Paraneoplastic vasculitis. Unique syndrome of cutaneous angiitis and arthritis associated with myeloproliferative disorders.

Six patients are described whose myeloproliferative disorders were complicated by inflammation in small, predominantly cutaneous blood vessels. The clinical manifestations of the vasculitis included palpable purpura, urticaria, maculopapular lesions, and erythema multiforme. Vascular inflammation was confirmed by skin biopsy. Two patients experienced fleeting, asymmetrical nondestructive arthritis. Transient proteinuria complicated one case and was the only suggestion of visceral vasculitis. The clinical features of cutaneous vasculitis antedated bone marrow deterioration in four patients and diminished as bone marrow function worsened in all patients. Oral corticosteroids or chemotherapy for the underlying disorder inconsistently affected the clinical course of the cutaneous vasculitis. Myeloproliferative disorders should be considered among disorders that are complicated by inflammation in small blood vessels.