Abstract

Skeletal muscle metastasis from lung cancer is a rare manifestation that often presents significant diagnostic challenges. We report the case of a 58-year-old man with a 25 pack-year smoking history who was diagnosed with squamous cell carcinoma of the lung following evaluation for a persistent cough. Initial staging revealed no evidence of distant metastasis, and the patient was treated with systemic chemotherapy, achieving stable disease. Nine months later, he presented with a gradually enlarging and painful mass in the right gluteal region. Magnetic resonance imaging demonstrated a cystic intramuscular lesion with mural nodular components located within the gluteus maximus muscle. Ultrasound-guided biopsy confirmed metastatic squamous cell carcinoma, morphologically consistent with the primary lung tumor. The patient was subsequently received second-line chemotherapy.

Key words: Lung Neoplasms, Squamous cell carcinoma, Soft tissue lesions, Gluteus Muscles