Squamous cell carcinoma of the lung with simultaneous metastases to peritoneum and skeletal muscle.

Skeletal muscle and peritoneum are rare sites of metastases from lung cancer. We report a case of squamous cell lung cancer with concurrent metastases to skeletal muscle and peritoneum. A 71-year-old man was diagnosed with squamous cell carcinoma of the right lower lobe with metastasis to the right hilar lymph node at clinical stage T3N1M0. Because of poor performance status and comorbidity, he only received radiation therapy. Positron emission tomography-computed tomography for mid-assessment of response showed two abnormal hypermetabolic lesions in the peritoneum of the left upper quadrant area and the left thigh muscle. We performed a needle-approach biopsy in each lesion and found both of the lesions were metastases from lung cancer. The patient died after two months.