Lentigo Maligna Melanoma Research Articles

DS03 Lentigo maligna: is it time to put down the scalpel?

Abstract Lentigo maligna (LM) is a subtype of melanoma in situ that often proves to be a diagnostic and therapeutic challenge. Treatment aims to prevent progression to an invasive tumour called lentigo maligna melanoma (LMM). In the UK, common treatment modalities include conventional excision, staged re-excisions, slow Mohs surgery or expectant monitoring. Although considered the ‘gold standard’, surgical excision of LM can be disfiguring as it frequently affects cosmetically sensitive areas requiring complex surgical reconstructions. Topical imiquimod 5% presents a pragmatic alternative treatment modality without the need for surgery. In vivo reflectance confocal microscopy (RCM) allows real-time noninvasive delineation of LM. Evidence suggests this is an effective diagnostic tool for pre- and post-treatment evaluation (Brand FL, Jafari SM, Hunger RE. Confocal microscopy and lentigo maligna: an in vivo pilot study for the assessment of response to imiquimod therapy. Dermatology 2019; 235:150–5). We retrospectively analysed 35 cases of histologically confirmed LM that completed treatment with imiquimod between 2018 and 2022. The average patient age at diagnosis was 73.9 years, with a female : male ratio of 18 : 17. Following assessment with RCM, patients were prescribed a protocol of topical imiquimod 5% once a day, 5 days per week for 12 weeks, along with instructions to apply this 10 mm beyond the mapped area or a cosmetic unit (Australia and New Zealand Melanoma Trials Group RADICAL trial). Patients were counselled about expected side-effects; all completed the course and achieved significant inflammation and superficial ulceration. To ensure a response was achieved, the following stepwise interventions were used: application increased to 7 days per week, occlusion with a dressing and addition of a topical retinoid. Repeat RCM was performed 6 months after treatment completion. At this point, 30 of 35 (86%) patients responded with no evidence of residual LM on RCM. Three cases required a second course of treatment. Two of these were shown to be clear on RCM, while the third is clinically clear and awaiting RCM confirmation. A fourth patient was lost to follow-up. A further patient has failed two courses and is about to embark on a third round of treatment. In total, 16 cases completed the 12-month review and maintained clearance. We demonstrate that imiquimod is an effective treatment for LM, potentially avoiding extensive surgery and complex reconstruction. Reflectance confocal microscopy can be used to delineate the extent of the LM and assess the post-treatment response. Our preliminary data suggest a significant proportion of LM cases achieved clearance with no recurrences to date. Follow-up of these patients will help evaluate the long-term efficacy of imiquimod, but our data suggest this treatment protocol provides a promising alternative to surgical intervention.

The role of histological subtypes in the survival of patients diagnosed with cutaneous or mucosal melanoma in the United States of America.

Literature presents limited information on histological subtypes and their association with other factors influencing the survival of melanoma patients. To explore the risk of death due to melanoma associated with histological subtypes, this retrospective study used the Surveillance, Epidemiology, and End Results program (SEER) data from 1998 to 2019. A total of 27,532 patients consisting of 15,527 males and 12,005 females. The Hypertabastic Accelerated Failure Time model was used to analyze the impact of histology on the survival of patients with cutaneous or mucosal melanoma. The median survival time (MST) for cutaneous patients was 149 months, whereas those diagnosed with mucosal melanoma was 34 months. Nodular melanoma had a hazard ratio of 3.40 [95% CI: (2.94, 3.94)] compared to lentigo maligna melanoma. Across all histological subtypes, females had a longer MST, when compared to males. The hazard ratio (HR) of distant to localized melanoma was 9.56 [95% CI: (7.58, 12.07)]. Knowledge of patients' histological subtypes and their hazard assessment would enable clinicians and healthcare providers to perform personalized treatment, resulting in a lower risk of complication and higher survivability of melanoma patients. Significant factors were stage of the disease, age, histology, sex, and income. Focus should be placed on high-risk populations with severe and aggressive histological subtypes. Programs that emphasize preventive measures such as awareness, education, and early screening could reduce risk.

Clinicopathological Profile of a Cohort of Patients With Malignant Melanoma in the United Kingdom.

Introduction Malignant melanoma (MM) is potentially a fatal type of skin cancer and a major health concern for the Caucasian population. It is a heterogeneous disease with a wide spectrum of manifestations. Therefore, in this study, we evaluated the clinicopathological characteristics of MM. Methods We retrospectively studied the clinicopathological characteristics of MM in 167 biopsy-proven cases of MM reported between January 2020 and December 2021 at Kings Mill Hospital, Sutton-in-Ashfield, United Kingdom. Clinical data such as the age, sex, and anatomical site of the lesion were obtained from the clinical referral forms. Biopsies of the lesions were performed, and the specimens collected were sent to the laboratory for histopathological study and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation evaluation. Formalin-fixed paraffin-embedded blocks (FFPE) were prepared, sectioned, and stained with hematoxylin and eosin for histological examination. Results A total of 167 cases of MM were included in the study. The age range was 23-96 years, with the median age at diagnosis found to be 66 years; males were more commonly affected (52.1%). The median Breslow thickness was 1.20 mm. The median mitotic activity was 1.0/mm2. The lower limb was the most common site of involvement (27.5%), followed by the thorax (25.1%). The most common histological subtype was superficial spreading melanoma (SSM) (77.8%), followed by nodular melanoma (14.4%). The in situ component was present in 95.8% of cases; a majority (92.2%) of the cases showed vertical growth phase, 71.9% of cases were at Clark's level IV of invasion, regression was noted in 70.7% of cases, ulceration was present in 21.6% of cases, and microsatellites were present in 3% of cases. Perineural invasion was present in 3% of cases, and lymphovascular invasion (LVI) was present in 4.2% of cases. BRAF mutation testing was performed on 36 cases, out of which 20 cases (55.6%) showed BRAF mutation. Acral lentiginous melanoma and nodular melanoma were most likely to show ulceration (66.7% and 37.5%, respectively). SSM and lentigo maligna melanoma were more likely to be associated with regression. Conclusion The study demonstrated that MM is prevalent among the elderly population with male predominance; SSM was found to be the most common subtype. The study further demonstrated various clinicopathological features of MM and its association with histological subtypes.

Efficacy of imiquimod in the management of lentigo maligna.

Lentigo maligna (LM) is a melanocytic proliferation occurring on photo-exposed skin that may progress to LM melanoma. Surgery is recommended as first-line treatment. Excision margins of 5-10 mm remain, without international consensus. Several studies have shown that imiquimod, an immunomodulator, induces LM regression. This study investigated the effect of imiquimod versus placebo in neoadjuvant settings. We performed a prospective, randomized, multicentre, phase III clinical study. Patients were randomly assigned in 1:1 ratio to receive imiquimod or placebo for 4 weeks, followed by LM excision 4 weeks after the last application of imiquimod or placebo. The primary endpoint was extra-lesional excision, with a 5 mm margin from the residual pigmentation after imiquimod or vehicle. Secondary endpoints included the gain on the surface removed between the two groups; number of revision surgeries to obtain extra-lesional excisions; relapse-free time; and number of complete remissions after treatment. A total of 283 patients participated in this study; 247 patients, 121 patients in the placebo group and 126 in the imiquimod group, accounted for the modified ITT population. The first extralesional extirpation was performed in 116 (92%) imiquimod patients and in 102 (84%) placebo patients; the difference was not significant (p = 0.0743). Regarding the surface of LM, imiquimod reduced the LM surface (4.6-3.1 cm2 ) significantly (p < 0.001) more compared to the placebo (3.9-4.1 cm2 ). Imiquimod reduces the lentigo maligna surface after 1 month of treatment, without a higher risk of intralesional excision and with a positive aesthetic outcome.

Surgical margin mapping for lentigo maligna and lentigo maligna melanoma: traditional technique (visual inspection with dermoscopy) versus combined paper tape and reflectance confocal microscopy technique.

The detection of subclinical margin in lentigo maligna/lentigo maligna melanoma (LM/LMM) can be challenging for the dermatologist. Reflectance confocal microscopy (RCM) enables to observe in vivo atypical melanocytes beyond the clinical margins. The aim of this study is to establish which of these methods (clinical examination and dermoscopy versus "Paper tape - RCM") is more precise to define the lesion margin and to reduce the number of re-intervention and overtreatments in cosmetically sensitive areas. Fifty-seven cases of LM/LMM were analyzed during 2016-2022. Pre-surgical mapping procedures in 32 lesions were effectuated with dermatoscopy. Furthermore, pre-surgical mapping procedures in 25 lesions were effectuated with RCM and paper tape. RCM method's accuracy to detect subclinical margins was 92.0%. In 24 of 25 cases, the lesions were excised completely during the first intervention. In 20 of 32 cases analyzed with dermoscopy, a second surgical intervention was effectuated. The RCM paper method allows us to delineate subclinical margin more accurately and reduce overtreatment, especially in sensitive areas, such as the face and neck.

Association of Excision Margin Size With Local Recurrence and Survival in Patients With T1a Melanoma at Critical Structures

Melanoma guidelines recommend surgical excision with 10-mm margins for T1 melanoma. However, this procedure may be problematic at sites close to critical structures such as the scalp, face, external genitalia, acral, periumbilical, and perineal areas. To compare outcomes of wide (10-mm margins) vs narrow (5-mm margins) excision in patients with T1a melanoma near critical structures. This cohort study was a retrospective comparison of 1341 consecutive patients aged 18 years or older from the National Cancer Institute of Milan, Italy, diagnosed between 2001 and 2020 with T1a cutaneous melanoma close to critical structures who accepted wide excision vs narrow excision. Local recurrence and melanoma-specific mortality (MSM) rates with 5-mm vs 10-mm excision margins. The primary aim of the study was to ascertain whether a narrower (5-mm) vs wider (10-mm) excision margin was associated with local recurrence and MSM. The secondary aim was to compare the need for reconstructive surgery in the groups defined by excision margin width. Between April 28 and August 7, 2022, associations were assessed by weighted Cox and Fine-Gray univariable and multivariable models. A total of 1179 patients met the inclusion criteria (median [IQR] age, 50.0 [39.5-63.0] years; female, 610 [51.7%]; male, 569 [49.3%]). Six hundred twenty-six patients (53.1%) received a wide excision (434 [69.3%] with linear repair and 192 [30.7%] with flap or graft reconstruction) and 553 (46.9%) received a narrow excision (491 [88.8%] with linear repair and 62 [11.2%] with flap or graft reconstruction). The weighted 10-year MSM was 1.8% (95% CI, 0.8%-4.2%) in the wide group and 4.2% (95% CI, 2.2%-7.9%) in the narrow group; the weighted 10-year local recurrence rate was 5.7% (95% CI, 3.9%-8.3%) in the wide group and 6.7% (95% CI, 4.7%-9.5%) in the narrow group. Breslow thickness greater than 0.4 mm (subdistribution hazard ratio [sHR] for 0.6 vs 0.4 mm, 2.42; 95% CI, 1.59-3.68; P < .001) and mitotic rate greater than 1/mm2 (sHR for a single increment, 3.35; 95% CI, 2.59-4.32; P < .001) were associated with worse MSM. Multivariable analysis showed that acral lentiginous melanoma, lentigo maligna melanoma, and increasing Breslow thickness were associated with a higher incidence of local recurrence. The study's findings suggest that local excision with 5-mm margins for T1a melanoma may not be associated with an increased risk of local recurrence. Breslow thickness greater than 0.4 mm, mitotic rate greater than 1/mm2, and acral lentiginous melanoma and lentigo maligna melanoma subtypes were associated with a higher risk of recurrence. These findings may be useful for future melanoma treatment guidelines.

Similar local recurrence and survival in patients with T1 radial growth phase melanoma on head and neck treated with 5 or 10 mm margins: A retrospective study.

Melanoma guidelines recommend surgical excision with 10 mm margins for T1 melanomas (invasive melanomas with Breslow thickness ≤1 mm), including those in radial growth phase, which are without metastatic potential; however, such margins may be problematic on head-and-neck. We compared outcomes of wide (10 mm margins) versus narrow (5 mm margins) excisions in patients with radial growth phase T1 melanoma on head-and-neck including face. We retrospectively examined 610 consecutive patients excised with wide versus narrow margins, from 2001 to 2018, at six European centres. In all cases, radial growth phase, and clear margins with 5 or 10 mm of clearance, were ascertained histologically. Multivariable models investigated associations of margins and other factors with overall survival and local recurrence. Three hundred and sixteen (51.8%) patients received wide excision, 219 (69.3%) with primary wound closure, 97 (30.7%) with reconstruction; 294 (48.2%) patients received narrow excision, 264 (89.8%) with primary wound closure, 30 (10.2%) with reconstruction (p < 0.001). Median follow-ups were 88 months (wide) and 187 months (narrow) (inter-quartile ranges 43-133 and 79-206, respectively). Ten-year overall survival (95% confidence interval) was 96.7% (94.2%-99.3%) in wide and 98.2% (96.4%-100%) in narrow patients. Ten-year local recurrence incidence was 6.4% (4.1%-10.1%) in wide and 7.8% (5.3%-11.6%) in narrow groups. Lentigo maligna melanoma subtype appeared associated with increased risk of local recurrence in narrow versus wide patients (15.0% vs. 7.5%; p=0.190). Narrower excision margins for T1 radial growth phase melanoma are not associated with worse overall survival (hazard ratio 0.97, p=0.996) or increased local recurrence (subdistribution hazard ratio: 0.87; p=0.751) compared to wider margins, and may be safely applied to such lesions, although caution may be required in the presence of lentigo maligna melanoma.

Factors Influencing General Dermatologists When Referring Patients With Head and Neck Melanoma for Mohs Micrographic Surgery: A Nationwide Cross-Sectional Survey.

Mohs micrographic surgery (MMS) for cutaneous melanoma has demonstrated higher cure rates, lower local recurrence rates, and improved survival compared with wide local excision (WLE). However, factors affecting referrals by general dermatologists for MMS of head and neck melanoma (HNM) are unknown. To elucidate referral factors and treatment perspectives of general dermatologists regarding MMS for melanoma in situ (MIS)/lentigo maligna (LM) and early-stage melanoma on the head and neck. A cross-sectional analysis was performed using survey responses of general dermatologists with membership in the American Academy of Dermatology . A total of 231 and 132 of the 402 responding general dermatologists routinely referred melanoma in situ MIS/LM and early invasive melanoma for MMS, respectively. Lack of local access to a Mohs surgeon was the most common deterring reason for MIS/LM referral to MMS, whereas the preference for WLE was the most common deterring reason for early invasive melanoma. Lack of local access to a Mohs surgeon treating HNM with MMS is the primary barrier in referrals to Mohs surgeons for MIS and LM. Among general dermatologists, WLE is preferred for early invasive HNM.

Lentigo maligna and lentigo maligna melanoma in young patients in Australian tertiary centres.

This was a retrospective study of all patients with a diagnosis of lentigo maligna or lentigo maligna melanoma at 50 years of age or younger at the time of their first diagnosis in two Australian tertiary centres. The low recurrence rate in younger patients in this study warrants further investigation. Early diagnosis in young patients is crucial to allow early treatment and lifestyle changes to reduce actinic damage and subsequent development of further melanomas.

Genomic Profiling of Lentigo Maligna within an Interim Registry Analysis​

Background: Pigmented lesion analysis remains a challenging aspect of dermatology. The DermTech Melanoma Test (‘the test’) is a non-invasive genomic test designed to rule-out melanoma. It consists of the pigmented lesion assay, which detects RNA products of Long Intergenic Non-Coding RNA 00518 (LINC00518) and Preferentially Expressed Antigen in Melanoma (PRAME), and an add-on assay for DNA promoter mutations in telomerase reverse transcriptase (TERT). In previous studies, the test was found to have a negative predictive value ≥99%. This interim analysis of a registry study examines the genomic patterns of the Lentigo Maligna (LM) subtype of melanoma. Methods: Between April 2021 and March 2022, multiple geographically diverse sites throughout the US submitted data to a registry to assess real-world use of the test. Approximately 8,000 clinically atypical lesions were tested. After receiving the test result, providers followed their clinical judgement for biopsy decision. Histopathologic diagnoses for biopsied lesions were correlated with test results and all melanomas were sorted into LM subtype vs non-LM subtype. In addition, lesions that were noted to be on sun exposed skin and/or noted to have solar elastosis and called atypical melanocytic hyperplasia were included. Results: At the 1-year mark of the registry, there were roughly 8000 unique entries. Of those, 1003 expressed one or more genomic markers from the DMT and had records available, and 134 (13.2%) were found to be melanoma or melanoma in-situ. More than a third (n=46, 34.3%) of the melanomas were of the Lentigo Maligna sub-type, with 7 of those being Lentigo Maligna Melanoma (LMM). Seven additional lesions were called atypical junctional melanocytic hyperplasia (AJMH) on sun-damaged skin. This group of 53 LM, LMM, and AJMH lesions were all evaluated for correlations to the DMT markers. LINC was the most commonly expressed genomic marker (n=45, 84.9%), with PRAME (n=36, 67.9%) and TERT (n=24, 45.3%) following. Most invasive tumors (LMM) expressed all three markers (n=4) and all 7 expressed LINC. Conclusion: While the original validation study included the LM subtype, this interim registry analysis demonstrates real-world use of the DMT in assessing pigmented macules concerning for LM. Over 1/3 of the melanomas reported in the registry were LM subtypes. LINC had a higher correlation with the lentigo maligna subtype of melanoma and was present in all invasive tumors. While AJMH is considered borderline, it may be worthwhile in the clinical context to group AJMH lesions with LM due to similarities in treatment.

Long-term outcomes of margin-controlled excision for eyelid melanoma.

To provide evidence for long-term outcomes for margin-controlled excision of eyelid melanoma. Retrospective single-centre observational case series of patients treated for eyelid melanoma between 2007 and 2016, with a minimum of 5-year follow-up. Tumour excision involved rush-paraffin en face horizontal sections and delayed repair (Slow Mohs; SM). Twenty-two cases were seen with a survival of 91% (two deaths from nodular and lentigo maligna melanoma) and seven with melanoma in situ (MIS). Invasive melanoma includes eight lentigo maligna melanoma, four nodular, two amelanotic and one desmoplastic. Mean Breslow thickness was 6 mm for invasive (range 0.5-26). Mean excision margin for MIS was 3 mm (range 2-5 mm) and for invasive was 5 mm (range 2-10). Further excisions were performed in nine (41%); two went on to recur. Local recurrence was 36%; six invasive (27%) at a mean of 24 months (range 1.5-5 years) and two for MIS at a mean of 15 months (range 1-1.5 years). Imaging occurred for suspected advanced disease. Sentinel node biopsy was not performed. Advanced melanoma therapy was performed in two cases. No vitamin D testing occurred. Survival rates are in line with 90% overall survival in the UK. Prescriptive excision margins are not applicable in the periocular region and margin-controlled excision with a delayed repair is recommended, but patients need to know further excision may be needed to obtain clearance. Evidence recommending vitamin D therapy needs to be put into clinical practice. In addition, upstaging of MIS occurred advocating excision rather than observation of MIS. More studies are needed to determine the best management of eyelid melanoma.

Melanoma diagnosis at a specialist dermatology practice without the use of photographic surveillance.

Photographic aides are increasingly used in melanoma surveillance. We report melanoma characteristics detected using traditional surveillance without photographic technologies. Retrospective study of melanomas diagnosed by three dermatologists at a private dermatology practice over 7 years. Patients underwent full skin examinations with dermoscopy and suspect lesions were excised or biopsied. Total body photography (TBP) and serial digital dermoscopic imaging (SDDI) were not used. Patient demographics, melanoma subtype and thickness, location, biopsy technique and keratinocyte cancers diagnosed at the same visit were recorded. Ratio of in situ to invasive melanomas was calculated. Melanoma risk factors were recorded for 69 randomly-selected patients. 492 patients were diagnosed with 615 melanomas during 579 visits. 505 (82%) were in situ (in situ to invasive ratio of 4.6:1). Of the invasive melanomas, 85.5% had a Breslow thickness <0.8 mm, 10 (9.1%) 0.8-1 mm and 6 (5.5%) >1 mm. 43.3% of in situ melanomas were lentiginous or lentigo maligna and 41.6% were superficial spreading melanomas (SSM). Of invasive melanomas, 24.3% were lentigo maligna melanoma and 59.5% were SSM. 48.4% of melanomas were diagnosed by shave procedures. Where risk factors were known, 25% were very-high-risk and 43% had a history of melanoma. Keratinocyte carcinoma was diagnosed by biopsy at 26.1% of visits. Studies using TBP and/or SDDI report in situ to invasive ratios of 0.59:1 to 2.17:1. Tradiational melanoma surveillance with immediate biopsy of suspect lesions results in high in situ to invasive ratios. Studies using photographic surveillance show lower ratios of in situ to invasive disease.

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.

Lentigo maligna (melanoma): A systematic review and meta-analysis on surgical techniques and presurgical mapping by reflectance confocal microscopy.

Because of an increased risk of local recurrence following surgical treatment of lentigo maligna (melanoma) (LM/LMM), the optimal surgical technique is still a matter of debate. We aimed to evaluate the effect of different surgical techniques and reflectance confocal microscopy (RCM) on local recurrence and survival outcomes. We searched MEDLINE, Embase and PubMed databases through 20 May 2022. Randomized and observational studies with ≥10 lesions were eligible for inclusion. Bias assessment was performed using the Methodological Index for Non-Randomized Studies instrument. Meta-analysis was performed for local recurrence, as there were insufficient events for the other clinical outcomes. We included 41 studies with 5059 LM and 1271 LMM. Surgical techniques included wide local excision (WLE) (n=1355), staged excision (n=2442) and Mohs' micrographic surgery (MMS) (n=2909). Six studies included RCM. The guideline-recommended margin was insufficient in 21.6%-44.6% of LM/LMM. Local recurrence rate was lowest for patients treated by MMS combined with immunohistochemistry (<1%; 95% CI, 0.3%-1.9%), and highest for WLE (13%; 95% CI, 7.2%-21.6%). The mean follow-up varied from 27 to 63 months depending on surgical technique with moderate to high heterogeneity for MMS and WLE. Handheld-RCM decreased both the rate of positive histological margins (p < 0.0001) and necessary surgical stages (p < 0.0001). The majority of regional (17/25) and distant (34/43) recurrences occurred in patients treated by WLE. Melanoma-associated mortality was low (1.5%; 32/2107), and more patients died due to unrelated causes (6.7%; 107/1608). This systematic review shows a clear reduction in local recurrences using microscopically controlled surgical techniques over WLE. The use of HH-RCM showed a trend in the reduction in incomplete resections and local recurrences even when used with WLE. Due to selection bias, heterogeneity, low prevalence of stage III/IV disease and limited survival data, it was not possible to determine the effect of the different surgical techniques on survival outcomes.

Frequency and reliability of histologic subtype classification in invasive and in situ melanoma treated with Mohs micrographic surgery

To the Editor: National Comprehensive Cancer Network (NCCN) guidelines for melanoma state that Mohs micrographic surgery (MMS) may be considered for melanoma in situ (MIS) of lentigo maligna or acral lentiginous subtype or minimally invasive lentigo maligna melanoma subtype. NCCN guidelines also state that MMS may be considered for minimally invasive melanomas on specialty anatomic sites. It is unclear if indications for MMS are histologic subtype, anatomic site, or both.

Abstract C075: Increasing incidence of cutaneous malignant melanoma in the Hispanic population of the United States from 2006-2017

Abstract Melanoma is the fifth most commonly diagnosed cancer in the United States (US), and its incidence has been rapidly increasing within the past several decades. Previous studies have shown that individuals with darker skin tones are less likely to survive melanoma than those with lighter skin tones. Despite this increased morbidity in skin of color populations, limited studies have investigated how melanoma affects different races and ethnicities. Herein, we conducted a population-based registry study to assess the incidence and survival pattern of cutaneous malignant melanoma (CMM) subtypes in the US from 2006 to 2017. In addition, we examined the four major histological CMM subtypes (superficial spreading, lentigo maligna, nodular, and acral lentiginous melanoma) and its distribution by race, gender, and tumor grade. Data from 17 population-based cancer registries from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute were reviewed, and 58,666 histologically confirmed cases of CMM were evaluated. Acral lentiginous melanoma was diagnosed predominantly in non-Hispanic whites (56%) and Hispanic whites (45%). Melanomas that were not of the four major histological CMM subtypes were predominant in the Asian (54%) and Black (77%) populations. Superficial spreading and lentigo maligna melanomas presented more commonly in males (69% and 63%, respectively). Nodular and lentigo maligna melanomas had the poorest survival rates (median of 26 and 21 months, respectively). The incidence rate of CMM has been steadily increasing in the Hispanic population, with Hispanic whites having the highest incidence of acral lentiginous melanoma when compared to other skin of color populations. Thus, it is important we continue to assess and trend the epidemiological characteristics of CMM subtypes. In addition, future studies should investigate the possible genetic and environmental factors that may be contributing to the increased incidence of CMM in skin of color populations and its associated morbidity. Citation Format: Yae L. Kye, Cicilyn Xie, Hannah Riva, Michelle Samaniego, Fabiola Ramirez, Lorena Fernandez, Luis Alvarado, Alok Dwivedi, Jessica Chacon. Increasing incidence of cutaneous malignant melanoma in the Hispanic population of the United States from 2006-2017 [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C075.

Clinicopathologic Evaluation of CD80, CD86, and PD-L1 Expressions with Immunohistochemical Methods in Malignant Melanoma Patients.

Diagnostic and prognostic biomarkers for malignant melanoma are crucial for treatment and for developing targeted therapies. Malignant melanoma is a highly immunogenic tumor, and its regression, treatment, and prognostic evaluation are directly related to escape from immune destruction. Therefore, we aimed to determine the expression levels of CD80, CD86, and PD -L1 in malignant melanoma tissue samples by immunohistochemistry and to investigate the possible relationship between these proteins and the clinicopathological features in this study. Hematoxylin and eosin staining and immunohistochemical staining for CD80, CD86, and PD-L1 were evaluated for clinical data, survival, prognosis, tumor location, malignant melanoma subtypes, tumor size, and prognostic findings. Higher survival rates were observed in patients with lower PD-L1 staining scores in the tumor. The 5-year survival was higher in patients with CD80-positive and CD86-positive biopsies. Mortality was lower in superficial spreading melanoma and Lentigo maligna melanoma types, whereas staining positivity of CD80 and CD86 was higher. Furthermore, a relationship between clinical stage and Breslow thickness ( < 2mm/≥2mm), tumor ulceration, lymph node metastasis, and CD80 and CD86 expression was also identified. Our findings suggest that PD-L1, CD80, and CD86 expression are essential in malignant melanoma and could be used as prognostic markers.

Annular pigmented actinic keratosis mimicking lentigo maligna melanoma in a 75-year-old female: An unusual presentation

Annular pigmented actinic keratosis mimicking lentigo maligna melanoma in a 75-year-old female: An unusual presentation

Trends in three major histological subtypes of cutaneous melanoma in the Netherlands between 1989 and 2016.

Time trend analysis of cutaneous melanoma (CM) mortality in fair skin populations shows both a gradual decrease and/or an increase. To explain these differences, we analyzed long-term time trends in the incidence of the most common histological subtypes of CM: superficial spreading melanoma (SSM), lentigo maligna melanoma (LMM), and nodular melanoma (NM). Using data from the Netherlands Cancer Registry and Statistics Netherlands, the number and rates of cases diagnosed with SSM, LLM, and NM from 1989 to 2016 were analyzed by age, calendar period, and birth cohort of people born in successive periods from 1925 to 1973. Primary CM was diagnosed in 52,000 men and 66,588 women in the study period. The annual age-standardized incidence rate increased three-fold from 14 to 42 per 100,000 person-years. The most common subtype was SSM (50%), followed by LMM (23%) and NM (14%). Age-specific subtype rates showed an upward trend over time for both men and women. Younger birth cohorts had higher rates of SSM and LMM diagnosis than older birth cohorts. This birth cohort pattern was not observed for NM. We observed a strong increase in the melanoma epidemic curves in the light-skinned Dutch population over the last three decades. This increase is explained by younger generations having higher rates of SSM and LMM than older generations.

Lentigo melanoma associated with Leser–Trélat syndrome

LeserTrlat syndrome is characterized by the sudden appearance of a large amount of elements of seborrheic keratosis. The syndrome is associated with the development of malignant tumors of internal organs. The reason for the development of the syndrome is probably the production of cytokines by cells of malignant tumors of internal organs (transforming growth factor alpha (TGF-), epidermal growth factor (EGF), etc.) endogenous mediators that affect the proliferation of keratinocytes and cause rapid growth of seborrheic keratosis. Currently, the question of the paraneoplastic nature of multiple seborrheic keratosis remains open. The article presents the observation of an 82-year-old patient with lentigo-melanoma, who developed multiple elements of seborrheic keratosis within a short time, discusses the question of how in this case it is possible to consider this as a paraneoplastic process. This case is interesting for the atypical clinical picture of seborrheic keratosis and the association with lentigo-melanoma.