Deposits of paraprotein in small vessels as a cause of skin ulcers in Waldenström's macroglobulinemia.

A 71-year-old man presented with epistaxis and large ulcers on arms and legs. A monoclonal IgM-kappa gammopathy and high levels of cryoglobulins were found. Histology of the affected skin showed deposits of paraprotein in the small vessels, causing luminal obstruction. This in turn caused ischemic skin lesions, which were successfully treated with cortisone (fluocortolone 100 mg/day every second day) and cyclophosphamide (100 mg/day).