Laboratory examination showed a normal CBC count and transaminase levels, but mild elevations of amylase level (168 IU/L), lipase level (169 IU/L), glucose level (235 mg/dL), erythrocyte sedimentation rate (30 mm/h), and C-reactive protein level (2.9 mg/dL). The chest radiograph showed a massive left pleural effusion (Fig 1). Enhanced thoracoabdominal CT scan revealed a massive left pleural effusion as well as a protruding, encapsulated, fluid-filled cystic lesion (Figs 2A, 2B, asterisk) derived from the pancreatic tail. The lesion was 24 mm × 47 mm in size, and it expanded upward, contacting the posterior gastric wall of the fornix (Fig 2B, white arrow) along with the left crura of the diaphragm (Fig 2C, black arrows), connecting to the left thoracic cavity (Fig 2C, double asterisk). Peripancreatic fat with a high-density area was also noted (Fig 2A, white arrowheads). Thoracentesis fluid on the left side was black in color (Fig 2D), and fluid analysis showed lactate dehydrogenase level 784 IU/L, total protein level 4.4 g/dL, glucose level 115 mg/dL, and hematocrit level 0.1%, consistent with an exudative pleural effusion. Cytology of the centrifugation sediment of the pleural fluid demonstrated RBCs in the background and a small number of neutrophils, and it was negative for malignancy. All cultures and stains for bacteria, including for mycobacteria and fungi, were negative.