Abstract: Psoriasis is a chronic disease, characterized by erythematous scaly lesions, presented in eight different forms: plaques, guttate, pustular, erythrodermic, inverse, nail and scalp psoriasis, and psoriatic arthritis. Its development depends on genetic factors, external stimulus and immune response alteration.1 Proinflammatory cytokines such as TNF-alpha, IL-12 and 23 may also be involved. In the worst cases, systemic complications linked to endothelial alterations may occur. A literature review was conducted for a better understanding of what roles VEGF (vascular endothelial growth factor) and ICAM-1 (intercellular adhesion molecule) have, among other cytokines, in systemic capillary leak syndrome, involved in erythrodermic and pustular psoriasis, the most unstable forms of the disease.

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: Kaposi's sarcoma (KS) is a multicentric vascular neoplasm, with cutaneous and extracutaneous involvement. Different clinical and epidemiological variants have been identified. The classic form is manifested mainly in elderly men with indolent and long-term evolution, with lesions localized primarily in the lower extremities. We present two cases of classic Kaposi's sarcoma (CKS) in two female patients with extensive, exuberant skin involvement and rapid evolution, with good response to radiotherapy.

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.