[Perforating necrobiosis lipoidica].

This is the case history of a woman with a 6 year history of insulin-dependent diabetes mellitus and a 5 year history of tuberous lesions on the dorsal aspect of the metacarpophalangeal joints. Histological examination revealed multiple necrobiotic foci throughout the dermis and subcutaneous tissue, with varying degrees of degeneration, alternating with fibrotic areas. This picture is compatible with lipoid necrobiosis. The existence of various foci of epithelial perforation, manifested clinically by a point hyperkeratosis similar in appearance to blackheads, suggests transfollicular elimination. This would explain the total absence of a pilosebaceous follicles in the lesion.