An 81-year-old man living in South Korea was referred to the pulmonology clinic because of abnormal findings at routine surveillance CT (Fig 1A, 1B). His past medical history included right radical nephroureterectomy for ureteral cancer in 2016, transurethral resection of a bladder tumor in 2015, and tuberculous pleurisy in his third decade of life that was complicated by a chronic calcified empyema (Fig 1C). He had been doing well clinically until 6 months prior, when he presented to an outside hospital with progressive right-sided chest pain and dyspnea and was found to have active tuberculosis. During that hospitalization, he underwent chest CT and CT-guided biopsy of an incidentally found thoracic lesion (Fig 2), which revealed chronic active inflammation. His symptoms improved after initiation of antituberculous medication, and he was discharged home to complete treatment. Because of interval growth of this lesion noted on a subsequent surveillance CT scan, he was referred to pulmonology for further evaluation. Laboratory tests obtained during his visit revealed mild leukocytosis (1258 cells × 109/L; normal range, 4000–10 000 cells × 109/L) with neutrophilic predominance (82% neutrophils; normal range, 50%–75% neutrophils), and a mildly elevated C-reactive protein level (3.17 mg/dL; normal range, 0–0.5 mg/dL). A sputum culture was negative for tuberculosis. The patient reported mild chest discomfort and dyspnea. Liver MRI was performed to further evaluate an abnormal lesion seen at CT (Fig 3). Given the patient’s recent nonspecific biopsy results and tuberculosis treatment, no further work-up was pursued. Contrast-enhanced chest CT was performed 6 months later because the patient developed worsening chest pain and dyspnea (Fig 4). He remained afebrile, with persistent leukocytosis (1485 cells × 109/L) and an elevated Creactive protein level (3.56 mg/dL). On the basis of the imaging findings, repeat CT-guided biopsy and PET/CT were performed (Fig 5), thereby enabling confirmation of the diagnosis, and appropriate treatment was initiated.Unenhanced surveillance CT of the abdomen revealed masslike soft tissue arising from the diaphragm adjacent to a chronic calcified empyema (Fig 1A), and a lowattenuation lesion within the right hemiliver (Fig 1B). These lesions were not present on previous surveillance abdominal CT scans (Fig 1C). There was no thoracic lymphadenopathy or erosive changes of the adjacent ribs. Contrast-enhanced chest CT performed 6 months prior at an outside hospital revealed a peripherally enhancing thoracic lesion located eccentrically along the margin of the empyema (Fig 2A). CT-guided biopsy images showed the biopsy needle tip targeting the lesion (Fig 2B). This multilobular thoracic lesion was found on liver MRI scans to have increased in size, with extension into hepatic segment 7 (Fig 3D). The lesion exhibited predominantly hyperintense signal centrally and a hypointense rim on heavily T2-weighted images (Fig 3A, 3B), peripheral enhancement on portal venous phase images (Fig 3C), and heterogenous diffusion restriction (Fig 3E, 3F). A chest CT study obtained 6 months later revealed further growth of this pleural-based mass (Fig 4) that was concerning for progression of malignant disease. Fluorodeoxyglucose (FDG) PET/CT showed intense FDG uptake at the mass (maximum standardized uptake value, 26) (Fig 5). No other hypermetabolic lesions were evident. What is your diagnosis?