Abstract Background: Dermoscopy increases the sensitivity of the diagnosis of melanoma, leading to its early identification and increasing the chances of cure. Objective: To describe the clinical and dermoscopic characteristics of superficial spreading melanomas, and to detect the differences between in situ and invasive 1-mm thick melanomas. Methods: This was a cross-sectional study in which dermoscopic images of 58 melanomas, grouped according to their thickness, were evaluated. Results: 24 in situ melanomas were evaluated, 28 invasive melanomas with Breslow ≤ 1 mm (0.50 ± 0.22 mm) and six with Breslow > 1 mm (2.35 ± 2.02 mm). In situ melanomas were smaller than invasive melanomas. The most commonly found dermoscopic criteria were asymmetry (84.5%), three or more colors (81.0%), and atypical network (79.3%). A non-specific pattern was more common in in situ melanomas (p = 0.028) and atypical network in invasive melanomas with Breslow 1 mm presented inverted network (p = 0.018). Study limitations: The sample was selected by convenience, since it was necessary to have a preoperative photo of the tumor, which may have led to the loss of clinically less significant lesions, as well as those highly suggestive of melanoma. Conclusions: Melanomas in early stages showed a more frequent nonspecific pattern and atypical network, while invasive melanomas showed a multicomponent pattern, three or more colors, and an inverted network.

Abstract The etiology of pityriasis lichenoides is unknown. One of the accepted theories admits that PL is an inflammatory response to extrinsic antigens such as infectious agents, drugs and vaccines. In recent medical literature, only the MMR vaccine (Measles, Mumps and Rubella) was associated with the occurrence of this disease. We present a case of a male, 12 year old healthy patient who, five days after Infl uenza vaccination, developed erythematous papules on the trunk, abdomen and limbs, some with adherent crusts and associated systemic symptoms. This case report is notable for describing the first case of pityriasis lichenoides et varioliformis acuta associated with the vaccine against Influenza.