Lung Adenocarcinoma with Chronic Lymphocytic Leukemia Mimicking Bone Metastasis

A 77-year-old man was referred to our hospital for abnormal thoracic radiographs. Computed tomography (CT) revealed a 20-mm subpleural ground-glass opacity in the right S⁶ area. A CT-guided biopsy revealed lung adenocarcinoma. Fluorodeoxyglucose-positron emission tomography revealed multiple abnormal bone accumulations, and a subsequent biopsy of a left iliac bone lesion revealed chronic lymphocytic leukemia. A right lower lung lobectomy was performed for the lung adenocarcinoma (cT1bN0M0, stage IA2). An aggressive biopsy of the bone lesion confirmed a rare case of double primary malignancies, which determined the patient's treatment and outcomes.