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.
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.
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.
Actinic keratosis (AK) is defined as a pre-cancerous lesion. Its prevalence is proportional to ultraviolet radiation exposure and age, predominantly affects male gender (55% in men vs 37% in women). 1 Clinically, AK is characterized by multiple erythematous or hyperkeratotic papules located in areas exposed to high solar radiation, such as head, neck, or upper extremities. Most lesions are asymptomatic. 2 In 1991, Olsen et al has described a clinical classification, dividing AK into grades I, II, and III. Grade I describes lesions more palpable than visible, while grade II refers to those which are easily visible as well as palpable, and grade III corresponds to the thicker and more keratotic ones. 3 It is estimated that the rate of transformation from an AK into a squamous cell carcinoma (SCC) is 0.1%-20% per lesion. 4 The
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