Biceps Brachii Metastasis as the Initial Clinical Manifestation of Lung Squamous Cell Carcinoma: A Potential Pitfall in Patients With Nonrespiratory Symptoms.

Metastatic tumor in the biceps brachii as the initial manifestation of non-small cell lung cancer is exceedingly atypical. Herein, we present the case of a 69-year-old woman with a left biceps brachii mass as the initial presentation. 18 F-FDG PET/CT revealed a lesion in the upper lobe of the left lung and the left biceps brachii mass with SUV max of 9.9 and 14.1, respectively. Ultimately, histopathologic examination following biopsy confirmed lung squamous cell carcinoma with metastasis to the biceps brachii. Our case highlights the notable strength of PET/CT in identifying the primary lesion site in patients with atypical clinical manifestations.