Abstract: Bowen's disease is a type of squamous cell carcinoma in situ of the skin. The pigmented form is rare and represents less than 2% of cases. We report a case of a 74-year-old black man with a blackened and asymptomatic leg injury for about 6 months. Clinically, and under dermatoscopy, the injury was suggestive of melanoma or melanoacanthoma, and a definitive diagnosis was made by histopathological examination.

Abstract Woolly hair nevus is a rare condition characterized by a structural anomaly of the hair, restricted to certain areas of the scalp. The hair becomes coiled and slightly hypopigmented. The term woolly hair refers to changes that affect all the scalp and has a hereditary character. We present a case of woolly hair nevus, that developed at the age of 2 years, associated with dental diastema and verrucous epidermal nevus.

Abstract Perforating dermatoses are a group of skin diseases characterized by transepidermal elimination of dermal material. The disease is divided into two groups: the primary group and the secondary group. The classical or primary perforating dermatoses are subdivided into four types according to the eliminated dermal materials: Kyrle disease, perforating reactive collagenosis, elastosis perforans serpiginosa, and perforating folliculitis. The secondary form is known as acquired perforating dermatosis. The term was proposed in 1989 by Rapini to designate the perforating dermatoses affecting adult patients with systemic disease, regardless of the dermal materials eliminated. This report describes a case of the disease with elimination of collagen and elastic fibers in a patient with chronic renal failure.

A doença de Cowden ou síndrome dos hamartomas múltiplos é de transmissão autossômica dominante cuja tríade dermatológica compõem-se de triquilemomas faciais múltiplos (hamartomas do infundíbulo folicular), fibromas orais e queratoses acrais benignas. A importância desta doença está no aumento da susceptibilidade a malignização de algumas lesões, especialmente de mama, tireóide e trato genito-urinário. Apesar da expressão fenotípica variada, esta doença é geralmente desconhecida. Consequentemente, muitos casos não são diagnosticados ou o diagnóstico vem tardiamente, o que ressalta a importância do diagnóstico precoce da doença para que o paciente possa ser monitorado periodicamente para diagnóstico e tratamento precoce de doenças malignas.

Cowden's disease or multiple hamartoma syndrome is an autosomal dominant inherited disease and the main dermatological features are facial trichilemmomas (hamartomas of the follicular infundibula), oral fibroma and benign acral keratoses. The importance of this disease lays in the increased susceptibility to malignization of some lesions, especially breast, thyroid and genitourinary tract. Despite its varied phenotypic expression, this disease is generally unknown. Consequently, many cases are undiagnosed or diagnosis comes at a late stage, which reinforces the importance of an early investigation of the disease so the patient may have periodic check-ups to discover and treat malignancies.