Paraneoplastic dermatoses or cutaneous paraneoplastic syndromes are a non neoplastic skin condition closely related to and in their manifestation directly influenced by an underlying malignancy. They are subdivided into two groups: one whose clinical picture reveals the presence of a malignant tumor and an association with a malign internal tumor in nearly 100%, and a second in which the possibility of a malignancy exists. Not included under the heading paraneoplastic dermatoses are changes with neoplastic cells appearing in the skin, tumors involving secondary illnesses, and genetically caused dermatologic syndromes accompanied by internal malignancies. Although the pathogenesis of the paraneoplastic dermatoses is very unclear, knowledge of these conditions is necessary, since it may in rare instances lead to an early diagnosis of a malignant tumor. On the other hand, only treatment of the underlying disease can improve the dermatoses.