Necrobiose lipoídica em adolescente com diabetes mellitus tipo 1: relato de caso

***Necrobiosis lipoidica in an adolescent with type 1 diabetes mellitus: case report***AIMS: To report a case of necrobiosis lipoidica, a rare chronic granulomatous dermatosis.CASE DESCRIPTION: We present the case of a 17-year-old male adolescent, with type 1 diabetes mellitus from the age of four, followed in the Pediatric-Diabetology clinics of a level II hospital, under intensive regimen with multiple insulin administrations and poor metabolic control. At the age of 15, he noticed the appearance of an asymptomatic, erythematous, infiltrated, oval-shaped plaque, with a waxy whitish center, well-defined borders, 5 cm in diameter and progressive growth, located on the left forearm. The histological examination confirmed the diagnosis of necrobiosis lipoidica. He was treated with topical corticosteroid and emollient, thus stabilizing and reducing lesion infiltration.CONCLUSIONS: The authors highlight a rare dermatosis, non-pathognomonic of diabetes mellitus but related to this diagnosis in most cases. Its challenging recognition, especially in the presence of recent onset lesions, with atypical clinical presentation or in unusual sites, is fundamental in order to avoid erroneous or late treatments and its progression to ulceration.