Metastasis of lung cancer to the skin is uncommon, presenting in 0.22% to 12% of lung cancer patients, and it is extremely rare for skin metastasis to be the first clinical manifestation of lung cancer. In the few cases where skin metastasis has been reported as the first sign of lung cancer, the patients were typically heavy smokers or had preexisting respiratory diseases and symptoms. This prompted clinicians to consider skin metastasis of a pulmonary malignancy. Large cell neuroendocrine carcinoma (LCNEC) is a rare type of lung cancer that accounts for approximately 3% of lung cancers. LCNEC mainly metastasizes to visceral organs, such as the liver, bone, and brain, and it only shows metastasis to the skin in very rare cases. Herein, we report an unusual case of a metastatic skin lesion as the first sign of primary pulmonary LCNEC, in a 63-year-old woman with no pulmonary symptoms or personal history of smoking or pulmonary disease.
Keywords: Carcinoma; Case reports; Neoplasm metastasis; Neuroendocrine carcinoma; Non-small-cell lung carcinoma.