Multiple nodules on the face and trunk in metastatic adenocarcinoma of unknown primary origin

Metastatic cancer of unknown primary (CUP) may unexpectedly manifest on the skin and subcutaneous tissue, prompting the patient to first visit a dermatologist. We describe an interesting case of cutaneous metastases from poorly differentiated adenocarcinoma of an unknown primary site in a 57-year-old man. The CUP had an unusually long period of indolence between presentation as a solitary axillary lymph node metastasis and rapid cutaneous dissemination. The possible causes of such a presentation are reviewed, and the management is briefly discussed. Diagnosis of unusual cutaneous manifestations of occult systemic malignancies could pose a diagnostic challenge to dermatologists.