72 y/o Caucasian male with a past medical history of hypertension, non-ischemic cardiomyopathy, dyslipidemia and CVA presents with worsening shortness of breath over past one month. Our patient also has a long standing history of tobacco abuse and an employment history of working ship broiler rooms. Chest examination revealed no breath sounds on left side. Chest radiography revealed complete opacification of the left hemithorax with a mediastinal shift from left to right (Figure 1). A computed tomographic scan of the chest showed a large left hydropneumothorax with complete collapse of the left lung. Also noted was a mediastinal shift towards the right associated with a small right pleural effusion with right lower lobe atelectasis and small pericardial effusion (Figure 2). The management of this collapsed lung is surgical, with removal of the fibrosed visceral pleura to allow for the expansion of the underlying lung. In this patient, video-assisted thoracoscopic surgery and decortication was performed. Bronchial washings showed benign bronchial epithelial cells mixed with alveolar macrophages. Pleural biopsy revealed a poorly differentiated neoplasm carcinoma versus mesothelioma. Fragments of fibrous soft tissue and clusters of pleomorphic neoplastic cells were negative for adenocarcinoma markers (CEA-m, EpCam, and BerEP4). They instead expressed mesothelial markers including Calretinin and GLUT-1, favoring a diagnosis of mesothelioma.