Metastatic Prostate Cancer with Pulmonary Involvement Mimicking Pneumonia: Findings on 18F-FDG PET/CT and 68Ga-PSMA PET/CT.

A 68-year-old man with progressive exertional dyspnea after an upper respiratory tract infection underwent contrast-enhanced thorax computed tomography (CT) to exclude pulmonary thromboembolism. The radiological findings suggested pneumonia or alveolar edema. 18F-Fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET) scan was conducted due to progressive radiological findings. It revealed increased FDG uptake in the prostate gland, mediastinal, abdominopelvic multiple lymph nodes and bilateral lung lesions. 68Ga- prostate-specific membrane antigen-11 (PSMA) PET/CT scan was performed due to low FDG uptake in the lymph nodes and elevated plasma total prostate-specific antigen values. Moderate to high PSMA uptake corresponded to the localizations of FDG uptake on PET/CT. Furthermore, histopathological and immunohistochemical examinations demonstrated that the bilateral lung lesions and bilateral pleural effusion were compatible with metastases from prostate adenocarcinoma.