Paraneoplastic syndromes are localized or diffuse pathologic manifestations that may occur in subjects affected by neoplastic diseases, even occult ones. Among the many clinical manifestations of paraneoplastic syndromes, cutaneous ones are quite common. It is estimated that skin manifestations may represent the very first diagnostic sign of a neoplastic disease in about 1% of patients. Many paraneoplastic syndromes with skin manifestations are caused by vascular alterations. In case of solid tumors, migrant thrombophlebitis and blood hypercoagulability can be seen, whereas in case of hematological neoplasms, vasculitis, and erythromelalgia can occur. Paraneoplastic vasculitis and paraneoplastic vascular syndromes are challenging issues in dermatology and general medicine. The present article will review the actual knowledge in the argument, together with providing hints for its diagnosis and management.