Multiple myeloma-associated systemic vasculopathy due to crystalglobulin or polyarteritis nodosa.

Systemic vasculopathy is a rare complication of multiple myeloma (MM). We describe a patient diagnosed with MM who developed clinical features of systemic vasculopathy including gangrene, livedo reticularis, hypertension, renal failure, and perforation of the small intestine. Histopathologic examination of the small intestine revealed necrotizing vasculitis in the small arteries, along with crystalline deposits in the small vessels. To our knowledge, previously reported cases of systemic vasculopathy associated with MM include at least 9 cases due to crystalglobulin deposition in vessels and 2 due to polyarteritis nodosa. Deposits of crystalglobulin may have induced systemic necrotizing vasculitis in our patient.