Abstract Appearance of a dermatosis with a potential paraneoplastic association may herald the appearance of a new or relapsed neoplasm, and may in some cases even provide the clue to the type of cancer present. However, it should be kept in mind that while the mucocutaneous paraneoplastic syndromes discussed herein occur primarily in hematologic diseases, they still may be associated with solid tumors on occasion (Table IV). 4,49,50 As more is learned about the causes of these syndromes, paraneoplastic phenomena may shed light on the biology of specific cancers. Based on the diverse nature of the paraneoplastic mucocutaneous syndromes, a uniform etiologic basis is unlikely and, to date, a variety of possible immune- or cytokine-mediated aberrations have been postulated. In regard to treatment, some of the cutaneous paraneoplastic syndromes will respond to specific measures such as systemic corticosteroid therapy but, for the most part, successful resolution requires eradication of the underlying malignancy.