Abstract Pemphigus herpetiformis is an autoimmune bullous disease, that combines clinical features of dermatitis herpetiformis and linear IgA bullous dermatosis and immunological characteristics of pemphigus, which makes this disease peculiar and this diagnosis rarely suspected in the first evaluation of the patient. The reported case is of a patient with clinically bullous disease similar to dermatitis herpetiformis, whose multiple biopsies were inconclusive, and only after direct immunofluorescence with a pemphigus pattern (intraepidermal intercellular pattern) the confirmation of the diagnosis was possible.

Abstract Darier's disease is a rare autosomal dominant genodermatosis. It has an estimated prevalence of 1 in 55,000 to 100,000 individuals, regardless of gender. It is characterized by multiple keratotic papules on the seborrheic areas of the trunk, scalp, forehead and flexures, and the clinical picture is worsened by heat, sun exposure, perspiration and mechanical trauma. Histopathology observed loss of epithelial adhesion and abnormal keratinization. About 10% of cases present in the localized form of the disease. We report a case of segmental Darier's Disease Type I and discuss the main characteristics of this condition.

Abstract Collision tumors are characterized by the coexistence of two cancers in the same anatomical site and its pathogenesis remains controversial. Although uncommon, the association of basal cell carcinoma and melanocytic nevus is the most common among combinations of skin tumors. Even rarer is the association of two malignant tumors. We report a case of tumor collision representing melanoma and basosquamous cell carcinoma, a combination not previously described in the literature, since there are no reported cases of melanoma with this type of basal cell carcinoma.