Obligate and facultative paraneoplastic dermatoses: an overview.

Dermatological paraneoplastic syndromes are a group of cutaneous diseases associated with malignancy, but not directly related to the primary tumor itself or to its metastases. It is of utmost importance for the dermatologist to recognize the major cutaneous paraneoplastic syndromes to diagnose the underlying tumors that trigger them as early as possible. In this overview, skin conditions that are highly correlated with malignancy, whose recognition implies a mandatory investigation of internal cancer, are described.