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Melanocytic nevi, dysplastic nevi, and melanoma are all derived from the pigment-producing cells, namely melanocytes. Concerning the clinical spectrum, cutaneous melanoma is the most aggressive skin cancer with a low survival rate, while nevi are the most common benign lesions in the general population, and dysplastic nevi place in between nevi and melanoma. Ultraviolet (UV) radiation is a well-recognized extrinsic risk factor for all three. BRAFV600E is a well-recognized driver mutation that activates the RAS-BRAF-mitogen-activated protein kinase (MAPK) signaling pathway among 40%–60% of melanoma cases. Interestingly, BRAFV600E mutation is detected even more in acquired nevi, approximately 80%. However, in nevi, several tumor suppressors such as p53 and phosphatase and tensin homolog (PTEN) are intact, and senescence factors, including p15INK4b, p16INK4a, p19, and senescence-associated acidic β-galactosidase, are expressed, leading to cell senescence and cell cycle arrest. Although loss of p53 function is rarely found in melanoma, decreased or loss of PTEN with an activated PI3k/Akt signaling pathway is common in nevi, which may abolish senescence status and allow further progression into dysplastic nevi or melanoma. At present, mouse models closely resembling human nevi are used for investigating these phenomena. Melanocortin 1 receptor deficiency, an intrinsic risk factor for melanomagenesis, is related to the production of procarcinogenic pheomelanin and the inhibition of PTEN function. Immune response escape via programmed cell death-1/programmed cell death ligand-1 interaction plays further roles in monitoring the spectrum. Here, we review the current literature on the molecular and immune mechanisms involving the transition from benign nevi to malignant melanoma. [ABSTRACT FROM AUTHOR]

Background: The incidence, histological subtypes, and tumor behaviors of cutaneous malignant melanoma are quite different in Asian and Western countries. Objectives: Our purpose was to define the epidemiology, tumor behaviors, and possible prognostic predictors of cutaneous melanomas based on an Eastern Taiwanese population. Methods: We conducted a retrospective study to collect cases of cutaneous melanoma at Buddhist Tzu-Chi General Hospital, Hualien, Taiwan, from May 1, 2003, to August 31, 2017. We analyzed mean age at onset, gender, primary tumor locations, histological subtypes, Breslow's thickness, Clark's level, ulceration, lymph nodes, and distant metastatic status. Univariate and multivariate analyses for survival were performed by means of Cox proportional hazard model. Survival curves were plotted by Kaplan–Meier method. Results: A total of 56 cases of cutaneous melanoma were recorded. The male-to-female ratio was 3.67:1. The median survival was 2.82 years (0.63–5.00 years). Acral melanoma (AM) accounts for 69.6% of cases, and feet are the most common location (62.5%). Acral lentiginous melanoma (ALM) is the most common histological type (44.6%), followed by nodular melanoma (33.9%). Poor prognostic factors include older age (≧65 years), male gender, Breslow's thickness >4 mm, distant metastasis, and head-and-neck location. Conclusion: AM is the most common location, and ALM is the most common histological type of cutaneous melanoma in Eastern Taiwan. Melanoma in Eastern Taiwan tends to be delay diagnosed with advanced stage and thicker tumors than Western Taiwan. Prudent palm and sole examinations, improved medical accessibility, and more public educational programs may help encourage the early detection of melanoma. [ABSTRACT FROM AUTHOR]

Acquired reactive perforating collagenosis (ARPC) is a rare condition caused by transepidermal elimination of collagen, elastin fibers and keratin. To date, the pathogenesis of ARPC remains unknown. Different hypotheses were proposed, including superficial microtrauma due to pruritus and subsequent scratching, diabetes-induced microangiopathy, epidermal and dermal abnormalities in metabolic disorders, dermal microdeposits in patients with chronic renal failure and vasculopathy underlying chronic venous insufficiency and hypertension. In the past two decades, oral allopurinol had been found to be effective in treating ARPC. We report a case of a 36-year-old pregnant woman with itchy skin lesions on the trunk and four limbs since 36 weeks of her gestation. Initially, she was prescribed with oral antihistamine and topical steroid but did not respond well. Skin biopsy was performed and was compatible with ARPC. Normal renal and liver function tests were noted, and the HLA-B5801 test was negative. We treated the patient with allopurinol. Significant improvement was noticed at 1-month follow-up. To the best of our knowledge, this is the first case successfully treating ARPC induced by pregnancy with allopurinol. On careful follow-up of laboratory data and HLA-B5801 test screening, allopurinol may be another effective treatment option for ARPC patients after pregnancy. [ABSTRACT FROM AUTHOR]