Utilizing deep learning model for assessing melanocytic density in resection margins of lentigo maligna.

BACKGROUND: Surgical excision with clear histopathological margins is the preferred treatment to prevent progression of lentigo maligna (LM) to invasive melanoma. However, the assessment of resection margins on sun-damaged skin is challenging. We developed a deep learning model for detection of melanocytes in resection margins of LM. METHODS: In total, 353 whole slide images (WSIs) were included. 295 WSIs were used for training and 58 for validation and testing. The algorithm was trained with 3,973 manual pixel-wise annotations. The AI analyses were compared to those of three blinded dermatopathologists and two pathology residents, who performed their evaluations without AI and AI-assisted. Immunohistochemistry (SOX10) served as the reference standard. We used a dichotomized cutoff for low and high risk of recurrence (≤ 25 melanocytes in an area of 0.5 mm for low risk and > 25 for high risk). RESULTS: The AI model achieved an area under the receiver operating characteristic curve (AUC) of 0.84 in discriminating margins with low and high recurrence risk. In comparison, the AUC for dermatopathologists ranged from 0.72 to 0.90 and for the residents in pathology, 0.68 to 0.80. Additionally, with aid of the AI model the performance of two pathologists significantly improved. CONCLUSIONS: The deep learning showed notable accuracy in detecting resection margins of LM with a high versus low risk of recurrence. Furthermore, the use of AI improved the performance of 2/5 pathologists. This automated tool could aid pathologists in the assessment or pre-screening of LM margins.

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.

Radiation and Melanoma: Where Are We Now?

PURPOSE OF REVIEW: This review summarizes the current role of radiotherapy for the treatment of cutaneous melanoma in the definitive, adjuvant, and palliative settings, and combinations with immunotherapy and targeted therapies. RECENT FINDINGS: Definitive radiotherapy may be considered for lentigo maligna if surgery would be disfiguring. High risk, resected melanoma may be treated with adjuvant radiotherapy, but the role is poorly defined since the advent of effective systemic therapies. For patients with metastatic disease, immunotherapy and targeted therapies can be delivered safely in tandem with radiotherapy to improve outcomes. Radiotherapy and modern systemic therapies act in concert to improve outcomes, especially in the metastatic setting. Further prospective data is needed to guide the use of definitive radiotherapy for lentigo maligna and adjuvant radiotherapy for high-risk melanoma in the immunotherapy era. Current evidence does not support an abscopal response or at least identify the conditions necessary to reliably produce one with combinations of radiation and immunotherapy.

Extrafacial lentigo maligna: A progression model and enhanced diagnostic techniques using dermatoscopy and reflectance confocal microscopy.

Lentigo maligna (LM) is a subtype of lentiginous melanoma confined to the epidermis, which is associated with chronic sun exposure. Its clinical, dermatoscopic, and histopathological diagnosis can be challenging, particularly in the early and advanced stages, requiring appropriate clinicopathological correlation. This article reviews the clinical presentation, diagnosis through noninvasive methods (dermoscopy and confocal microscopy), and provides insights for diagnosis of extrafacial LM through the presentation of four representative clinical cases from different phases of a theoretical-practical progression model. Recognizing these lesions is crucial, as once they invade the dermis, they can behave like any other type of melanoma.

Double Immunohistochemical Labelling of PRAME and Melan A in Slow Mohs Biopsy Margin Assessment of Lentigo Maligna and Lentigo Maligna Melanoma.

Introduction: Lentigo maligna (LM) and lentigo maligna melanoma (LMM) predominantly affect the head and neck areas in elderly patients, presenting as challenging ill-defined pigmented lesions with indistinct borders. Surgical margin determination for complete removal remains intricate due to these characteristics. Morphological examination of surgical margins is the key form of determining successful treatment in LM/LMM and underpin the greater margin control provided through the Slow Mohs micrographic surgery (SMMS) approach. Recent assessments have explored the use of immunohistochemistry (IHC) markers, such as Preferentially Expressed Antigen in Melanoma (PRAME), to aid in LM/LMM and margin evaluation, leveraging the selectivity of PRAME labelling in malignant melanocytic neoplasms. Methods: A Novel double-labelling (DL) method incorporating both PRAME and MelanA IHC was employed to further maximise the clinical applicability of PRAME in the assessment of LM/LMM in SMMS biopsies. The evaluation involved 51 samples, comparing the results of the novel DL with respective single-labelling (SL) IHC slides. Results: The findings demonstrated a significant agreement of 96.1% between the DL method and SL slides across the tested samples. The benchmark PRAME SL exhibited a sensitivity of 91.3% in the SMMS specimens and 67.9% in histologically confirmed positive margins. Discussion: This study highlights the utility of PRAME IHC and by extension PRAME DL as an adjunctive tool in the assessment of melanocytic tumours within staged excision margins in SMMS samples.

Nevus-associated Lentigo Maligna and Lentigo Maligna Melanoma, Clinicopathological Features.

Nevus-associated lentigo maligna and lentigo maligna melanoma (NALMM) are rarely described in the literature and are considered an incidental finding. This study aimed to evaluate the frequency of NALMM and its clinicopathological features. A total of 201 histopathology reports were reviewed and among them 20% of the samples corresponded to NALMM, with females overrepresented in this group (p = 0.02). A significant association was also observed between NALMM with the presence of multiple nevi (p = 0.01), and dysplastic nevi (p = 0.04). Moreover, the risk of developing a second melanoma of nevus-associated type was 4.3 times higher in patients with NALMM. These results indicate that NALMM is more frequent than previously reported, suggesting that the associated nevus could interact or even act as a precursor for LM/LMM. Future studies with larger samples allied to techniques like confocal microscopy and molecular analysis are essential to determine this biological link between nevus and LM/LMM.

Review on the Role of Paraffin-embedded Margin-controlled Mohs Micrographic Surgery to Treat Skin Tumors. / [Artículo traducido] Revisión del rol de la cirugía micrográfica con cortes en parafina en el tratamiento de tumores cutáneos.

Paraffin-embedded margin-controlled Mohs micrographic surgery (PMMS) includes various procedures such as slow Mohs or deferred Mohs technique, the Muffin and Tübingen techniques, and staged margin excision, or the spaghetti technique. PMMS is a variation of conventional Mohs micrographic surgery (MMS) that allows histopathological examination with delayed margin control. PMMS requires minimum training and may be adopted by any hospital. The setback is that PMMS can require procedures across multiple days. PMMS lowers the rate of recurrence of basal cell carcinoma vs wide local excision in high-risk basal cell carcinoma, and improves the rates of recurrence and survival in lentigo maligna. PMMS can be very useful in high-risk squamous cell carcinoma treatment. Finally, it is a promising technique to treat infrequent skin neoplasms, such as dermatofibrosarcoma protuberans, or extramammary Paget's disease, among others. In this article, we present a literature narrative review on PMMS, describing techniques and indications, and highlighting long-term outcomes.

Melanocyte Density in the Diagnosis of Melanoma In Situ in Sun-Damaged Skin.

ABSTRACT: Histologic differentiation between melanoma in situ in chronically sun-damaged skin (CSDS) [lentigo maligna (LM)] and CSDS without malignancy is difficult because signs of melanocyte activation and proliferation are found in both. A potentially reliable and quantifiable criterion is melanocyte density (MD). Here, we evaluated whether and to what extent MD allows the distinction between LM and CSDS, which is particularly relevant for the evaluation of borderline cases and surgical margins.Articles assessing MD in LM and/or CSDS were evaluated in a systematic review. The results were categorized and compared according to staining. Cutoff values were included whenever stated.Twenty articles matched the selection criteria. Six hundred forty-four samples of CSDS and 227 samples of LM were considered. In each individual study, mean MD scores were higher for LM than for CSDS. However, looking at the overall study situation, it becomes clear that the data are very heterogeneous and show overlaps. Therefore, no reliable orientation value can be derived. Only 1 article defined a cutoff value.The data of MD in LM in contrast to CSDS were sparse, and a defined cutoff value was only mentioned in 1 article for microphthalmia-associated transcription factor, which cannot yet be generalized. Especially regarding the importance for the definition of surgical resection margins, this unsatisfactory data set highlights the need for further studies. More precise diagnostic criteria could spare some patients extensive and possibly disfiguring surgery.

Review on the Role of Paraffin-embedded Margin-controlled Mohs Micrographic Surgery to Treat Skin Tumors.

Paraffin-embedded margin-controlled Mohs micrographic surgery (PMMS) includes various procedures such as slow Mohs or deferred Mohs technique, the Muffin and Tübingen techniques, and staged margin excision, or the spaghetti technique. PMMS is a variation of conventional Mohs micrographic surgery (MMS) that allows histopathological examination with delayed margin control. PMMS requires minimum training and may be adopted by any hospital. The setback is that PMMS can require procedures across multiple days. PMMS lowers the rate of recurrence of basal cell carcinoma vs wide local excision in high-risk basal cell carcinoma, and improves the rates of recurrence and survival in lentigo maligna. PMMS can be very useful in high-risk squamous cell carcinoma treatment. Finally, it is a promising technique to treat infrequent skin neoplasms, such as dermatofibrosarcoma protuberans, or extramammary Paget's disease, among others. In this article, we present a literature narrative review on PMMS, describing techniques and indications, and highlighting long-term outcomes.

Risk factors of lentigo maligna as compared to other melanoma subtypes.

BACKGROUND: Lentigo maligna (LM) exhibits a particular epidemiological profile compared to other histopathologic subtypes of melanoma, with a propensity for the head and neck area and a higher mean age at diagnosis. Few small-scale studies have exclusively evaluated the risk factors for the development of LM. OBJECTIVE: This study aims to compare LM to other histological subtypes of melanoma for the prevalence of known melanoma risk factors, including pigmentary characteristics, history of occupational sun exposure, nevus count, and familial melanoma history. PATIENTS AND METHODS: We conducted a case-control study of 152 patients with LM and 784 patients with other melanoma subtypes (OM). The Mann-Whitney t-test and Pearson chi-squared test were used to detect differences between the two groups in continuous and categorical variables, respectively. Univariate and multivariate logistic regression models were then constructed to identify risk factors for developing LM compared to other melanoma subtypes. RESULTS: In multivariate logistic regression analysis, LM was positively associated with a lentigines count >50 and occupational sun exposure compared to OM (OR 2.10, 95% CI 1.35-3.29 and OR 2.18, 95% CI 1.33-3.57, respectively). In contrast, patients with an increased nevus count and fair or medium skin color were less likely to develop LM than OM (OR 0.93, P < 0.001, 95% CI 0.91-0.94, and OR 0.28, P < 0.001, 95% CI 0.17-0.46, respectively). In univariate analysis, LM exhibited a weaker association with all pigmentary traits than OM. No significant associations were found for atypical nevi count and family history. CONCLUSION: We found significant differences in the prevalence of known melanoma risk factors between LM and other melanoma subtypes, which supports the hypothesis of a distinct pathogenetic pathway of LM.

Incidence trends of lentigo maligna and lentigo maligna melanoma in the United States from 2000 to 2019.

BACKGROUND: Information on lentigo maligna (LM) and lentigo maligna melanoma (LMM) in the 21st century is scarce. We aimed to elucidate the incidence of LM and LMM using the Surveillance, Epidemiology, and End Results (SEER) 17 Registries. METHODS: The data of patients diagnosed between 2000 and 2019 were extracted from the SEER database. The percentage of LM/LMM cases among all melanoma patients, age-standardized incidence rates, estimated annual percentage changes, and the cumulative incidence of LMM after LM were calculated. RESULTS: The SEER data yielded 95,175 patients with LM/LMM between 2000 and 2019. Cases of LM/LMM accounted for 15.7% of all melanomas. The age-standardized incidence per 100,000 person-years for LM increased from 4.16 to 5.61 and for LMM from 1.33 to 2.35 between 2000 and 2019. The annual increase in incidence of LM was 2.42%, and that of LMM was 3.32%. The cumulative incidence of LMM after a primary LM after 10-year follow-up was 0.94%. CONCLUSIONS: This study provides the first comprehensive analysis of the epidemiological status of LM/LMM in the United States in the 21st century using the population-based SEER data.

The combination of dermoscopy and reflectance confocal microscopy increases the diagnostic confidence of amelanotic/hypomelanotic lentigo maligna.

The dermoscopic diagnosis of amelanotic/hypomelanotic lentigo maligna/lentigo maligna melanoma (AHLM/LMM) may be very difficult in its early stages because of lack of pigment. Reflectance confocal microscopy (RCM) is an imaging technique that is especially helpful for the diagnosis of lentigo maligna. To determine the diagnostic performances of dermoscopy and RCM in the diagnosis of AHLM/LMMs we evaluated dermoscopic and RCM images of consecutive cases of histopathologically confirmed AHLM/LMMs, amelanotic/hypomelanotic basal cell carcinoma and squamous cell carcinoma (AHBCCs/AHSCCs), amelanotic/hypomelanotic benign lesions (AHBLs), and actinic keratoses (AKs) from five participating centers. Sensitivity, specificity, accuracy, predictive values, and level of diagnosis confidence were calculated for both diagnostic procedures. Both dermoscopy and RCM showed diagnostic performance >97% in the diagnosis of AHLM/LMMs versus AHBCC/AHSCCs and their combination slightly improved diagnostic performance, with accuracy increasing from 98.0% to 99.1%. Similarly, RCM in combination with dermoscopy showed a tiny increase in the diagnostic performance in the diagnosis of AHLM/LMMs versus AHBLs (accuracy increased from 87.2% to 88.8%) and versus AKs (accuracy increased from 91.4% to 93.4%). Although the increase in diagnostic performance due to RCM was modest, the combination of dermoscopy and RCM greatly increased the level of confidence; high confidence in the diagnosis of AHLM/LMMs versus AHBLs increased from 36.2% with dermoscopy alone to 76.6% with dermoscopy plus RMC. Based on our results, dermoscopy and RCM should be complementary to improve not only diagnostic accuracy but also the level of diagnostic certainty in the diagnosis of AHLM/LMMs.

Perifollicular linear projections: A dermatoscopic criterion for the diagnosis of lentigo maligna on the face.

BACKGROUND: Lentigo maligna (LM) can mimic benign, flat, pigmented lesions and can be challenging to diagnose. OBJECTIVE: To describe a new dermatoscopic feature termed "perifollicular linear projections (PLP)" as a diagnostic criterion for LM on the face. METHODS: Retrospective study on reflectance confocal microscopy and dermatoscopy images of flat facial pigmented lesions originating from 2 databases. PLP were defined as short, linear, pigmented projections emanating from hair follicles. Dermatoscopy readers were blinded to the final histopathologic diagnosis. RESULTS: From 83 consecutive LMs, 21/83 (25.3%) displayed "bulging of hair follicles" on reflectance confocal microscopy and 18 of these 21 (85.7%), displayed PLP on dermatoscopy. From a database of 2873 consecutively imaged and biopsied lesions, 252 flat-pigmented facial lesions were included. PLP was seen in 47/76 melanomas (61.8%), compared with 7/176 lesions (3.9%) with other diagnosis (P < .001). The sensitivity was 61.8% (95% CI, 49.9%-72.7%), specificity 96.0% (95% CI, 92.9%-98.4%). PLP was independently associated with LM diagnosis on multivariate analysis (OR 26.1 [95% CI, 9.6%-71.0]). LIMITATIONS: Retrospective study. CONCLUSION: PLP is a newly described dermatoscopic criterion that may add specificity and sensitivity to the early diagnosis of LM located on the face. We postulate that PLP constitutes an intermediary step in the LM progression model.

Case of large lentigo maligna melanoma of the scalp treated with 5% and 3. 75% Imiquimod

Abstract The paper presents a case of lentigo maligna melanoma of the scalp in an elderly patient treated for the nodular part with surgery and the residual melanoma in situ with 5% Imiquimod and subsequently with 3.75% Imiquimod (each concentration for 4 months, 5 times per week), with complete regression of the lesion. 3.75% Imiquimod, which is already used for the treatment of actinic keratosis, could be a useful weapon with the same effectiveness and fewer side effects compared to 5% Imiquimod.

Uso da técnica em "spaghetti" para tratamento cirúrgico do lentigo maligno / Use of the "spaghetti" technique for surgical treatment of lentigo maligna

O lentigo maligno (LM) é uma forma de melanoma in situ que mais comumente se apresenta como uma mácula de crescimento lentamente progressivo, pigmentada, na face de idosos com pele danificada pelo sol. Esse melanoma in situ tem um risco (30% a 50%) de progressão para lentigo maligno melanoma. A excisão cirúrgica completa da lesão requer margens de pelo menos 10mm, mesmo para lesões in situ. Porém, quando o crescimento de LM ocorre em áreas de implicações estéticas ou funcionais (face, pescoço, solas), a excisão é frequentemente reduzida para preservar estruturas anatômicas importantes e por razões cosméticas. Além disso, as margens periféricas podem ser clinicamente mal definidas e nem sempre pigmentadas, com extensão subestimada e risco de ressecção insuficiente. A "técnica de espaguete", descrita por Gaudy Marqueste, é uma cirurgia estratégica baseada na amostragem de uma faixa de tecido "spaghettilike" para determinar as margens da lesão antes da remoção do tumor. Após a confirmação anatomopatológica de margens livres de neoplasia, a lesão principal central é ressecada, permitindo a reconstrução do defeito no mesmo procedimento, sendo uma alternativa à cirurgia micrográfica de Mohs.(AU)

Lentigo maligna (LM) is a melanoma in situ that commonly presents as a macula with progressive and irregularly pigmented growth, especially in the face of elderly people with sun-damaged skin. This melanoma in situ has a risk (30-50%) of progression to lentigo maligna melanoma. Complete surgical excision of the lesion requires margins of at least 10 mm, even for lesions in situ. However, when the growth of LM occurs in areas of aesthetic or functional implications (face, neck, and soles), the excision is often reduced to preserve important anatomic structures and for cosmetic purposes. Moreover, the peripheral margins may be clinically ill-defined and not always pigmented, and thus, such cases are associated with underestimated extension and risk of insufficient resection. The "spaghetti" technique, described by Gaudy Marqueste, is a strategic surgical approach based on sampling of a range of "spaghetti-like" strips to determine the margins of the lesion prior to removal of the tumor. After the pathological confirmation of neoplasia-free margins, the main central lesion is resected, allowing reconstruction of the defect in the same procedure, as an alternative to Mohs micrographic surgery. (AU)

Avaliação das lesões pigmentadas e isoladas da face por microscopia confocal: desenvolvimento de um nomograma preditivo de melanoma / Reflectance confocal microscopy of pigmented and isolated face lesions: a predictive nomogram for melanoma

INTRODUÇÃO: O lentigo maligno (LM) é o subtipo do melanoma mais comum da face. O LM apresenta-se clinicamente como uma mácula acastanhada na sua fase inicial, sendo difícil sua diferenciação com lesões pigmentadas benignas da face ao exame clínico. A face, por apresentar particularidades anatômicas e histológicas, pode dificultar o diagnóstico do LM ao diferenciá-lo dos seus simuladores (ceratose actínica pigmentada, ceratose líquen plano-like, lentigo solar, ceratose seborreica). A microscopia confocal in vivo (MC) auxilia no diagnóstico das lesões dermatológicas em que a dermatoscopia possui limitação, permitindo assim, aumentar a acurácia diagnóstica e evitar procedimentos invasivos em lesões benignas, de maneira desnecessária. OBJETIVOS: Descrever as alterações celulares e arquiteturais significativas no exame de MC nas lesões isoladas da face para o diagnóstico de melanoma. Elaborar um método diagnóstico acurado utilizando os critérios da microscopia confocal. MÉTODOS: Estudo prospectivo e retrospectivo com amostragem não aleatória consecutiva no qual foram incluídos 105 pacientes com lesões pigmentadas solitárias da face provenientes do Núcleo de Câncer de Pele A.C.Camargo Cancer Center. Critérios avaliados na MC: padrão em "favo de mel" típico ou atípico; células dendríticas; células nucleadas redondas; disseminação pagetóide, Sheets of cells; ninhos celulares densos e homogêneos (típico) ou denso e esparsos, com atipias (atípico); célula nucleada redonda ou dendrítica na junção dermo-epidérmica; células dendríticas foliculares (célula dendrítica no epitélio folicular) e cords ou projeções bulbosas; ilhas tumorais e fendas. O teste Exato de Qui Quadrado foi aplicado aos critérios da MC. Regressão Logística Univariada foi realizada através de estimativas de risco pelo Odds Ratio. Foi realizado a Regressão Logística Múltipla, resultando em um Nomograma para quantificar, em porcentagem, a chance de ter o diagnóstico de melanoma de acordo com a presença, singular ou concomitante, dos critérios da microscopia confocal supracitados. RESULTADOS: Os critérios da MC célula redonda atípica nucleada na epiderme, célula dendrítica nucleada na epiderme, disseminação pagetóide, célula atípica na JDE, ninhos juncionais atípicos, célula dendrítica folicular, sheets of cells e ilhas tumorais ou silhuetas escuras apresentaram significância estatística (p<0,05). Enquanto que os critérios cords ou projeções bulbosas e padrão em favo de mel atípico não tiveram significância. O único critério que apresentou-se como fator protetor pelo odds ratio foi a presença de ilhas tumorais ou silhuetas escuras. A Regressão Logística Múltiplo resultou em 3 critérios: célula redonda nucleada na epiderme, disseminação pagetóide e célula dendrítica folicular. A partir destes dados, foi realizado o nomograma para definir a chance, em percentual, de ter o diagnóstico de melanoma de acordo com a presença ou ausência das alterações celulares encontradas na microscopia confocal. A presença destes 3 critérios concomitantes expressa 98% de probabilidade da lesão ser melanoma. CONCLUSÃO: Este estudo viabilizou uma estimativa de probabilidade por intermédio de um percentual executável para o referido diagnóstico de melanoma da face, de acordo com a presença, ausência e concomitância destes critérios, de maneira prática e factível à aplicação no cotidiano do consultório

INTRODUCTION: Lentigo maligna (LM) is the most common subtype of facial melanoma. LM presents clinically as a brownish macule in its initial phase, and it is a challenge to differentiate from others facial benign pigmented lesions. Anatomical and histological face's features may make difficult to diagnose LM and to distinguish it from its simulators (actinic keratosis, lichen planus-like queratosis, solar lentigo, seborrheic keratosis). In vivo reflectance confocal microscopy (RCM) assists in the diagnosis of dermatological lesions in which dermatoscopy is limited, allowing to increase diagnostic accuracy and avoid invasive procedures in benign lesions, unnecessarily. OBJECTIVES: Describe cellular and architectural characteristics that were significant in the RCM examination in lesions face for the diagnosis of melanoma. Also elaborate an accurate diagnostic method using the criterias of RCM. METHODS: A prospective and retrospective study with consecutive non-random sampling with 105 patients presenting solitary pigmented facial lesions from the A.C.Camargo Cancer Center Skin Center. RCM criteria: typical or atypical honeycomb; dendritic cells; round nucleated cells; pagethoid spread, Sheets of cells; nests dense and homogeneous (typical) or dense and sparse (atypical); round or dendritic nucleated cell at the dermo-epidermal junction; follicular dendritic cells (dendritic cell in the follicular epithelium) and bulbous cords or projections; tumor islands and dark silluets. The exact test of Chi Square was applied to the criteria of RCM. Univariate Logistic Regression was performed through risk estimates by the Odds Ratio. Multiple Logistic Regression model was performed, resulting in a Nomogram to quantify, in percentage, the chance of having the diagnosis of melanoma according to the singular or concomitant presence of the above mentioned RCM criteria. RESULTS: RCM criteria atypical round cell nucleated in the epidermis, nucleated dendritic cell in the epidermis, pagethoid spread, atypical cell in the JDE, atypical junctional nodes, follicular dendritic cell, sheets of cells and tumor islands or dark silhouettes presented statistical significance (p <0.05). While the criteria cords or projections bulbous and standard in atypical honeycomb had no significance. The only criterion that presented itself as a protective factor by odds ratio was tumor islands or dark silhouettes. The Multiple Logistic Regression resulted in 3 criteria: nucleated round cell in the epidermis, pagetoid spread and follicular dendritic cell. From these data, the nomogram was used to define the percentage chance of having the diagnosis of melanoma according to the presence or absence of cellular alterations found in RCM. The presence of these 3 concomitant criteria expresses 98% probability of the lesion being a melanoma. CONCLUSION: This study enabled estimate probability for the diagnosis of facial melanoma, according to the presence, absence and concomitance of RCM criteria, in a practical and feasible way to the daily medical practice