Cutaneous Metastasis from Lung Adenocarcinoma.

Cutaneous metastases are rare and often portend the aggressive malignancy and poor prognosis. We report a case of a 62-year-old man with a rapidly growing nodule on the left back for 2 months. The patient was diagnosed with lung adenocarcinoma shortly before the skin lesion presented. Physical examination showed a dome-shaped purplish red nodule, with ulceration and hemorrhagic crust. Excision of the skin lesion was performed, and the histopathology showed tumor cells infiltrate with immunohistochemistry (TTF-1+CK7+CD20-) favoring primary lung adenocarcinoma.