Necrobiosis lipoidica diabeticorum is a cutaneous disorder which often presents a vivid diagnostic picture. The lesions consist of round, oval, or irregular well-defined firm plaques, yellow at the center, violaceous at the periphery, usually located on the lower extremities, but may occur elsewhere. Later, the center becomes depressed and atrophic because of tissue destruction, and in certain instances ulceration may supervene. In a small percentage of cases, the cutaneous lesions may precede any evidence of a metabolic disturbance. In 90% of the cases, however, the cutaneous lipoidosis is generally associated with diabetes mellitus; it may almost be said that necrobiosis lipoidica diabeticorum is a cutaneous manifestation of diabetes mellitus. Many internists firmly believe that intercapillary glomerulosclerosis, or the Kimmelstiel-Wilson syndrome, is a nephritic expression of an underlying diabetes mellitus. The syndrome consists of diabetes mellitus, nephritic edema, gross albuminuria, and hypertension. Surveys of a series of