Forearm Skin Capillaries of Diabetic, Potential Diabetic and Nondiabetic Subjects: Changes Seen by Light Microscope

Light microscopic examinations were carried out on sections of skin from thirty diabetic and 101 control subjects. Examination of the periodic acid-Schiff stained material in a blind study revealed an abnormality in sixteen of the thirty diabetics and seven of the 101 controls. The abnormality is a hyalinization of the normally fibrillar area external to the endothelial cell of the dermal capillaries. Among the diabetics, the abnormality was seen more frequently in juvenile diabetes, long-standing diabetes, diabetes with retinopathy, neuropathy, or nephropathy, and in obese diabetics. The incidence in control subjects was not strikingly higher in those with a family history of diabetes (three in thirty-nine) or in acromegaly (one in eleven) than in other control subjects (three in fifty-one). Electron microscopic observations suggest that the lesion may be due to deposition of material in the collagen containing cuff of the capillary wall rather than to basement membrane thickening.