Gastric Metastasis Masquerading as a Polyp in Lung Adenocarcinoma: A Rare Presentation on ¹⁸ F FDG PET/CT

Gastric metastasis from lung carcinoma is a rare finding. It is often clinically unsuspected and may mimic primary gastric malignancy. We report a rare case of primary lung adenocarcinoma with gastric metastasis presenting as a polyp. ¹⁸ F fluorodeoxyglucose (FDG) PET/CT demonstrated an FDG-avid right lung primary lesion with nodal, serosal, and intracranial metastases, along with an FDG-avid intraluminal gastric polypoidal lesion. Histopathological examination confirmed lung adenocarcinoma with metastatic involvement of the stomach. This case highlights an atypical metastatic pattern of lung adenocarcinoma.