Cutaneous Metastasis as the First Presentation of Non-Small-Cell Lung Cancer with a BRAF Mutation: A Case Report

Cutaneous metastasis from a primary visceral malignancy is a relatively uncommon clinical manifestation that occurs as an initial presentation in 1% to 12% of patients with internal malignancies. Additionally, cutaneous metastases are often late signs of an internal malignancy, and in very rare cases they may occur at the same time or before the primary cancer has been detected. Metastasis to the skin has a poor prognosis and is often a sign of widespread malignant tumors. In the present study, we report a 72-year-old male who presented with multiple rapidly growing subcutaneous nodules. Positron emission tomography-computed tomography (PET-CT) revealed a hypermetabolic concentration of radiotracer in the left lower lung and multiple organ metastases associated with multiple skin masses. Biopsy of one of the skin nodules and gene detection indicated metastatic adenocarcinoma consistent with a primary lung origin with a BRAF mutation. BRAF mutations are emerging therapeutic targets in non-small-cell lung cancer (NSCLC), as they are present in 2-4% of NSCLC cases. To the best of our knowledge, this is the first case report to show that BRAF-mutant lung adenocarcinoma can be associated with cutaneous metastasis. Early diagnosis and individualized treatment strategies may prolong patient survival.