Primary macroglobulinemia presenting as multiple ulcers of the legs.

Multiple ulcers developed on the lower legs of a 67-year-old man suffering from macroglobulinemia. Histological and direct immunofluorescence studies on biopsy specimens taken from the lesions revealed dilation of capillaries, deposition of large quantities of IgM in the vessels, and deposition of C3 in the vessel walls. A marked increase in blood Clq binding immune complexes was also noted. These findings suggest immune complex-induced ulceration. The fact that IgM-type cryoglobulins were positive implies that cryoglobulins derived from macroglobulins may play an important causative role in ulceration.