[Muscle metastasis revealing bronchial adenocarcinoma]

The diagnosis of nonsmall cell lung cancer is made at a metastatic stage in 25% of cases. The most frequent sites are the lung, liver, bone, the adrenal glands and the central nervous system. Skeletal muscle metastases are uncommon and are rarely the first manifestation of a neoplastic process.

We report the case of 55 years old man presenting with a hard painless swelling of the left arm. A scan guided biopsy revealed infiltration of the muscle by a thyroid transcription factor 1 (TTF1) positive adenocarcinoma. A CT scan of the chest showed a partially necrotic tissue mass with moderate uptake of contrast. The patient was treated by chemotherapy with gemcitabine and carboplatine. The progress was unfavourable with the appearance of a second muscular metastasis in the thigh and the patient died 3 months after diagnosis.

Skeletal muscle metastases are rarely described in lung cancer and they are an exceptional presentation of the tumour. Their symptoms can be misleading and delay diagnosis.