Widespread, progressive skin necrosis developed in a 42-year-old male with a 5-year history of osteosclerotic myeloma. Biopsy of the necrotic lesions demonstrated a leucocytoclastic vasculitis with extensive vascular calcification. Radiological investigations demonstrated widespread arterial calcification. Clinical improvement of the established skin lesions followed the institution of a forced calciuresis and parathyroid hormone suppression by induced hypermagnesaemia and phosphate depletion. No further cutaneous necrosis developed. Subsequent treatment with oral immunosuppressive therapy and the diphosphonate, EHDP, has been associated with a complete 18-month remission. The relationship of this apparently unique pathological process to the osteosclerotic myeloma is discussed, together with the rationale for the therapeutic regime instituted.