A 40yr old female came with chief complaints of shortness of breath and left sided chest pain since 25days.She had similar complaints 6monthsback, where thoracentesis was done with ICD and relieved .History of increase in dyspnoea since 20days and again planned for ICD where there was a DRYTAP .On examination and necessary investigations , it was found to be LEFT LOCULATED PLEURAL EFFUSION/EMPYEMA .Left posterolateral thoracotomy and decortication was planned under general anaesthesia. Pus was sent to culture & sensitivity .Intra pleural contents along with visceral and parietal pleura were sent to HPE, where it was diagnosed as MUCINOUS ADENOCARCINOMA WITH TUBULOPAPILLARY PATTERN .Post operatively patient was stable and referred to oncology department for further management