[Soft tissue metastasis revealing an asymptomatic bronchial adenocarcinoma]

Skeletal muscle metastases from non-small-cell lung cancer are uncommon. We report a case of lung adenocarcinoma disclosed by metastatic dissemination to a forearm muscle. A 46-year-old man consulted for a painful mass of the right forearm. Ultrasonography and computed tomography revealed a heterogeneous collection in the forearm invading the cortex of the humerus. An excisional biopsy of the right forearm showed an infiltration of the muscle with metastatic adenocarcinoma. Immunohistochemical patterns suggested the pulmonary origin. Chest x-ray was normal. Bronchoscopy revealed an endobronchial mass that was confirmed by biopsy to be an adenocarcinoma. The lung tumor was staged T2N0M1. The patient has received local radiation therapy and chemotherapy. After eighteen months, the disease progressed but without local muscular recurrence. Skeletal muscle metastases from lung cancer are rare and although their prognosis is poor, local treatment may be worthwhile.