Neoplastic and paraneoplastic vasculitis, vasculopathy, and hypercoagulability.

It is essential to be aware of both neoplastic and paraneoplastic vasculitides, vasculopathy, and hypercoagulability, considering the importance of an accurate diagnosis and timely treatment of the underlying malignancy. Characteristics such as the type of vasculitis, age, gender, atypical presentation, and lack of response to common therapies should prompt investigation for an occult malignancy, whereas vasculitis such as GPA require due malignancy vigilance given a significantly increased risk of malignancy at the time of diagnosis and in the following years. Vasculopathies are rarer than vasculitides, but are associated with specific malignancies and, in the context of such malignancies, should be kept in mind. Hypercoagulability is a well-documented neoplastic phenomenon with an increased risk of thrombosis in the setting of positive aPLs. Most neoplastic and paraneoplastic vascular syndromes require no specific treatment outside of treatment of the underlying malignancy. The two key exceptions are PACNS, because of its poor prognosis, and erythromelalgia, in which aspirin is an effective agent.