title: Metastatic squamous cell carcinoma presenting as an erythematous nodule in a man with lung adenocarcinoma.
abstract: Skin metastases from visceral malignancies have been well documented in the literature, and may be the presenting sign of an occult internal malignancy. Lung cancer in particular is a relatively common cause of skin metastases, which are considered a poor prognostic sign. Rarely, patients with lung cancer develop a second primary lung cancer that may require a novel chemotherapeutic regimen. The frequency of second primary malignancies presenting with metastatic skin lesions is not documented in the literature. We present a case of a 50-year-old man with a history of metastatic lung adenocarcinoma who was referred for evaluation of a nodule overlying his right mandible, which had been progressively enlarging for two weeks. Biopsy demonstrated metastatic squamous cell carcinoma. Subsequent CT-guided biopsy of a left retroperitoneal lymph node was conducted and notable for squamous cell carcinoma. Therefore, this patient's skin lesion was the presenting sign of a second primary visceral tumor, likely originating in the lung. We present this case to raise clinical awareness of the rare phenomenon that cutaneous metastasis may be the first sign of a visceral cancer, even in the setting of a previous distinct primary malignancy.
authors.forename: Dorota Z
authors.initials: DZ
authors.lastname: Korta
authors.forename: Jesse M
authors.initials: JM
authors.lastname: Lewin
authors.forename: Shane A
authors.initials: SA
authors.lastname: Meehan
authors.forename: Sarika M
authors.initials: SM
authors.lastname: Ramachandran
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D001706:Biopsy; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000473:pathology* / Q000556:secondary; D004890:Erythema / Q000473:pathology; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000556:secondary