Follicular colonization in melanocytic nevi and melanoma: A literature review.

The lentiginous spread of melanocytes into the hair follicle can be observed in a number of benign melanocytic neoplasms such as in nevi but also in sun-induced melanocytic hyperplasia and melanoma. The follicular colonization by melanocytes in melanoma is classified into three distinct patterns: primary follicular melanoma, melanoma with folliculotropism, and invasive melanoma arising from melanoma in situ with folliculotropism. The role of follicular colonization in melanoma pathologic staging is still a matter of debate though the description of the latter has been recommended by the International Collaboration on Cancer Reporting. In this review, we will discuss the role of follicular colonization in melanoma and melanocytic nevi as well as the facts and controversies regarding this topic.

Mutational landscape in squamous cell carcinoma of the nail unit.

Squamous cell carcinoma (SCC) is the most common malignancy of the nail unit. Pathogenetic mechanisms are yet to be determined, and a deeper molecular characterization of this disease is still necessary. The aim was to obtain a molecular characterization of NU SCC samples using an NGS approach to identify the genetic drivers involved in this tumor. The presence of HPV infection was also assessed. Furthermore, the mutational status was correlated with specific clinical-pathological features for a better insight into the carcinogenesis of this uncommon tumor. We analysed twenty paraffin-embedded nail unit SCC samples from patients diagnosed with primary SCC of the nail unit by next genome sequencing. In the 20 tested samples, the neoplastic cells enrichment ranged from 10% to 50% (mean value: 25.7%). In 14/20 cases (70.0%), at least one mutation was detected; whereas in the other six cases (30.0%), no alterations were observed ('wild-type/WT cases'). Overall, a total of 23 mutations were identified in the 20 specimens. TP53 was the most mutated gene (6/20 cases, 30.0%), while cKit, GNAS, EGFR, DICER1 and CTNNB1 were observed in one sample each (5.0%). No clinical-pathological parameters (age, sex, depth of invasion-DOI, histological subtype, grading and HPV) were significantly associated with the mutational status. The nail unit SCC mutational landscape appeared to be heterogeneous, favouring the hypothesis of a complex pathogenesis and an interaction of multiple elements, including HPV infections. This wealth of information undoubtedly improves our understanding of SCC biology.

BRAF V600K vs. BRAF V600E: a comparison of clinical and dermoscopic characteristics and response to immunotherapies and targeted therapies.

BACKGROUND: A number of mutations related to malignant melanoma (MM) have been identified, and of the mutated genes, BRAF has been found to be altered in > 50% of cases. Most of these have been BRAF V600E mutations, whereas the incidence of BRAF V600K may vary from 10% to 30%. Little is known about the clinical prognostic correlations of BRAF V600K MMs. We evaluated the clinical and dermoscopic features, incidence, therapy response and outcomes in the medium to long term. AIM: To compare the clinical and dermoscopic characteristics, the response to systemic therapies and the prognosis among MMs with BRAF V600E and BRAF V600K mutations. METHODS: We retrieved the data of patients tested in our centre for MM from 2012 to 2015, including clinical features, dermoscopic pictures, clinical history and tumour mutations. Only patients with BRAF V600E and BRAF V600K mutations were included. Any MMs positive for BRAF V600K mutation were collected, and the number of V600K cases and their features were used to extract the same number of patients with BRAF V600E from our database using a matching method. The clinical and dermoscopic presentation, therapy response and disease progression of the two groups were then evaluated. RESULTS: In total, 132 cases of BRAF V600E-mutated MMs were identified, and then randomized with a propensity-score method to match the 10 retrieved cases of BRAF V600K mutation. Both groups had a nodular appearance to the tumours and an advanced disease stage, and no significant differences in dermoscopic features were highlighted. During the follow-up period, four patients with BRAF V600K died of disease-specific causes. Moreover, we found a higher frequency of metastasis, a faster disease progression and more rapid mortality in patients with BRAF V600K. CONCLUSION: Despite the small size of this study, the results show similar clinical and dermoscopic characteristics between V600E and V600K mutations, but compared with BRAF V600E MMs, BRAF V600K MMs seem to be less responsive to therapy and have a worse prognosis.

Cutaneous Melanomas: A Single Center Experience on the Usage of Immunohistochemistry Applied for the Diagnosis.

Cutaneous melanoma (cM) is the deadliest of all primary skin cancers. Its prognosis is strongly influenced by the stage at diagnosis, with early stages having a good prognosis and being potentially treatable with surgery alone; advanced stages display a much worse prognosis, with a high rate of recurrence and metastasis. For this reason, the accurate and early diagnosis of cM is crucial-misdiagnosis may have extremely dangerous consequences for the patient and drastically reduce their chances of survival. Although the histological exam remains the "gold standard" for the diagnosis of cM, a continuously increasing number of immunohistochemical markers that could help in diagnosis, prognostic characterization, and appropriate therapeutical choices are identified every day, with some of them becoming part of routine practice. This review aims to discuss and summarize all the data related to the immunohistochemical analyses that are potentially useful for the diagnosis of cM, thus rendering it easier to appropriately applicate to routine practice. We will discuss these topics, as well as the role of these molecules in the biology of cM and potential impact on diagnosis and treatment, integrating the literature data with the experience of our surgical pathology department.

Folliculotropism in head and neck lentigo maligna and lentigo maligna melanoma.

BACKGROUND: Lentigo maligna (LM) and lentigo maligna-melanoma (LMM) are histotypes of melanoma arising in skin with cumulative solar radiation damage. The extension of atypical melanocytes to the hair follicle (folliculotropism) is a histopathological feature of LM/LMM. Its role has not been totally clarified, but it may be correlated to treatment response in LM or to progression in LMM. OBJECTIVE: This retrospective, multicentric study aims to identify dermatoscopic features associated with folliculotropism in LMs/LMMs. PATIENTS AND METHODS: We analyzed cases of head and neck LMs/LMMs diagnosed between 2005-2014 at Melanoma Units, University of Bologna/Modena/Florence/Siena (Italy), Nice (France): 25 LMs and 73 LMMs were included. RESULTS: Grey circles (44 %) indicated an isthmic/bulb level of involvement, which were completely absent in the infundibular LM lesions (P = 0.041). In the group of LMMs, light/dark brown pseudonetwork and light brown structureless areas were an indicator of diffuse distribution of malignant melanocytes in the follicular units (P < 0.001 and P = 0.001, respectively), while grey circles indicated focal or diffuse distribution (P < 0.001). CONCLUSIONS: A better understanding of the extension of malignant melanocytes is helpful, aiding clinicians in their decision to perform a radical excision or obtaining a biopsy in the most invasive area of the lesion, which includes potential folliculotropism.

Next-generation sequencing revealing TP53 mutation as potential genetic driver in dermal deep-seated melanoma arising in giant congenital nevus in adult patients: A unique case report and review of the literature.

Melanoma in giant congenital nevus (M-GCN) is a rare and potentially lethal neoplasm. In children, M-GCN appears as a dermal/deep-seated melanoma (DDM-GCN) with histopathologic features difficult to distinguish from proliferative nodules (PNs-GCN). DDM-GCN in adults is an anecdotal entity and only 8 cases have been described and genetically characterized. We report the first case of DDM-GCN in a 34-year-old man characterized with a large-panel next-generation sequence (NGS) highlighting a TP53 mutation with a UV-signature (C>T substitution) in DDM but not in PNs-GCN and GCN. Curiously, DDM showed an aberrant p16 overexpression without detection of CDKN2A mutation at NGS. In line with previous studies, it supports a different pathway in children and adults: UV-induced mutations may be involved in the latter not only by CDKN2A but also by TP53 mutations, with a potentially confusing overexpression of p16 protein. While these data need to be confirmed in larger cases series, our results show that NGS could be an additional genetic diagnostic tool in DDM-GCN.

The role of topical imiquimod in melanoma cutaneous metastases: A critical review of the literature.

Despite of the emerging new systemic and local oncologic treatments (immunotherapy and checkpoint inhibitors, oncolytic viral treatments and injected immunostimulants) the management of skin melanoma metastasis can be still challenging. The main aim of this review was to assess the efficacy and the role of imiquimod in local metastatic melanoma disease. An extensive literature review was performed from September 2000 to March 2020 using PubMed, MEDLINE, Embase, and Cochrane Library databases. Selected articles regarded topical imiquimod, its mode of action as an antitumoral agent and its applications in melanoma metastases treatment. We analyzed a total of 18 published article of clinical cases and small case series and five studies: two retrospective large case series, two Phase I and II clinical trials and one cohort non randomized study. Generally, the treatment is safe and well tolerated. Imiquimod lead to an unstable locoregional control. The use of topical imiquimod for the treatment of MM cutaneous metastases should be considered in selected cases and in palliative settings.

It's time for Mohs: Micrographic surgery for the treatment of high-risk basal cell carcinomas of the head and neck regions.

Basal cell carcinoma (BCC) is the most common variety of non-melanoma skin cancer and its incidence is increasing worldwide. The centrofacial sites (area H) are considered a high-risk factor for BCC local recurrence. Mohs micrographic surgery (MMS) is a technique that allows intraoperative microscopic control of the surgical margins and is a good treatment option when tissue conservation is required for esthetic or functional reasons or for high-risk lesions. The present study aimed to evaluate the recurrence rate of head and neck high-risk BCCs comparing MMS vs conventional surgical excision. Clinical data of patients diagnosed from September 2014 to March 2017, referring to the Dermatology Unit of the Policlinico Sant'Orsola-Malpighi, University of Bologna, were retrospectively evaluated (285 treated with MMS and 378 treated with traditional surgery). Of the 285 patients treated with MMS, 9 experienced a recurrence (3.1%). Of the 378 patients treated with traditional surgery, 53 relapsed (14%), 13 of whom presented residual tumor on the deep or lateral margins of the main surgical specimen. Our study confirms the trend reported in the literature that MMS represents the best treatment option for high-risk BCCs arising in the head and neck region or presenting as a recurrence (P < .00001). Many more MMS centers and more trained dermatologists are needed worldwide in order to deal with the increasing number of BCC diagnosed every year.

Basal Cell Carcinoma: A Comprehensive Review.

Basal cell carcinoma (BCC) is the most common type of carcinoma worldwide. BCC development is the result of a complex interaction between environmental, phenotypic and genetic factors. However, despite the progress in the field, BCC biology and mechanisms of resistance against systemic treatments have been poorly investigated. The aim of the present review is to provide a revision of BCC histological and molecular features, including microRNA (miRNA) dysregulation, with a specific focus on the molecular basis of BCC systemic therapies. Papers from the last ten years regarding BCC genetic and phenotypic alterations, as well as the mechanism of resistance against hedgehog pathway inhibitors vismodegib and sonidegib were included. The involvement of miRNAs in BCC resistance to systemic therapies is emerging as a new field of knowledge.

Oral and nail pigmentations: a useful parallelism for the clinician.

Oral (OP) and nail (NP) pigmentations may occur simultaneously in physiological or pathological conditions, and may be a sign of underlying syndromic conditions that necessitate further investigation and treatment. Interestingly, the nail unit and oral cavity show a clinical parallelism that may help the clinician to conduct a correct examination and reach a prompt diagnosis. Both OP and NP can manifest clinically with focal or diffuse involvement and are due to external factors (exogenous pigmentation, drug-induced pigmentation) or endogenous factors (racial pigmentation, post-inflammatory pigmentation, nevi, genetic conditions and other disorders). The most concerning differential diagnosis is melanoma. Here we report the pathogenetic basis of OP and NP, together with the description of similar clinical features. To the best of our knowledge this is the first paper to summarize and describe the causes of pigmentation of both the oral cavity and the nail unit.

Diagnostic Efficacy of Digital Dermoscopy and Clinical Findings in Thin Melanoma of the Lower Limbs.

The introduction of dermoscopy has improved the accuracy of diagnosis of melanoma. However, early stage melanoma can be difficult to diagnose. Eighty-nine cases of thin melanoma with a Breslow thickness ≤1 mm located on the lower limb and diagnosed between 2008 and 2016 were assessed using 4 dermoscopic algorithms: (i) modified pattern analysis; (ii) ABCD rule of dermoscopy; (iii) 7-point checklist; and (iv) Menzies' method. Two groups of early stage melanomas of the legs were identified: "difficult to diagnose melanomas" (DDM) and "non-difficult to diagnose melanomas" (NDDM). In our series the dermoscopic features of DDM were difficult to differentiate from melanocytic naevi, and the reticular pattern was the most frequently observed. "Depigmentation" was the only specific criterion associated with DDM. The sensitivity of diagnostic systems for thin melanomas of the lower limbs was lower than in previous studies. This result could be related to the lower mean Breslow thickness of the invasive melanomas in our sample and the high number of melanomas in situ. In conclusion, early stage melanoma of the legs may be difficult to detect at clinical examination or with dermoscopic examination alone. Focusing on depigmentation in dermoscopy associated with anamnestic features could be a useful tool to detect difficult thin melanomas. In addition, sequential dermoscopy is recommended for high-risk patients with previous melanomas or atypical mole syndrome.

Halolike Phenomenon Around a Café au Lait Spot Superimposed on a Mongolian Spot.

An 8-month-old Caucasian infant with neurofibromatosis type 1 presented with a congenital plexiform neurofibroma and multiple café au lait spots. A pale area surrounded one of the café au lait spots located on the left gluteus in the area of dermal melanocytosis. This halolike phenomenon results from the disappearance of the Mongolian spot around the café au lait spots, revealing normal pigmented skin. This sign has been described rarely in the literature and the pathogenic mechanism is unclear.

Lane's Disease (Erythema Palmare Hereditarium): A Report of Five Cases and a Review of the Literature.

BACKGROUND: Erythema palmare hereditarium (EPH), also known as Lane's disease, is a rare, benign condition presenting as persistent erythema involving the palms. EPH can appear at birth or later in life and usually in at least two members of the same family, although a sporadic case has been reported. METHODS: We report five cases of EPH and offer a review of the current literature. The first and second cases are twin boys presenting with erythema mainly on the thenar and hypothenar eminences and on the phalanges that appeared 8 months after birth. The third case is a girl with congenital palmar erythema and two other capillary malformations. The fourth case is a 58-year-old woman with palmar erythema that appeared after pregnancy. Her 32-year-old daughter had presented with the same palm redness since birth. RESULTS: A review of the literature shows that women are affected almost three times more than men. Dermoscopic evaluation showed red structureless areas with arborizing vessels, mainly running parallel along follicular openings. CONCLUSION: EPH should be considered in all patients presenting with palmar erythema, especially in familial long-lasting forms. It can be congenital or acquired, but the pathogenetic mechanism is unclear. To the best of our knowledge, this is the first dermatoscopic study of EPH and the largest case series reported in the literature, involving two families and one sporadic case.