Skin metastasis from typical carcinoid tumor of the lung

Carcinoids are neuroendocrine tumors that may arise within any organ, although they are more commonly found in the gastrointestinal tract and in the bronchopulmonary tract. They are generally characterized by an indolent clinical course but may in some instances metastatise to regional lymph nodes or to distant sites. We herein describe a rather infrequent case of a 60-year-old man with a skin metastasis from a typical carcinoid of the lung. We discuss the histopathological and immunohistochemical features in the context of previous literature and comment issues related to difficulties in the differential diagnosis. Dermatopathologists should be familiar with the metastatic carcinoid profile in order to avoid potential misdiagnoses and to properly address the patient management when the skin metastasis represents the first manifestation of an internal disease.