (fig C). 1200 ml of exudative fluid was drained by interventional radiology. Repeat workup was again negative. An out patient PET scan was normal and he refused pleural biopsy. Pleural effusion recurred again in 8 weeks and he was sent for surgery. A 18 x 12 cm fluid filled cyst with adhesive attachments to pericardium and diaphragm was removed. Histopathological analysis showed chorionic villi like structures confirming diagnosis of Placental Transmogrification of the lung (fig D). He remained asymptomatic 6 months post surgery.