Necrobiosis lipoidica and granuloma annulare. Simultaneous occurrence in a patient

Necrobiosis lipoidica (NL) and granuloma annulare (GA) occurred simultaneously in a patient with diabetes. Staining with colloidal iron showed deposition of acid mucopolysaccharides in the GA lesions and the absence of acid mucopolysaccharides in the NL lesions. If the two diseases have a common cause, that being the necrobiotic process, then one would expect to encounter their simultaneous occurrence much more frequently.