Elastosis perforans serpiginosa is a rare, primary perforating dermatosis, frequently associated with certain genetic diseases and characterized by the transepidermal extrusion of elastic fibers. The present case report describes this dermatosis in a 19-year old female patient with Down's syndrome, who presented with asymptomatic erythematous, keratotic papules in an arciform pattern, located on her right forearm and knee, which had been present for five years. Following histopathological confirmation, treatment with cryotherapy was initiated, resulting in partial remission of the lesions. Keywords: Conjunctive tissue; Down's syndrome; Elastic tissue; Elastic tissue abnormalities Resumo: A elastose perfurante serpiginosa é dermatose perfurante primária incomum, frequentemente associada a determinadas doenças genéticas e caracterizada por eliminação transepidérmica de fibras elásticas. Relata-se um caso raro dessa dermatose em paciente feminina de 19 anos, portadora da sín-drome de Down, que apresentava pápulas eritematoceratóticas em arranjo arciforme, localizadas no antebraço e joelho direitos, assintomáticas, com cinco anos de evolução. Após confirmação histopatológica, foi iniciado tratamento com crioterapia, ocorrendo remissão parcial das lesões.

Becker´s nevus is a hyperpigmented macula that is predominantly located on the anterior trunk or on the scapular region, frequently associated with hypertrichosis. The association of Becker´s nevus with other cutaneous, musculoskeletal or maxillofacial anomalies has been called Becker´s nevus syndrome. We report a case of a 16-year-old girl with a hyperpigmented macula which spread from her right anterolateral trunk to the inner part of her right thigh accompanied by ipsilateral mammary hypoplasia. The skin lesion started when the patient was seven years old when it was also noticed ipsilateral mammary hypoplasia. The histological exam confirmed the clinical hypothesis of Becker´s nevus. Keywords: Breast; Breast/abnormalitites; Hamartoma; Pigmented nevus; Smooth muscle Resumo: O nevo de Becker se manifesta como uma mácula hipercrômica, localizada predominantemente no tronco anterior ou região escapular, e frequentemente associada à hipertricose. A coexistência do nevo de Becker e anormalidades cutâneas, músculo-esqueléticas ou maxilo-faciais corresponde à síndrome do nevo de Becker. Relata-se o caso de uma paciente de 16 anos, portadora desde os sete anos de mácula hipercrômica, localizada no tronco ântero-lateral direito, estendendo-se até a face medial da coxa direita, acompanhada de hipoplasia mamária ipsilateral. O exame anatomopatológico confirmou a hipótese clínica de nevo de Becker.