Paraneoplastic Dermatoses and Cutaneous Metastases

Paraneoplastic syndromes include a variety of cutaneous presentations that have an associated internal malignancy. Some syndromes have a strong correlation to specific internal malignancies, whereas others are associated with a multitude of tumors. There are many cutaneous manifestations that suggest hematologic disorders, which will be reviewed in detail. Cutaneous metastases are commonly from breast and lung cancers and can present as nodules, vascular lesions, eczematous dermatitis, or inflammatory lesions. The most common histologic presentation of cutaneous metastasis is that of a dermal-based or subcutaneous-based nodule with sparing of the epidermis. Determination of origin of tumor requires immunohistochemistry and clinical correlation.