Cutaneous manifestations of internal malignancy.

The skin often mirrors changes in the organism it envelops. Many neoplastic diseases that affect internal organs display cutaneous manifestations, which may be the presenting signs and symptoms of the underlying malignancy. These may reflect direct involvement of the skin by the tumor (ie, tumor metastasis) or indirect involvement, in which changes in the skin occur in the absence of malignant cells. This review focuses on the latter conditions, which are often referred to as paraneoplastic dermatoses. Included in the discussion are the cutaneous manifestations of inherited syndromes that are associated with an increased risk of internal malignancy, cutaneous changes in patients with hormone-secreting tumors, and the wide spectrum of proliferative and inflammatory dermatoses that have been associated with internal cancer.