Ipsilateral Hyperhidrosis: Atypical Symptom of Small Lung Adenocarcinoma Evaluated by 18F-FDG PET-CT.

A 45-year-old male visited our clinic due to right palmar anhidrosis and contralateral hyperhidrosis. Chest computed tomography (CT) showed a solitary pulmonary nodule with mediastinal lymph node enlargement, but a cause for atypical palmar anhidrosis was not identified. Subsequent fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed (PET/CT) revealed a localized pleural metastasis at the right apex with direct invasion of the paravertebral sympathetic chain. The pleural metastasis, which was not seen on chest CT, evoked ipsilateral anhidrosis independent of a mass effect or direct invasion by the primary lung tumor. 18F-FDG PET/CT can be helpful in identifying the cause of atypical symptoms in patient with small sized lung cancer.