CT and PET/CT findings of primary pulmonary malignant melanoma: a case report and literature review

Primary malignant melanoma of the lung (PMML) is an extremely rare and refractory tumor, and its diagnosis is a significant challenge. The current study presents the case of a 62-year-old man who presented to the Department of Cardiothoracic Surgery (Lishui Municipal Central Hospital, Lishui, China) with chest tightness and fatigue for 3 months. Chest computed tomography (CT) revealed a 1.5- × 1.9-cm mass with irregular borders and heterogenous density located in the right lower lung lobe. Contrast-enhanced CT revealed slight enhancement of the mass, but there was no clear evidence of malignancy. Positron emission tomography (PET)/CT revealed a defined-margin mass, with slightly high uptake (standardized uptake value [SUV]: 3.6). The patient underwent video-assisted thoracoscopic surgery (VATS), and the final diagnosis was PMML on the basis of the results of the pathological examination. The patient received four courses of immunotherapy after the operation, and eventually declined further immunotherapy owing to the high cost. The patient was followed-up for 1 year without metastasis or recurrence.