Introduction Melanoma origin has always been a debated subject, as well as the role of adjacent melanocytic nevi. Epidemiological and histopathological studies point to melanomas arising either de novo or from a nevus. Methods Sixty-one melanomas found in association with a preexisting nevus were microdissected, after careful selection of cell subpopulations and submitted to Sanger sequencing of the BRAF, NRAS, C-KIT, PPP6C, STK19 and RAC1 genes. Each gene was evaluated twice in all samples by sequencing or by sequencing and another confirmation method, allele-specific fluorescent polymerase chain reaction (PCR) and capillary electrophoresis detection, or by SNaPshot Analysis. Only mutations confirmed via two different molecular methods or twice by sequencing were considered positive. Results The majority of cases presented concordance of mutational status between melanoma and the associated nevus for all 6 genes (40/60; 66.7%). Nine cases presented concomitant BRAF and NRAS mutations, including one case, in which both the melanoma and the adjacent nevus harbored V600E and Q61K double mutations. In two cases, both melanoma and associated nevus, located on acral sites were BRAF mutated, including an acral lentiginous melanoma. Conclusions This is the largest nevus-associated melanoma series molecularly evaluated to our knowledge. The majority of melanomas and adjacent nevi in our sample share the same mutational profile, corroborating the theory that the adjacent nevus and melanoma are clonally related and that melanoma originated within a nevus.

Unilateral peripheral facial nerve palsy jeopardizes quality of life, rendering psychological consequences such as low self-esteem, social isolation, anxiety, and depression. Among therapeutical approaches, use of Botulinum toxin type A (BoNT-A) on the nonparalyzed side has shown promising results and improvement of quality of life. Nevertheless, the correct technique is paramount, since over-injection of the muscles can result in lack of function, leading to a “paralyzed” appearance, and even worse, functional incompetence, which may cause greater distress to patients. Therefore, the objective of this article is to provide a practical guideline for botulinum toxin use in facial palsy. To this aim, adequate patient assessment, BoNT-A choice, injection plan and dosage, and injection techniques are covered.

The aim of this study was to evaluate the practical importance of the presence of shiny white streaks (SWS) (chrysalis or crystalline structures in polarized dermoscopy) for suspicion of malignancy, diagnosis of melanoma, and pre-operative estimation of Breslow thickness and its correlation with total dermoscopy score (TDS). SWS were present in 13.6% of 800 consecutive excised lesions. The presence of SWS was associated with malignancy (odds ratio (OR) 10.534, 95% confidence interval (95% CI) 6.357-17.455, p < 0.0005) in the context of melanocytic lesions with invasive melanoma (OR 10.333, 95% CI 3.812-28.014) and melanomas with high TDS (OR 6.286, 95% CI 1.673-23.619), but was also a factor in the diagnosis of featureless and some thin melanomas. These results corroborate the clinical applicability of SWS in aiding the diagnosis of malignancy and helping to raise the general dermatologist's awareness in cases of doubt and featureless lesions.

In order to determine dermoscopic parameters, a case-control test set of naevus-associated melanomas vs de novo melanomas paired by Breslow thickness and histopathological subtype was analysed by 2 blinded experienced dermoscopists, according to presence of naevus, pattern analysis and ABCD dermoscopy score. The ability to identify naevus-associated melanomas by pattern analysis was low for both blinded dermoscopists (κ < 0.2). Dermoscopy features associated with naevus-associated melanomas were: presence of negative pigment network (OR 9.915, CI 95% 2.182-45.049), globules (OR 2.383, CI 95% 1.15-4.95) and streaks (OR 2.439, CI 95% 1.271-4.680). In contrast, the presence of blue-white veil was related to absence of associated naevus (OR 0.520, CI 95% 0.273-0.991). With the results obtained, 2 different algorithms were proposed. The use of the proposed algorithms could help raise awareness of naevus-associated melanomas and avoid the possibility of incorrectly diagnosing a naevus-associated melanoma if partial biopsies are performed.