A 61-year-old male who worked as a frozen chicken processor was referred to us with necrotizing skin ulcers on his hands and feet. Serum IgG and IgA levels were 4,355 mg/dl and 605 mg/dl, respectively. Serum immunoelectrophoresis demonstrated M-bows for anti-IgGλ and anti-IgAκ. Bone marrow aspirate revealed approximately 31% atypical plasma cells. Cryoglobulin was identified in his serum. Cryoglobulin immunoelectrophoresis revealed monoclonal IgGλ paraproteins. The diagnosis was IgGλ type multiple myeloma and concurrent IgAκ type monoclonal gammopathy of undetermined significance with type I cryoglobulinemia. A skin biopsy taken from an involved site showed amorphous eosinophilic material occluding small vessel lumens. There was a good response after one cycle of chemotherapy consisting of vincristine, adriamycin and dexamethasone (VAD). There was a concurrent decrease in serum cryoglobulin levels ; this was associated with re-epithelialization of skin ulcers. Two years later, multiple myeloma progressed during a maintenance therapy of melphalan and prednisolone. Treatment with bortezomib following VAD resulted in a transient response. Serum IgG levels increased to 7,200 mg/dl, in contrast to a decrease in IgA levels to 7 mg/dl. The increase corresponded with the reappearance of skin ulcers. Shortly thereafter, the patient died of multiple myeloma. [J Clin Exp Hematopathol 50(1) : 71-74, 2010]