Melanoma on chronically sun-damaged skin: Lentigo maligna and desmoplastic melanoma

Perineuriomatous Melanocytic Nevi: A Case Series of Four Cases

BACKGROUND

Melanocytic tumors with perineuriomatous differentiation may pose diagnostic challenges. This study explores characteristics of perineuriomatous melanocytic nevi, an entity merging features of perineurioma and melanocytic nevi. The aim is to elucidate histopathological features of perineuriomatous nevi to allow dermatopathologists to recognize them and differentiate them from other spindle cell lesions.

METHOD

This study reviews four cases (2020-2023) of melanocytic nevi with perineuriomatous components.

RESULTS

All cases comprised adults (median age: 64.50, mean age: 60.25), with a female predominance, and exhibited clinical features characterized by irregular brown macules or papules on the trunk and extremities. Histopathologically, all lesions were compound, and biphasic patterns were evident, encompassing superficial nevoid and deeper spindled populations arranged in whorled fascicles and embedded in a sclerotic or myxoid stroma. Immunohistochemistry revealed expression of at least one perineuriomatous marker in deeper cells. Cases were assessed and compared with previously published cases for comprehensive insights. Three of our four cases demonstrated the presence of a junctional component that was smaller than the dermal component. We suggest that this unusual feature, which we term the "reverse shoulder", may allow dermatopathologists to help consider perineurial differentiation in the appropriate setting.

CONCLUSION

Perineuriomatous nevi can pose diagnostic challenges. This study contributes to the growing body of literature on perineuriomatous nevi, emphasizing their unique features and the importance of accurate diagnosis to avoid unnecessary interventions.

Amelanotic Melanoma-Biochemical and Molecular Induction Pathways

Amelanotic melanoma (AM) is a subtype of hypomelanotic or completely amelanotic melanoma. AM is a rare subtype of melanoma that exhibits a higher recurrence rate and aggressiveness as well as worse surveillance than typical melanoma. AM shows a dysregulation of melanin production, cell cycle control, and apoptosis pathways. Knowing these pathways has an application in medicine due to targeted therapies based on the inhibiting elements of the abovementioned pathways. Therefore, we summarized and discussed AM biochemical and molecular induction pathways and personalized medicine approaches, clinical management, and future directions due to the fact that AM is relatively rare. AM is commonly misdiagnosed. Hence, the role of biomarkers is becoming significant. Nonetheless, there is a shortage of biomarkers specific to AM. BRAF, NRAS, and c-KIT genes are the main targets of therapy. However, the role of BRAF and KIT in AM varied among studies. BRAF inhibitors combined with MAK inhibitors demonstrate better results. Immune checkpoint inhibitors targeting CTLA-4 combined with a programmed death receptor 1 (PD-1) show better outcomes than separately. Fecal microbiota transplantation may overcome resistance to immune checkpoint therapy of AM. Immune-modulatory vaccines against indoleamine 2,3-dioxygenase (IDO) and PD ligand (PD-L1) combined with nivolumab may be efficient in melanoma treatment.

Desmoplastic melanoma

Desmoplastic melanoma is a rare fibrosing variant of melanoma. It typically affects elderly patients but can occasionally affect young or middle-aged individuals. Desmoplastic melanoma is relevant as a diagnostic pitfall for pure tumor variants' distinct histopathologic and clinical features. The latter includes a lower regional lymph node involvement frequency and a more favorable prognosis among thick melanomas. Classic cases of desmoplastic melanoma tend to carry a high mutation burden. Patients with metastases from those tumors tend to respond favorably to novel immunotherapies.

Lentigo maligna: a comprehensive review on diagnosis and treatment

Lentigo maligna (LM), a form of melanoma in situ, and LM melanoma (LMM), its invasive counterpart, exhibit distinctive epidemiology, risk factors, and clinical features compared to other melanoma subtypes. Notably, LM occurs on chronically sun-damaged skin presenting as a slow-growing, ill-defined patch which makes it difficult to diagnose and to treat. Additionally, while LM generally presents a favourable prognosis, it can also lead to dermal invasion and behave similarly to other melanomas with the same Breslow thickness. Hence, surgery continues to be the cornerstone treatment. Wide excisions are often necessary, but challenges arise when these lesions manifest in cosmetically sensitive regions, limiting the feasibility and desirability of large excisions. Specialized approaches, including margin-controlled surgery and image-guided treatment with reflectance confocal microscopy, have been developed to address these issues. Other non-surgical treatments such as cryosurgery, imiquimod, radiotherapy, or photodynamic therapy, may also be used but commonly present with recurrent/persistent disease. Herein we comprehensively review the existing literature on the management of LM/LMM, and discus the potential new advances on managing this challenging skin cancer.

Clinical Characteristics and Special Considerations in the Management of Rare Melanoma Subtypes

Rare histologic subtypes of melanoma, including acral, mucosal, uveal, and desmoplastic melanomas, only make up 5% of all diagnosed melanomas and are often underrepresented in large, randomized trials. Recent advancements in systemic therapy have shown marked improvement in pathologic response rates, improving progression-free and overall survival among cutaneous melanoma patients, but there are limited data to demonstrate improved survival among rarer subtypes of melanoma. Acral melanoma has a poor response to immunotherapy and is associated with worse survival. Mucosal melanoma has a large variability in its presentation, a poor prognosis, and a low mutational burden. Uveal melanoma is associated with a high rate of liver metastasis; recent adoption of infusion and perfusion therapies has demonstrated improved survival among these patients. Desmoplastic melanoma, a high-risk cutaneous melanoma, is associated with high locoregional recurrence rates and mutational burden, suggesting this melanoma may have enhanced response to immunotherapy. While these variants of melanoma represent distinct disease entities, this review highlights the clinicopathologic characteristics and treatment recommendations for each of these rare melanomas and highlights the utility of modern therapies for each of them.

Joinpoint regression analysis of recent trends in desmoplastic malignant melanoma incidence and mortality: 15-year multicentre retrospective study

BACKGROUND

Recent data reveal a marked rise in the detection and mortality rates of Desmoplastic Malignant Melanoma (DMM). This trend underscores the imperative for an in-depth analysis of DMM's epidemiology, which is crucial for the formulation of precise medical and public health strategies. This investigation seeks to elucidate the variations in the incidence and mortality of DMM over a 15-year period (2005-2019).

METHODS

Data on DMM patients was sourced from the Surveillance, Epidemiology, and End Results (SEER) database. Both incidence and incidence-based mortality rates (IBM) were directly extracted from the SEER database. Joinpoint regression was used to analyze and calculate the average annual percent change (AAPC) and its 95% confidence interval (CI).

RESULTS

Between 2005 and 2019, 3,384 DMM cases were identified, boasting an age-adjusted incidence rate of 36.3 cases per 1000,000 person-years (95% CI 3.51-3.76) and an IBM of 1.65cases per 1000,000 person-years (95% CI 1.57-1.74). Of these, 2,353 were males (69.53%) and 1,031 were females (30.47%). There were 1894 patients (55.97%) who were over 70 years old. Predominantly, DMM lesions manifested in exposed areas: Limbs (955, 28.22%), Face (906, 26.77%), and Scalp and Neck (865, 25.56%). The incidence of DMM increased significantly at a rate of APC = 0.9% during 2005-2019, while the incidence-based mortality showed a significant upward trend (APC = 7%) during 2005-2012, and slowly increasing trend (APC = 0.6%) during 2012-2019. In contrast to the modest upward trajectory in female incidence and mortality, male incidence initially surged, later declining, while male mortality peaked and stabilized post-2012. The primary sites for incidence and mortality were chronically sun-exposed areas: Face, Scalp and Neck, and Limbs.

CONCLUSIONS

In recent years, the incidence and incidence-based mortality of DMM have significantly increased. Each subgroup analysis has different trends, and these trends can provide better support for our exploration of DMM.

Interdisciplinary management of skin cancer

The interdisciplinary treatment of skin cancer in the head and neck area requires close collaboration between different specialist disciplines. The most common non-melanoma skin cancer tumor entities are cutaneous squamous cell carcinoma and basal cell carcinoma as well as their precursor lesions. One of the less common tumors is Merkel cell carcinoma, which also occurs primarily in light-exposed areas and, in contrast to squamous and basal cell carcinoma, is more likely to metastasize. Due to the low tendency of basal cell carcinoma as well as cutaneous squamous cell carcinoma to metastasize, a cure can often be achieved by surgery. If the tumor growth exceeds certain levels it may require collaboration between dermatology and otorhinolaryngology. The primary goal of this interdisciplinary collaboration is to achieve a functional, cosmetically and aesthetically acceptable result in addition to adequate tumor treatment. Depending on the stage of the tumor and the clinical course, a case may be discussed in an interdisciplinary tumor board in order to determine a personalised, appropriate and adequate treatment concept for each patient, including prevention, therapy and follow-up.

Lentigo Maligna Treatment-An Update

Lentigo maligna (LM) is a melanoma in situ that is prevalent in chronically sun-damaged skin. Characterized by a slow growth pattern and high mutation rates due to chronic UV exposure, LM poses diagnostic and therapeutic challenges, particularly given its tendency to mimic other skin lesions and its occurrence in cosmetically sensitive areas. Its diagnosis is based on an integrated approach using dermoscopy and reflectance confocal microscopy (RCM). Despite its slow progression, LM can evolve into lentigo maligna melanoma (LMM), making its treatment necessary. Treatment modalities encompass both surgical and non-surgical methods. Surgical treatments like Wide Local Excision (WLE) and Mohs Micrographic Surgery (MMS) aim for clear histological margins. WLE, a standard melanoma surgery, faces challenges from LM's subclinical extensions, which increase the recurrence risk. MMS, effective for large or poorly defined lesions, is defined by precise margin control while considering cosmetic outcomes. Non-surgical options, including radiotherapy and imiquimod, are alternatives for non-surgical candidates. Radiotherapy has been effective since the 1950s, offering good control and cosmetic results, especially for older patients. Imiquimod, an immunomodulator, shows promise in treating LM, though its application remains off-label. The increasing incidence of LM/LMM necessitates a balance in treatment choices to minimize recurrence and maintain cosmetic integrity. A multidisciplinary approach, integrating clinical examination with dermoscopy and RCM and histological assessment, is essential for accurate diagnosis and effective LM management.

The Keratinocyte in the Picture Cutaneous Melanoma Microenvironment

Melanoma progression is a multistep evolution from a common melanocytic nevus through a radial superficial growth phase, the invasive vertical growth phase finally leading to metastatic dissemination into distant organs. Melanoma aggressiveness largely depends on the propensity to metastasize, which means the capacity to escape from the physiological microenvironment since tissue damage due to primary melanoma lesions is generally modest. Physiologically, epidermal melanocytes are attached to the basement membrane, and their adhesion/migration is under the control of surrounding keratinocytes. Thus, the epidermal compartment represents the first microenvironment responsible for melanoma spread. This complex process involves cell-cell contact and a broad range of secreted bioactive molecules. Invasion, or at the beginning of the microinvasion, implies the breakdown of the dermo-epidermal basement membrane followed by the migration of neoplastic melanocytic cells in the superficial papillary dermis. Correspondingly, several experimental evidences documented the structural and functional rearrangement of the entire tissue surrounding neoplasm that in some way reflects the atypia of tumor cells. Lastly, the microenvironment must support the proliferation and survival of melanocytes outside the normal epidermal-melanin units. This task presumably is mostly delegated to fibroblasts and ultimately to the self-autonomous capacity of melanoma cells. This review will discuss remodeling that occurs in the epidermis during melanoma formation as well as skin changes that occur independently of melanocytic hyperproliferation having possible pro-tumoral features.

Lentigo maligna and lentigo maligna melanoma in vivo differentiation with dermoscopy and reflectance confocal microscopy: A retrospective, multicentre study

INTRODUCTION

Dermoscopic predictors of lentigo maligna (LM) and lentigo maligna melanoma (LMM) have been recently reported, but these have not been reported in reflectance confocal microscopy (RCM).

OBJECTIVES

(i) To validate dermoscopic predictors for LM/LMM, (ii) to identify RCM patterns in LM and LMM, and (iii) correlations between dermoscopic and RCM features in LM and LMM.

MATERIALS AND METHODS

A retrospective, multicentre study of consecutive lesions with histologically proven LM or LMM subtypes of the head and face, with complete sets of dermoscopic and RCM images.

RESULTS

A total of 180 lesions were included (n = 40 LMM). Previously reported differential dermoscopic features for LM subtypes were confirmed. Other features significantly associated with LMM diagnosis included irregular hyperpigmented areas, shiny white streaks, atypical vessels and light brown colour at dermoscopy and medusa head-like structures, dermal nests and nucleated cells within the papillae at RCM (p < 0.05). Correlations among LM lesions between dermoscopic and RCM features included brown to-grey dots and atypical cells (epidermis), grey colour and inflammation and obliterated follicles and medusa head-like structures. Among LMM lesions, significant correlations included obliterated follicles with folliculotropism, both irregular hyperpigmented areas and irregular blotches with widespread atypical cell distribution (epidermis), dermal nests and nucleated cells within the papillae (dermis). Irregular blotches were also associated with medusa head-like structures (dermal epidermal junction [DEJ]).

CONCLUSIONS

Dermoscopic and RCM features can assist in the in vivo identification of LM and LMM and many are correlated. RCM three-dimensional analysis of skin layers allows the identification of invasive components in the DEJ and dermis.

The limited value of sentinel lymph node biopsy in lentigo maligna melanoma: A nomogram based on the results of 29 years of the nationwide dutch pathology registry (PALGA)

BACKGROUND

Lentigo maligna melanoma (LMM) predominantly presents in the head and neck of the elderly. The value of sentinel lymph node biopsy (SLNB) for LMM patients remains to be determined, as the reported average yield of positive lymph nodes is less than 10%. In this nationwide cohort study, we wanted to identify LMM patients with an increased risk of SLNB-positivity.

METHODS

LMM with an SLNB indication according to the 8th AJCC melanoma guidelines were retrospectively identified from the nationwide network and registry of histo- and cytopathology in the Netherlands (PALGA). A penalized (LASSO) logistic regression analysis was performed to determine the optimal combination of clinicopathological factors to predict a positive SLNB.

RESULTS

Between 1991 and 2020, 1989 LMM patients met our inclusion criteria. SLNB was performed in 16.7% (n = 333) and was positive in 7.5% (25/333). The false-negative rate was 21.9%. Clinically detectable regional lymph node (LN) metastases were found in 1.3% (n = 25). Clinicopathological characteristics best predictive for SLNB-positivity (Odds ratio; 95% CI) were age (0.95; 0.91-0.99), ulceration 1.59 (0.44-4.83), T4-stage (1.81; 0.43-6.2), male sex (1.97; 0.79-5.27), (lymph)angioinvasion (5.07; 0.94-23.31), and microsatellites (7.23; 1.56-32.7) (C-statistic 0.75). During follow-up, regional LN recurrences were detected in 4.2% (83/1989) of patients, of which the majority (74/83) had no evidence of regional LN metastases at baseline.

CONCLUSION

Our findings confirm the limited SLNB-positivity in LMM patients. Based on the identified high-risk clinicopathological features, a nomogram was developed to predict the risk of a positive SLNB.

A risk-scoring model for the differential diagnosis of lentigo maligna and other atypical pigmented facial lesions of the face: The facial iDScore

BACKGROUND

Due to progressive ageing of the population, the incidence of facial lentigo maligna (LM) of the face is increasing. Many benign simulators of LM and LMM, known as atypical pigmented facial lesions (aPFLs-pigmented actinic keratosis, solar lentigo, seborrheic keratosis, seborrheic-lichenoid keratosis, atypical nevus) may be found on photodamaged skin. This generates many diagnostic issues and increases the number of biopsies, with a subsequent impact on aesthetic outcome and health insurance costs.

OBJECTIVES

Our aim was to develop a risk-scoring classifier-based algorithm to estimate the probability of an aPFL being malignant. A second aim was to compare its diagnostic accuracy with that of dermoscopists so as to define the advantages of using the model in patient management.

MATERIALS AND METHODS

A total of 154 dermatologists analysed 1111 aPFLs and their management in a teledermatology setting: They performed pattern analysis, gave an intuitive clinical diagnosis and proposed lesion management options (follow-up/reflectance confocal microscopy/biopsy). Each case was composed of a dermoscopic and/or clinical picture plus metadata (histology, age, sex, location, diameter). The risk-scoring classifier was developed and tested on this dataset and then validated on 86 additional aPFLs.

RESULTS

The facial Integrated Dermoscopic Score (iDScore) model consisted of seven dermoscopic variables and three objective parameters (diameter ≥ 8 mm, age ≥ 70 years, male sex); the score ranged from 0 to 16. In the testing set, the facial iDScore-aided diagnosis was more accurate (AUC = 0.79 [IC 95% 0.757-0.843]) than the intuitive diagnosis proposed by dermatologists (average of 43.5%). In the management study, the score model reduced the number of benign lesions sent for biopsies by 41.5% and increased the number of LM/LMM cases sent for reflectance confocal microscopy or biopsy instead of follow-up by 66%.

CONCLUSIONS

The facial iDScore can be proposed as a feasible tool for managing patients with aPFLs.

Piezo1 in skin wound healing and related diseases: Mechanotransduction and therapeutic implications

Skin wound healing is a multifaceted and intricate process involving inflammation, tissue proliferation, and scar formation, all of which are accompanied by the continuous application of mechanical forces. Mechanotransduction is the mechanism by which the skin receives and reacts to physical signals from the internal and external environment, converting them into intracellular biochemical signals. This intricate process relies on specialized proteins known as mechanotransducers, with Piezo1 being a critical mechanosensitive ion channel that plays a central role in this process. This article provides an overview of the structural characteristics of Piezo1 and summarizes its effects on corresponding cells or tissues at different stages of skin trauma, including how it regulates skin sensation and skin-related diseases. The aim is to reveal the potential diagnostic and therapeutic value of Piezo1 in skin trauma and skin-related diseases. Piezo1 has been reported to be a vital mediator of mechanosensation and transduction in various organs and tissues. Given its high expression in the skin, Piezo1, as a significant cell membrane ion channel, is essential in activating intracellular signaling cascades that trigger several cellular physiological functions, including cell migration and muscle contraction. These functions contribute to the regulation and improvement of wound healing.

Development and Implementation of a Web-Based International Registry Dedicated to Atypical Pigmented Skin Lesions of the Face: Teledermatologic Investigation on Epidemiology and Risk Factors

Background: Atypical pigmented facial lesions (aPFLs) often display clinical and dermoscopic equivocal and/or overlapping features, thus causing a challenging and delayed diagnosis and/or inappropriate excisions. No specific registry dedicated to aPFL paired with clinical data is available to date. Methods: The dataset is hosted on a specifically designed web platform. Each complete case was composed of the following data: (1) one dermoscopic picture; (2) one clinical picture; (3) two lesion data, that is, maximum diameter and facial location (e.g., orbital area/forehead/nose/cheek/chin/mouth); (4) patient's demographics: family history of melanoma, history of sunburns in childhood, phototype, pheomelanine, eyes/hair color, multiple nevi/dysplastic nevi on the body; and (5) acquisition device (videodermatoscope/camera-based/smartphone-based system). Results: A total of 11 dermatologic centers contributed to a final teledermoscopy database of 1,197 aPFL with a distribution of 353 lentigo maligna (LM), 146 lentigo maligna melanoma (LMM), 231 pigmented actinic keratoses, 266 solar lentigo, 125 atypical nevi, 48 seborrheic keratosis, and 28 seborrheic-lichenoid keratoses. The cheek site was involved in half of aPFL cases (50%). Compared with those with the other aPFL cases, patients with LM/LMM were predominantly men, older (69.32 ± 12.9 years on average vs. 62.69 ± 14.51), exhibited larger lesions (11.88 ± 7.74 mm average maximum diameter vs. 9.33 ± 6.46 mm), and reported a positive history of sunburn in childhood. Conclusions: The iDScore facial dataset currently represents a precious source of data suitable for the design of diagnostic support tools based on risk scoring classifiers to help dermatologists in recognizing LM/LMM among challenging aPFL in clinical practice.

Clinical, Dermoscopic, and Histological Characteristics of Melanoma Patients According to the Age Groups: A Retrospective Observational Study

BACKGROUND

Although the role of melanoma risk factors is well documented, their correlation with patients' age is less frequently analyzed.

METHOD

The analysis was performed among 189 melanoma patients in different age groups, including <30 years, 31-60 years, and >60 years, to investigate the risk factors, topography, and coexistence of morphological features of 209 melanomas (dermoscopic and histopathological).

RESULTS

Among the youngest age group, no correlation with the presence of estimated risk factors was found. The most common dermoscopic pattern was spitzoid and multicomponent asymmetric. The group of middle-aged patients was the most diverse in terms of the occurrence of risk factors, solar lentiginosis, dermoscopic patterns, topography, histological subtypes, and invasiveness of melanomas. The oldest group characterized a strong correlation between solar lentiginosis, NMSC comorbidity, the prevalence of facial melanomas, the dermoscopic pattern of melanoma arising on chronic sun-damaged skin, and regression.

CONCLUSION

The findings regarding the presence of age-specific features in melanoma patients, especially in the youngest and middle-aged groups, might be helpful for clinicians and to target secondary prevention efforts.

Local Recurrence Rates After Excision of Desmoplastic Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Few prospective studies have evaluated local recurrence rates (LRR) after excision of desmoplastic melanoma (DM); however, several retrospective studies have reported high LRR.

OBJECTIVE

To determine LRR after excision of DM and evaluate factors affecting LRR.

MATERIALS AND METHODS

Systematic review of the PubMed, Embase, and Web of Science databases was performed to identify studies reporting local recurrence after excision of DM with conventional wide local excision (WLE), Mohs micrographic surgery (MMS), or staged excision (SE). Meta-analysis was performed to calculate summary LRR and pooled risk ratios (RR).

RESULTS

Literature search identified 4 studies evaluating MMS or SE (total n = 61 DM). 53 studies assessed WLE ( n = 3,080) and were analyzed quantitatively. The overall LRR after WLE of DM was 21% (95% CI, 0.16-0.28; n = 2,308). Local recurrence rate was higher with positive/unknown histologic excision margins (49%, 95% CI, 0.25-0.74; n = 91) versus negative histologic margins (11%, 95% CI, 0.07-0.17; n = 1,075; [ p < .01]). Neurotropism was also associated with increased LRR (RR, 1.79; 95% CI, 1.34-2.38, p < .01; n = 644).

CONCLUSION

DM has high LRR after WLE. Local recurrence risk was greatest with positive excision margins, indicating the importance of achieving negative microscopic margins. Greater study of MMS and SE for DM is required.

Concordance of reflectance confocal microscopy and gene expression profiling for melanocytic lesions with uncertain malignant potential: A case series

For a small yet significant proportion of melanocytic lesions, histopathologic analysis may be unable to definitively evaluate malignant potential. These cases may signify a specific need for newer ancillary diagnostic technologies, including in vivo reflectance confocal microscopy (RCM) and gene expression profiling (GEP), both of which are highly sensitive in the diagnosis of melanoma. We report four cases of clinically suspicious melanocytic lesions that lacked definitive malignant features on histopathology and that were aided by use of RCM and GEP. Three of the four cases showed concordance between RCM and GEP in the diagnosis of melanoma. In one case, RCM was suggestive of melanoma; on the other hand, GEP and histopathology supported a final diagnosis of compound Spitz nevus. These cases support the role of RCM as a novel, non-invasive diagnostic tool to aid in the diagnosis of clinically suspicious melanocytic lesions with uncertain malignant potential, although RCM may have relatively lower accuracy for some atypical spitzoid lesions.

The Complex Interplay between Nevi and Melanoma: Risk Factors and Precursors

One effort to combat the rising incidence of malignant melanoma is focused on early detection by the clinical and dermoscopic screening of melanocytic nevi. However, the interaction between nevi, which are congenital or acquired benign melanocytic proliferations, and melanoma is still enigmatic. On the one hand, the majority of melanomas are thought to form de novo, as only a third of primary melanomas are associated with a histologically identifiable nevus precursor. On the other hand, an increased number of melanocytic nevi is a strong risk factor for developing melanoma, including melanomas that do not derive from nevi. The formation of nevi is modulated by diverse factors, including pigmentation, genetic risk factors, and environmental sun exposure. While the molecular alterations that occur during the progression of a nevus to melanoma have been well characterized, many unanswered questions remain surrounding the process of nevus to melanoma evolution. In this review, we discuss clinical, histological, molecular, and genetic factors that influence nevus formation and progression to melanoma.

Partially Dedifferentiated Primitive Malignant Melanoma with Pseudo-Angiomatous Features: A Case Report with Review of the Literature

Malignant melanoma (MM) is traditionally known as the "great mime" of human pathology, as it is potentially capable of imitating the most disparate neoplasms. It is known that in addition to the more classic histotypes of MM, there are also rare forms, including angiomatoid MM. Similarly, it has been amply demonstrated in the literature that MM is capable of dedifferentiating, losing melanocytic lineage markers, constituting a diagnostic challenge for the pathologist. Although 5 cases of primary angiomatoid MM have been described in the literature, to the best of our knowledge, no cases of dedifferentiated melanoma with pseudo-angiomatoid aspects have ever been described. In this paper, we present a very rare case of partially dedifferentiated MM in which the most dedifferentiated component lost melanocytic lineage immunohistochemical markers and assumed a pseudo-angiomatous morphology. Given the rarity of the case, we carried out a literature review of similar cases described, trying to draw new future perspectives not only about this particular variant of MM but also about the widest field of dedifferentiation/undifferentiation of MM.

A cohort analysis of surgically treated primary head and neck lentigo maligna (melanoma): Prognostic value of melanoma subtype and new insights in the clinical value of guideline adherence

BACKGROUND

Knowledge about lentigo maligna (melanoma) (LM/LMM) and its associated prognostic clinicopathological characteristics are limited compared to that of non-LM/LMM subtypes. The current study aimed to determine the clinical relevance of the LM/LMM subtype and its influence on recurrence and survival outcomes.

METHODS

All consecutive cases of primary cutaneous head and neck LM/LMM treated by wide local excision over a ten-year period were retrospectively reviewed and compared to non-LM/LMM. Clinical outcome and prognostic factors were assessed by cumulative incidence and competing risk analyses.

RESULTS

A total of 345 patients were identified. Specific clinicopathological characteristics such as lower median Breslow thickness (1.6 mm versus 2.1 mm; P = 0.013), association with diagnostic sampling errors (17.3% versus 5.2%; P = 0.01), and increased risk of local recurrences due to incomplete resection (18.7% versus 2.3%; P < 0.001), were significantly associated with LM/LMM. Guideline adherence was similar between the two study groups. The positive nodal status at baseline for LMM was low compared to non-LM/LMM (4.2% vs 17.9%; P = 0.037). The LMM subtype, facial localization, and reduced surgical margins (i.e., guideline non-adherence) were not shown to be independent prognostic factors for disease-free, melanoma-specific, or overall survival after correction for competing risks such as patient age and Breslow thickness.

CONCLUSIONS

The LMM subtype was not shown to be prognostically different from non-LM/LMM when corrected for other variables of influence such as patient age and Breslow thickness. Reduced resection margins did not seem to affect disease-free, and melanoma-specific survival and warrant LM/LMM-specific guidelines. Further research is needed to evaluate the value of SLNB in LMM patients.

The Interplay between Tumour Microenvironment Components in Malignant Melanoma

Malignant melanoma has shown an increasing incidence during the last two decades, exhibiting a large spectrum of locations and clinicopathological characteristics. Although current histopathological, biochemical, immunohistochemical, and molecular methods provide a deep insight into its biological behaviour and outcome, melanoma is still an unpredictable disease, with poor outcome. This review of the literature is aimed at updating the knowledge regarding melanoma’s clinicopathological and molecular hallmarks, including its heterogeneity and plasticity, involving cancer stem cells population. A special focus is given on the interplay between different cellular components and their secretion products in melanoma, considering its contribution to tumour progression, invasion, metastasis, recurrences, and resistance to classical therapy. Furthermore, the influences of the specific tumour microenvironment or “inflammasome”, its association with adipose tissue products, including the release of “extracellular vesicles”, and distinct microbiota are currently studied, considering their influences on diagnosis and prognosis. An insight into melanoma’s particular features may reveal new molecular pathways which may be exploited in order to develop innovative therapeutic approaches or tailored therapy.

Cutaneous melanoma survival rates of the elderly are not worse than those of the young, yet they have some specific differences

Introduction

The incidence of cutaneous melanoma among the elderly has increased significantly. Unfavorable survival rates are associated with insufficient patient managements and poor prognostic features in the elderly. We aimed to compare elderly (≥75 years) and younger (<75 years) patients with cutaneous melanoma to determine the differences and the prognostic significance of age.

Materials and Methods

The retrospective data of 117 elderly and 232 younger patients with cutaneous melanoma were compared.

Results

The median age of the elderly patients was 78 years (75-104), and 51.3% of the patients were female. Of the patients, 14.5% were in the metastatic stages. Clinicopathologic factors such as extremity melanomas (P = 0.01), Clark levels IV-V (P = 0.04), ulceration (P = 0.009), and neurotropism (P = 0.03) were significantly more common in elderly patients. However, BRAF mutation was significantly more common in younger patients (P = 0.003). Overall survival (OS) and recurrence-free survival (RFS) rates of both the groups were similar. Lymph node involvement (P < 0.005), distant metastasis (P < 0.005), and relapse of disease (P = 0.02) were associated with poor OS in elderly patients. Tumor-infiltrating lymphocytes was associated with prolonged RFS (P = 0.05), while extremity melanomas (P = 0.01), lymphovascular invasion (P = 0.006), and lymph node involvement (P < 0.005) had negative impact on RFS.

Conclusions

Although elderly patients with cutaneous melanoma had different clinicopathologic features in our series, their survival rates are similar to those of younger patients, which shows that age alone is inadequate to determine the prognosis. Disease stage and a comprehensive geriatric assessment might assist to determine appropriate management.

Vitamin D: Skin, sunshine, and beyond

Vitamin D is a steroid hormone of importance to the field of dermatology. Skin is unique in that it is the site of vitamin D synthesis upon sun exposure and a target organ for its activity. We explore the physiology and metabolic mechanism of action of vitamin D, as well as its effects on the skin. We also discuss the current evidence of the efficacy and safety of oral and topical vitamin D analogues on skin conditions such as psoriasis, atopic dermatitis, vitiligo, sunburn, actinic keratosis, and fibrosing skin disorders. Based on currently available scientific evidence, the National Academy of Medicine's recommended dietary allowance for vitamin D ranges from 400 IU to 800 IU daily based on age categories.

Complex melanoma of the scalp: Diagnosis and management aided by confocal microscopy

Melanomas of lentigo maligna subtype are a steadily growing problem and frequently represent a clinical challenge. A case is reported of a complex melanoma of the scalp illustrating the critical role of confocal microscopy for optimal diagnosis and management.

c-Kit inhibitors for unresectable or metastatic mucosal, acral or chronically sun-damaged melanoma: a systematic review and one-arm meta-analysis

BACKGROUND

Activating genomic alterations of the receptor tyrosine kinase KIT are found preferentially in certain melanoma subtypes such as acral and mucosal melanoma or melanoma arising in chronically sun-damaged skin. However, the therapeutic value of c-Kit inhibitors for these subtypes currently remains unclear.

OBJECTIVES

The objective of this study was to summarise the efficacy and safety of c-Kit inhibitors for unresectable or metastatic mucosal, acral or chronically sun-damaged melanoma.

METHODS

We performed a systematic literature research in MEDLINE, Embase and CENTRAL and hand searched pertinent trial registers and conference abstracts for eligible trials until 23rd June 2020. Results were pooled using a random-effects model to calculate pooled proportions of objective response rates (ORRs) and severe adverse events (sAEs) from unselected KIT mutant or amplified cohorts.

RESULTS

Nineteen single-arm studies with an overall sample size of 601 patients were included. The studies investigated imatinib (n = 8), nilotinib (n = 7), dasatinib (n = 3) and sunitinib (n = 1). The pooled ORR for all inhibitors was 15% (95% confidence interval [CI]: 12-18%). Subgroup analysis revealed the highest ORR (20%; 95% CI: 14-26%) for nilotinib. The ORR for mucosal melanoma was 14% (95% CI: 6-24%) and 22% for acral lentiginous melanoma (95% CI: 14-30%). At least one sAE was reported in 42% of patients (95% CI: 34-50%).

CONCLUSIONS

c-Kit inhibitors represent a valuable treatment option for patients with KIT-mutant melanoma, in particular for mutations of exons 11 and 13. Furthermore, high-quality trials are urgently needed to investigate putative combinations of specific targeted therapies with immunotherapy.

Lentigo Maligna

Lentigo maligna (LM) is a melanocytic neoplasm found on chronically sun-exposed areas of the body, particularly the head and neck. It commonly occurs in the elderly and has been referred to as a "senile freckle." It has also been termed "Hutchinson melanotic freckle," as it was first described by John Hutchinson in 1892. LM is defined as melanoma in situ and thus confined to the epidermis. LM lesions that invade the dermis are termed lentigo maligna melanoma, 1 of the 4 subtypes of malignant melanoma.

Desmoplastic Melanoma: A Clinicopathological Analysis of Three Cases in the Chinese Population

Purpose

To investigate the clinicopathological characteristics and immunophenotype of desmoplastic melanoma (DM) in the Chinese population.

Patients and Methods

We report three cases of DM diagnosed by the Pathology Department of Shanghai Dermatology Hospital. We describe the clinical and pathological characteristics of the three cases and examine molecular markers used in the diagnosis of DM. Finally, we summarize the current literature in the DM field.

Results

Clinically, lesions in the three DM patients were characterized by non-pigmented nodules or papules. Microscopically, we observed an abundance of fibrous interstitium mixed with spindle cells exhibiting various degrees of atypia. Occasionally, these structures exhibited changes in lentigo maligna at the epidermal junction, accompanied by the presence of lymphoid follicular structures and neurophilic behavior. Diagnosis of DM was confirmed by immunohistochemical staining, which revealed high expression levels of S-100 and SOX-10. Melanocyte markers were focally positive or negative. Unlike DMs from other populations, our three patients were negative for WT-1 and P53. All three cases received surgical resection, which is the preferred treatment for DM, and none of the patients experienced recurrence.

Conclusion

DM in these Chinese patients was similar to that observed in other DM populations in terms of immunophenotype and clinical and histological features. A notable absence in p53 staining was observed in the three cases reported here, suggesting that p53 negativity should not exclude the diagnosis of DM in the Chinese population.

The RAC1 Target NCKAP1 Plays a Crucial Role in the Progression of Braf;Pten-Driven Melanoma in Mice

BRAFV600E is the most common driver mutation in human cutaneous melanoma and is frequently accompanied by loss of the tumor-suppressing phosphatase PTEN. Recent evidence suggests a co-operative role for RAC1 activity in BRAFV600E-driven melanoma progression and drug resistance. However, the underlying molecular mechanisms and the role of RAC1 downstream targets are not well-explored. In this study, we examine the role of the NCKAP1 subunit of the pentameric cytoskeletal SCAR/WAVE complex, a major downstream target of RAC1, in a mouse model of melanoma driven by BRAFV600E;PTEN loss. The SCAR/WAVE complex is the major driver of lamellipodia formation and cell migration downstream of RAC1 and depends on NCKAP1 for its integrity. Targeted deletion of Nckap1 in the melanocyte lineage delayed tumor onset and progression of a mutant Braf;Pten loss‒driven melanoma mouse model. Nckap1-depleted tumors displayed fibrotic stroma with increased collagen deposition concomitant with enhanced immune infiltration. Nckap1 loss slowed proliferation and tumor growth, highlighting a role in cell-cycle progression. Altogether, we propose that NCKAP1-orchestrated actin polymerization is essential for tumor progression and maintenance of tumor tissue integrity in a mutant Braf/Pten loss‒driven mouse model for melanoma.

Total saponins from Rubus parvifolius L. inhibits cell proliferation, migration and invasion of malignant melanoma in vitro and in vivo

Background: Total saponins from Rubus parvifolius L. (TSRP) are the main bioactive fractions responsible for the anti-tumor activities. The work was aimed to evaluate the anti-tumor effect of TSRP in malignant melanoma (MM) in vitro and in vivo.

Methods and results: Anti-melanoma cell proliferation, invasion and migration effect of TSRP were detected in human MM A375 cells under the indicated time and dosages. In vivo anti-tumor effect of TSRP was measured in A375 xenograft immunodeficient nude mice. Sixty A375 xenografts were randomly divided into five groups: Vehicle, cyclophosphamide (CTX, 20 mg/kg), TSRP (25 mg/kg), TSRP (50 mg/kg) and TSRP (100 mg/kg) groups for 14 days’ treatment. In addition, the melanoma metastasis in lung in vivo of TSRP was detected in A375 tail vein injection mice, and the histopathalogical analysis of the lung metastasis was detected by Hematoxylin–Eosin (H&E) staining. TSRP significantly inhibited the cell proliferation, invasion and migration of A375 in vitro at the indicated time and dosages. TSRP treatment effectively blocked the tumor growth in immunodeficient nude mice. In addition, TSRP also significantly inhibited the lung metastasis of melanoma.

Conclusion: The present study indicated that the TSRP has a remarkable anti-MM effect, which mainly through the inhibition of the cell invasion, migration and tumor metastasis.

Emerging strategies to treat rare and intractable subtypes of melanoma

Melanoma is the deadliest form of skin cancer, possessing a diverse landscape of subtypes with distinct molecular signatures and levels of aggressiveness. Although immense progress has been achieved therapeutically for patients with the most common forms of this disease, little is known of how to effectively treat patients with rarer subtypes of melanoma. These subtypes include acral lentiginous (the rarest form of cutaneous melanoma; AL), uveal, and mucosal melanomas, which display variations in distribution across (a) the world, (b) patient age-groups, and (c) anatomic sites. Unfortunately, patients with these relatively rare subtypes of melanoma typically respond worse to therapies approved for the more common, non-AL cutaneous melanoma and do not have effective alternatives, and thus consequently have worse overall survival rates. Achieving durable therapeutic responses in these high-risk melanoma subtypes represents one of the greatest challenges of the field. This review aims to collate and highlight effective preclinical and/or clinical strategies against these rare forms of melanoma.

Lentigo Maligna: Clinical Presentation and Appropriate Management

Lentigo maligna (LM) is a type of melanoma in situ that has distinctive characteristics regarding epidemiology, risk factors and clinical features. In addition, LM has a potential to progress to an invasive tumor with potentially aggressive behavior: lentigo maligna melanoma (LMM). Overall, LM has a very good prognosis, whereas LMM has the same prognosis as other invasive melanomas with similar Breslow thickness. LM/LMM represents a challenging entity not only regarding the diagnosis but also regarding the management. Diagnostic criteria are not well established, and there is an overlap of clinical, dermoscopic and pathological features with other benign pigmented skin lesions such as lentigines, pigmented actinic keratoses or macular seborrheic keratoses. LM/LMM's common appearance within photodamaged skin makes lesion border identification difficult. Wide excisions are often required, but since LM/LMM typically appears on cosmetically sensitive areas such as the face, sometimes large excisions are not possible nor desirable. In this sense, specialized approaches have been developed such as margin-controlled surgery or image-guided treatment using reflectance confocal microscopy. Other treatments for LM such as cryosurgery, imiquimod, radiotherapy or photodynamic therapy have been proposed, although recurrence/persistence is common. The current manuscript reviews extensively the published data regarding the diagnosis, treatment and management of both complex entities LM and LMM.

Clinical size is a poor predictor of invasion in melanoma of the lentigo maligna type

BACKGROUND

There are no well-defined clinical factors to predict the risk of occult invasion in melanoma of the lentigo maligna type (LM) before complete histopathologic analysis.

OBJECTIVE

To evaluate whether clinical size was a predictor of invasion in LM and subclinical extension.

METHODS

Consecutive cases of LM were recorded in a prospectively maintained database from 2006 to 2019. Patient and tumor data were recorded during initial evaluation. The LM clinical area was calculated in square millimeters (length × width). All patients were treated with staged excision.

RESULTS

We included 600 patients. The mean age was 65.9 years (standard deviation, 12.3; range, 27-95 years); 62.8% (n = 377) were men. The mean LM clinical area was 128.32 mm² for in situ lesions versus 200.14 mm for invasive lesions (P = .1). Based on quantile regression, the median margin required for complete removal increased with LM clinical area.

LIMITATIONS

The study was performed in a tertiary cancer center with possible referral bias and more complex cases.

CONCLUSIONS

LM can present with variable clinical size, which may correlate with subclinical extension; however, the presence of invasion is not well estimated by LM clinical area.

Frequency and prognosis of associated malignancies in 504 patients with lymphomatoid papulosis

Background

Lymphomatoid papulosis (LyP) can be associated with other haematological malignancies (HM), but reported percentages vary from 20% to over 50%.

Objective

To evaluate the frequency and prognostic significance of associated HM and non‐HM in LyP patients.

Methods

In this multicentre cohort study, the complete Dutch LyP population was included from the Dutch Cutaneous Lymphoma Registry between 1985 and 2018. Clinical and histopathological information was retrieved from every individual patient.

Results

After a median follow‐up of 120 months (range, 6–585), an associated HM was observed in 78/504 (15.5%) patients. Most common associated HM were mycosis fungoides (MF; n = 31) and anaplastic large‐cell lymphoma (ALCL; n = 29), while 19 patients had another HM of B‐cell (n = 14) or myeloid origin (n = 5). Even after a 25‐year follow‐up period, percentages of associated HM did not exceed 20%. Thirty‐nine of 465 patients (8.4%) without a prior or concurrent associated HM developed an associated HM during follow‐up, after a median of 68 months (range of 3–286 months). Nine of 78 patients died of associated HM, including 6/22 patients developing extracutaneous ALCL, while all patients with associated MF or skin‐limited ALCL had an excellent prognosis. Compared with the general population, LyP patients showed an increased risk (relative risk, 2.8; 95% confidence intervals, 2.4–3.3) for non‐HM, in particular cutaneous squamous cell carcinoma, melanoma and intestinal/lung/bladder cancer.

Conclusions

An associated HM was reported in 15.5% of the LyP patients, particularly MF and ALCL. Although the frequency of associated HM is lower than suggested and the prognosis of most patients with associated HM is excellent, a small subgroup will develop aggressive disease, in particular extracutaneous ALCL. Furthermore, LyP patients have a higher risk of developing other malignancies. Clinicians should be aware of these risks, and LyP patients require close monitoring.

Linked article: F. Rongioletti. J Eur Acad Dermatol Venereol 2020; 34: 216–217. https://doi.org/10.1111/jdv.16157.