Cases Of Primary Cutaneous Melanoma Research Articles

Proof of concept that melanoma nuclear count compares favourably with the benchmark histological prognostic feature, Breslow thickness.

Breslow thickness (BT) is the most important histological prognostic feature for melanoma prognosis, but it only captures tumour size in one dimension. Adding a further measurement in a different axis has been shown to improve prognostic value. It seems reasonable that further prognostic value could be obtained by estimating the number of invasive melanoma cells using nuclear count. The aim of this study was to show proof of concept that nuclear count has prognostic value independent of BT. Melanoma cell nuclei were labelled with SRY-related HMG-box 10 (SOX10) protein, the sections scanned and StarDist machine-learning algorithm used to count nuclei in 102 cases of primary cutaneous melanoma. Prognostic value was assessed using survival analyses. Nuclear count correlated strongly with T category, BT and calculated tumour area (each P < 0.001), suggesting that it was a valid marker of melanoma burden. Nuclear count was a predictor for overall survival in univariable analysis [hazard ratio (HR) = 2.25, confidence interval (CI) = 1.66-3.06, P < 0.001] and multivariable analysis (HR = 2.60, CI = 1.59-4.24, P < 0.001). BT and ulceration were significant in univariable analyses, but not in multivariable models with nuclear count. Models containing nuclear count showed the best fit. Similar results were seen for melanoma-specific and metastasis-free survival. Nuclear count was able to stratify melanomas within a given T stage. This study demonstrated proof of concept that counting melanoma nuclei may be an improved measure of invasive tumour burden compared to BT. Future studies will need to refine methods of nuclear detection and also to confirm its prognostic value.

The potential impact of dietary choices on melanoma risk: an anti-inflammatory diet

The role of inflammation in the aetiology of cancer is recognized. However, no study yet examined the association between an anti-inflammatory diet and cutaneous melanoma and explored whether it could be modified by genetic variations in cyclooxygenase-2 (COX-2), a key enzyme in inflammation. A case-control study was conducted in the IDI-IRCCS hospital in Rome, Italy with 273 cases of primary cutaneous melanoma and 269 controls frequency matched to cases. Information on socio-demographic and pigmentary characteristics, medical history, sun exposure and dietary habits were collected for all subjects. The − 765G > C polymorphism was identified in DNA extracted from blood samples. An anti-inflammatory diet score was created. Logistic regression models were fitted to obtain odds ratios (ORs) and 95% confidence intervals (CIs). A high anti-inflammatory diet score (≥ 8 anti-inflammatory dietary items) was associated with a decreased risk of cutaneous melanoma (OR: 0.29; 95%CI: 0.17–0.49, Ptrend < 0.0001) after adjusting for sex, age, education, number of common nevi, skin photo-type, solar lentigines and sunburns in childhood. COX-2 -765 G > C polymorphism was not an independent risk factor for cutaneous melanoma. Although interaction between − 765G > C genotypes and anti-inflammatory diet score was not statistically significant (p = 0.25), when stratified by -765 G > C genotypes the effect of the anti-inflammatory diet was slightly more pronounced for participants carrying – 765GG (OR: 0.17; 95%CI: 0.06–0.47, Ptrend < 0.001). Our study findings suggest that adherence to an anti-inflammatory diet is associated with a decreased risk of developing cutaneous melanoma. These results suggest the potential impact of dietary choices on melanoma risk.

Low incidence of BRAF and NRAS mutations in a population with a high incidence of melanoma

Reported rates of BRAF mutation in Irish cutaneous melanoma cohorts are lower than the reported international data. We aimed to assess the mutational status of a cohort of primary cutaneous melanomas and to correlate it with clinical follow-up data.A total of 92 cases of primary cutaneous melanoma diagnosed at a single institution in 2012 were analyzed. Regions containing common mutations in the BRAF, NRAS, KIT, and KRAS genes were investigated by PCR amplification followed by Sanger sequencing. Demographic details, tumor characteristics, and 10-year outcome data were also obtained.Ten cases with BRAF V600E mutations (11.6%) and five (5.49%) NRAS mutations (4 at Q61R, 1 at Q61K) were detected. No statistically significant differences were noted between groups for age, gender, depth of invasion, nodal status, or recurrence status (p ≥ 0.05).These findings suggest that the Irish population has a markedly lower incidence of BRAF and NRAS mutations in melanoma than those reported in other cohorts.

Can angiotropism and lymphovascular invasion refine the current cutaneous melanoma staging system?

Several prognostic factors for primary cutaneous melanoma (PCM) have been identified, and these predict metastasis and survival, to a certain extent. We sought to determine the frequency of angiotropism (AT) and lymphovascular invasion (LVI) in PCM and the relationship between AT, LVI, and other clinicopathological parameters and patient's prognosis. This study included 538 cases of PCM diagnosed between 2003 and 2016. It comprised 246 females and 292 males whose clinicopathological variables were evaluated with respect to LVI and AT using univariate and multivariate analyses. Overall survival (OS) was assessed by Kaplan-Meier (KM) analysis and Cox regression multivariate analysis. AT occurred more frequently than LVI. Ulceration, mitotic rate, and Breslow thickness were found to be highly associated with both LVI and AT (p < 0.01). All LVI+ cases had AT, with a significant positive correlation (p < 0.01). Both AT and LVI predicted lymph node (LN) metastasis (odds ratio [OR] = 1.47, 1.12, respectively). Multivariate analysis showed LN metastasis, Breslow thickness, LVI, and AT as predictors of OS. LVI and AT independently predicted adverse OS by Cox regression analysis (hazard ratio [HR] = 1.66, 1.49, respectively) and with KM survival analysis. AT is a marker for angiotropic extravascular migratory tumor spread (angiotropic EVMM), and LVI is a marker for intra-lymphovascular tumor spread. Both predict poor prognosis. Given its ease of detection, AT could be adopted as a histologpathological feature in the routine assessment of primary cutaneous malignant melanoma cases.

The Importance of Immunohistochemistry in the Evaluation of Tumor Depth of Primary Cutaneous Melanoma.

Primary cutaneous melanoma (PCM) is the most aggressive skin malignancy, with an increasing incidence and significant mortality. Tumoral invasion, expressed as Breslow thickness, is routinely assessed on hematoxylin and eosin (HE), although this stain may sometimes underestimate the tumoral depth. The aim of this study was to compare the efficiency of the immunohistochemical (IHC) markers S-100, SOX10, Melan-A, and HMB-45 with HE for the evaluation of the Breslow thickness and staging of PCM. This retrospective study included 46 cases of PCM diagnosed between 2015 and 2022; for each case, the Breslow thickness using HE, S-100, SOX10, Melan-A, and HMB-45 was measured and the appropriate T category was recorded. The highest values of the Breslow thickness were observed for S-100. However, S-100, SOX10, and Melan-A provided statistically significant higher values of the Breslow thickness compared to HE, but no difference was noted between HMB-45 and HE. S-100 was most frequently involved in increasing the T category (26.1%), the majority of cases being upstaged from T1a to T1b. The IHC markers S-100, SOX10, and Melan-A contributed to better evaluation of the melanoma invasion, especially in thin melanomas, but their impact on staging and consecutive treatment remains to be confirmed by future studies.

Impact of the COVID-19 pandemic on the epidemiological and clinicopathological profile of cases of primary cutaneous melanoma diagnosed at Professor Rubem David Azulay Institute of Dermatology

Impact of the COVID-19 pandemic on the epidemiological and clinicopathological profile of cases of primary cutaneous melanoma diagnosed at Professor Rubem David Azulay Institute of Dermatology

Primary Cutaneous Melanoma in a Tertiary Hospital: A Retrospective Study.

Malignant melanoma, the most aggressive form of skin cancer worldwide is much often talked about in the western world and in Caucasian population as it is seen to be a rare disease in South Asians. This study aims to provide a better assessment on the spectrum of cutaneous melanomas in our context. This was a retrospective, 11-year hospital-based study done in the Department of Pathology, Tribhuvan University Teaching Hospital. The data collected included age, sex, anatomical site, Breslow thickness in millimeter, Clark's level of invasion, presence of ulceration, Tumor infiltrating lymphocytes and melanoma subtypes. The anova test was used to compare the relationship between age and staging, whereas pearson's chi square test was used to determine the relationships of sex and histopathological subtype with staging. Out of total, 44 cases of primary cutaneous melanoma were seen, 23 (52.27%) were males and 21 (47.27%) were females. The mean age was 61.29 year with the majority in the age groups 61-70 and 71-80 comprising 11 cases each (25%). Lower extremity was the most frequent site (23 cases, 52.27 %). The largest group (18 cases) was composed of Nodular melanoma, followed by acral melanoma (17 cases). Nodular melanoma tended to occur at a higher stage than other types. Age and sex showed no correlation with staging. A significant association was found with histopathological type. Primary melanoma is a commonly encountered malignancy. It is commomly appreciated equally among both gender among elderly populations. Nodular melanoma present late and is the commonest variety with lower extremity being the commonest site Keywords: Breslow thickness; clark's level; cutaneous melanoma; nodular melanoma.

The prognostic significance of microsatellites in cutaneous melanoma.

Microscopic satellite metastases are an adverse prognostic feature in primary cutaneous melanoma patients. The prognostic significance of microsatellites, including their number, size and distance from the primary melanoma, using the 8th edition American Joint Committee on Cancer definition, has not previously been evaluated. This study sought to determine the prognostic significance of microsatellites in histopathologically reviewed cases. Eighty-seven cases of primary cutaneous melanoma with the presence of microsatellites documented in the original pathology report and all histopathology slides available were reviewed and the findings were correlated with clinical outcome. Matched control cases were selected for all confirmed microsatellites cases. The presence of microsatellites was confirmed in 69 cases. The microsatellite group had significantly worse prognosis, with 21% 5-year disease-free survival compared with 56% in the control group (p < 0.001). The 5-year melanoma-specific survival was 53% in the microsatellites group and 73% in the control group (p = 0.004). Increasing distance (mm) of the microsatellite from the primary melanoma was found to adversely influence disease-free survival (HR = 1.24, 95% CI: 1.13-1.36, p < 0.001), overall survival (HR = 1.26 95%CI: 1.13-1.40, p < 0.001), and melanoma-specific survival (HR = 1.27 95% CI: 1.11-1.45, p < 0.001). Number and size of microsatellites were not significant prognostic factors. The presence of microsatellites was the only factor that proved to be an independent predictor of sentinel node positivity in multivariate analysis (OR 4.64; 95% CI 1.66-12.95; p = 0.003). Microsatellites were significantly associated with more loco-regional recurrences (p < 0.001) but not distant metastases (p = 0.821). Melanomas with microsatellites as defined by the 8th edition American Joint Committee on Cancer staging system are thus aggressive tumors, associated with significantly worse disease-free survival, overall survival and melanoma-specific survival. The presence of microsatellites is also associated with sentinel node-positivity and local and in-transit recurrence. Increasing distance of the microsatellite from the primary tumor is an independent adverse prognostic factor that warrants further evaluation.

Is the survival rate for acral melanoma actually worse than other cutaneous melanomas?

It is still not clear whether the survival rate for acral melanoma (AM) is better or worse than that of cutaneous melanoma developed at other sites. We sought to evaluate the difference in survival depending on the primary tumor site of cutaneous melanoma. We retrospectively reviewed primary cutaneous melanoma cases diagnosed at Samsung Medical Center, a tertiary institution in Korea, from January 1995 to July 2017. The cohort consisted of 642 patients, with 389 non-acral cutaneous melanoma (NACM) patients and 253 AM patients. The AM patients had a higher percentage of stage 0 diagnoses than the NACM patients (31.6% vs 6.9%, respectively). The factors associated with overall survival were primary tumor site, sex, age, American Joint Committee on Cancer stage, surgery and medical treatment (P<0.05). Non-acral sites showed worse survival in multivariable analysis (hazard ratio [HR], 1.457; 95% confidence interval [CI], 1.051-2.020; P=0.0240). Among the NACM, melanomas on the trunk were associated with a higher risk of mortality compared with AM (HR, 1.883; 95% CI, 1.142-3.107; P=0.0131). Acral melanoma was associated with a better prognosis than non-acral melanoma, specifically when located on the trunk, in Korean patients.

The anatomic distribution of cutaneous melanoma: A detailed study of 5141 lesions.

There is evidence that cutaneous melanomas at different anatomic sites present with distinctive clinicopathologic features. We examined the anatomic distribution of cutaneous melanoma and its variation by patient characteristics, subtype and Breslow thickness, using high-resolution anatomic site data. A cross-sectional study was performed of all primary cutaneous melanoma cases managed at a tertiary referral centre, analysing prospectively collected clinical data across 50 anatomic subsites. The study included 5141 in situ or invasive melanomas; most were invasive (76.2%), and the median Breslow thickness of invasive lesions was 1.0mm. Superficial spreading (57.2%), lentigo maligna (20.8%) and nodular (12.2%) were the most common histopathological subtypes. Sun-exposed sites such as the female nose and cheek, the male ear, as well as the upper back in both sexes had the highest incidence of melanoma per unit area. When compared to the posterior forearm, the scalp, ear, preauricular, perioral, subungual and plantar sites had thicker invasive melanomas (each P<0.05). The peri-auricular, ear and cheek had the highest incidence of nodular melanoma per unit area. There were subtype-, age- and sex-specific differences in melanoma anatomic distribution. Melanoma most commonly arises in sun-exposed facial areas, as well as the upper back. Increased thickness is found for melanoma in acral and many head and neck sites. Nodular melanoma is more likely to occur in head and neck sites including the peri-auricular area, ear and cheek. Clinicians should carefully assess these sites during skin examinations.

A case of primary cutaneous melanoma with hepatic and lymphatic metastases

A case of primary cutaneous melanoma with hepatic and lymphatic metastases

Pathological review of primary cutaneous malignant melanoma by a specialist skin cancer multidisciplinary team improves patient care in the UK

AimsThe National Institute for Health and Care Excellence advocated the development of specialist skin cancer multidisciplinary teams (SSMDTs) for the management of higher risk invasive skin cancers in the UK....

Differences in the diagnosis of primary cutaneous melanoma in the public and private healthcare systems in Joinville, Santa Catarina State, Brazil

Background:Cutaneous melanoma accounts for up to 80% of deaths caused by skin cancer. Diagnostic suspicion and access to medical care and early intervention in suspected cases is vital to the patient’s prognosis. Objectives:To compare demographic and histopathological characteristics of primary cutaneous melanoma diagnosed in the public healthcare system (Sistema Único de Saúde SUS) and the private system in Joinville, Santa Catarina State, Brazil. Methods:This cross-sectional retrospective study analyzed primary cutaneous melanoma cases recorded from 2003 to 2014 in the resident population of Joinville. Ethical approval was obtained from the local Research Ethics Committee. Results:893 cases of primary cutaneous melanoma were identified. Patients in the private system were mostly younger, while there were more elderly patients in the public healthcare system (p <0.001). There was no statistically significant association between type of care (public/private) and gender or presence of multiple primary cutaneous melanomas. Histological diagnosis of superficial spreading melanoma was more common in patients treated in private healthcare, while nodular melanoma was more frequent in patients in the public healthcare system (p <0.001). Mean Breslow depth in patients treated in private healthcare was 1.35mm, compared to 2.72mm in the public system (p <0.001). Study limitations:This was a retrospective study using secondary databases. Conclusions:thin cutaneous melanoma (in situ cutaneous melanoma and Breslow T1) showed the strongest association with the private healthcare system, while thick cutaneous melanoma was more frequent in the public system (Breslow category T3 and T4) (p <0.001).

Mitotic rate correlates with sentinel lymph node status and outcome in cutaneous melanoma greater than 1 millimeter in thickness: A multi-institutional study of 1524 cases

The 7th edition of the TNM American Joint Committee on Cancer classification incorporates mitotic rate (MR) only for primary cutaneous melanoma (PCM) with Breslow thickness (BT) ≤1mm. To investigate whether and to what extent MR is able to predict sentinel lymph node (SLN) status and clinical outcome of PCM patients with BT >1mm. The study included consecutive patients with PCM. Logistic regression and Cox regression model were used to analyze the impact of MR on SLN status, disease-free survival (DFS), and overall survival. From 1998 to 2015, 1524 PCM (median age 57.8years) cases were diagnosed with a BT >1mm in six centers of the Italian Melanoma Intergroup. Median follow-up was 5.0years. By multivariate analysis, MR was associated with SLN positivity (odds ratio 1.98, 95% confidence interval [CI] 1.12-3.50, P=.018). After adjusting for BT, ulceration, age, sex, and SLN status, MR correlated with a poor DFS (hazard ratio 1.52, 95% CI 1.18-1.97, P=.002) and overall survival (hazard ratio 1.63, 95% CI 1.17-2.29, P=.004). Retrospective analysis. MR is an independent prognostic factor for PCM patients with BT >1mm. Incorporating this tissue biomarker could provide a better stratification of patients entering clinical trials in the adjuvant setting.

Can ultraviolet radiation act as a survival enhancer for cutaneous melanoma?

Some studies have suggested that sun exposure plays a protective role in melanoma survival. This created a paradox as the known carcinogen can act as a cancer promoter and also as a survival enhancer. The aim of this study was to investigate the effect of sun exposure on melanoma mortality using both ambient sun exposure and individual data. A 10-year cohort study was carried out on primary cutaneous melanoma cases (n=972). Residential data were coupled with levels of ultraviolet radiation (UV) to provide a measure of individual exposure. Demographic, histological and clinical data were obtained for all participants. In a subsample, information on pigmentary characteristics, diet, medical history, phenotype and self-reported sun exposure was also collected. Survival analysis and Cox proportional hazards models were used to examine associations. No protective effect was found for UVB or individual sun exposure variables on melanoma mortality. However, an increased risk of mortality was found among patients with cutaneous melanoma located on the lower limbs and in the highest decile of UVB exposure (≥3.298 J/cm2) after controlling for sex, age and Breslow thickness (relative risk: 4.78; 95% confidence interval: 1.30–17.5). The increased risk of mortality for the highest decile of UVB was also confirmed in the subsample after controlling for sex, age, education, use of sun lamps, pigmentary characteristics and diet. The results of the study suggested no protective effect of sun exposure for melanoma mortality and showed that high sun exposure increases the risk of melanoma mortality among patients with melanomas located on the lower limbs.

Analysis of the Clinical and Histopathological Patterns of 100 Consecutive Cases of Primary Cutaneous Melanoma and Correlation with Staging.

BackgroundThis study analyzed 100 consecutive patients with primary cutaneous melanoma over the course of 13 years to determine whether epidemiological differences correspond to different stages of the disease. We also investigated whether epidemiological characteristics affected the survival rate. Our results were compared with those of selected descriptive studies of melanoma in other East Asian populations, in order to determine whether cutaneous melanoma patterns are similar in East Asian populations.MethodsThe patients' medical records were reviewed retrospectively, and we analyzed the relationship of epidemiological characteristics to staging and survival rate. Additionally, papers from Hong Kong and Japan describing these phenomena in East Asian populations were subjected to a statistical comparison.ResultsThe ratio of males to females was 1:1.8, and the foot was the most frequent tumor site (49%). Acral lentiginous melanoma occurred most frequently (55%). Nodular melanoma was associated with a higher stage. Stage III-IV tumors with Clark levels of IV-V were significantly associated with a low survival rate. A statistical analysis of comparable papers reported in Hong Kong and Japan showed similar results with regard to age, tumor location, and histopathological subtypes.ConclusionsThis study provides the first full epidemiological description of 100 consecutive cases of primary cutaneous melanoma in Korea, with results similar to those observed in other East Asian populations. Corresponding to previous findings, nodular melanoma tended to occur at a higher stage than other types, and tumors with high Clark levels and high stages showed a lower survival rate.

Clinicopathological characteristics and mutation profiling in primary cutaneous melanoma.

The incidence of mutations in malignant melanoma varies remarkably according to the subtype of melanoma, and this in itself is affected by racial and geographical factors. Studies screening melanoma case series for different types of mutations are relatively rare. The authors analyzed the frequency of various somatic point mutations of 10 genes in 106 primary cutaneous melanoma cases. The mutations (BRAF, NRAS, KIT, CDKN2A, KRAS, HRAS, PIK3CA, STK11, GNAQ, CTNNB1) were evaluated with real-time PCR-based PCR-Array through allele-specific amplification, and the results were correlated with various clinicopathological characteristics. Mutations were found in 64.2% of the melanomas overall. BRAF (42.5%), NRAS (15.1%), and CDKN2A (13.2%) were the 3 most common mutations. BRAF and NRAS mutations were more frequent in nodular and superficial spreading melanomas (P < 0.001). Associations with BRAF mutation were as follows: male gender [odds ratio (OR) = 2.4], younger age (OR = 2.7), superficial spreading (OR = 15.6) and nodular melanoma (OR = 9.5), trunk localization (OR = 6.3), and intermittent sun exposure (OR = 4.6). A considerable percentage of V600K (44.4%) mutations were found among the BRAF mutations, whereas KIT mutations (3.8%) were less frequent. Multiple mutations were detected in 13.2% of the melanomas. The most common co-occurrences were in the BRAF, NRAS, and CDKN2A genes. The authors analyzed 10 somatic mutations in the main subtypes of primary cutaneous melanomas from the western region of Turkey. Mutations were found in 64.2% of the melanomas overall. The most common mutations were in the BRAF and NRAS genes. In addition to other less common mutations, a notable number of multiple mutations were encountered. The multiplicity and concurrence of mutations in this study may provide further study areas for personalized targeted therapy.

Clinical and Pathological Features of Melanoma in Europeans Living on the Western Costa del Sol in Southern Spain

ObjectiveTo compare clinical and pathological features of melanoma in Spanish patients with those of patients from Central or Northern Europe living in the health district of Costa del Sol Occidental in southern Spain. MethodsWe conducted a descriptive cross-sectional study of all cases of primary cutaneous melanoma histologically confirmed between 2005 and 2011 in the health care district covered by Hospital Costa del Sol in Marbella. We analyzed clinical and pathological features and performed a descriptive analysis of the 2 populations, in addition to univariate analysis with place of birth (Spain vs Central or Northern Europe) as the independent variable. ResultsCompared with Spaniards, patients from Central or Northern Europe were 10 years older at the time of melanoma diagnosis (66.2 vs 56.2 years, P<.001), had lighter skin (types I or II) (90.3% vs 67.1%, P<.001), and greater recreational sun exposure (93.7% vs 66.2%, P<.001). In addition, multiple melanomas (17.6% vs 4.4%, P=.001), nonmelanoma skin cancer (47.2% vs 15.7%, P<.001), and a family history of melanoma (9.5% vs 2.3%, P=.01) were more common in these patients. Central and Northern Europeans also had a higher overall frequency of melanoma on the trunk (46.3% vs 38.7%) and melanoma in situ (54.7% vs 41.8%, P=.03). ConclusionDifferences in melanoma presentation between Spanish patients and patients from Central or Northern Europe appear to be linked to phenotypic and lifestyle factors. A better understanding of these differences will help to tailor melanoma prevention and follow-up programs for multicultural populations, such as those on Spain's Costa del Sol.

Características clínico patológicas del melanoma en residentes europeos de la Costa del Sol occidental

ObjectiveTo compare clinical and pathological features of melanoma in Spanish patients with those of patients from Central or Northern Europe living in the health district of Costa del Sol Occidental in southern Spain. MethodsWe conducted a descriptive cross-sectional study of all cases of primary cutaneous melanoma histologically confirmed between 2005 and 2011 in the health care district covered by Hospital Costa del Sol in Marbella. We analyzed clinical and pathological features and performed a descriptive analysis of the 2 populations, in addition to univariate analysis with place of birth (Spain vs Central or Northern Europe) as the independent variable. ResultsCompared with Spaniards, patients from Central or Northern Europe were 10 years older at the time of melanoma diagnosis (66.2 vs 56.2 years, P<.001), had lighter skin (types I or II) (90.3% vs 67.1%, P<.001), and greater recreational sun exposure (93.7% vs 66.2%, P<.001). In addition, multiple melanomas (17.6% vs 4.4%, P=.001), nonmelanoma skin cancer (47.2% vs 15.7%, P<.001), and a family history of melanoma (9.5% vs 2.3%, P=.01) were more common in these patients. Central and Northern Europeans also had a higher overall frequency of melanoma on the trunk (46.3% vs 38.7%) and melanoma in situ (54.7% vs 41.8%, P=.03). ConclusionDifferences in melanoma presentation between Spanish patients and patients from Central or Northern Europe appear to be linked to phenotypic and lifestyle factors. A better understanding of these differences will help to tailor melanoma prevention and follow-up programs for multicultural populations, such as those on Spain's Costa del Sol.

Role of obesity on the thickness of primary cutaneous melanoma.

Thick primary cutaneous melanoma (PCM) is associated with older age, male sex, being single, a low educational level, self-detection and general practice detection, nodular melanoma (NM) and acral lentiginous melanoma (ALM) types; and are found in the head-neck and lower limb locations. Obesity plays a direct role on melanoma tumour growth, as it has been shown in animal models, but its role in the thickness of PCM remains unknown. We investigated the impact of obesity on the thickness of invasive PCM. A cross-sectional study was performed in a prospective cohort for which we collected several clinical and histological data already known to be associated with thick PCM and the Body Mass Index from new cases of invasive PCM which were referred to the dermatology department in Valence. Four hundred and twenty-seven patients were studied. In an univariate analysis, thick PCM was associated with low educational level, obesity, identification by the patient or the general practitioner (GP), location on the cephalic extremity, in a non-visible area of the body, the NM and ALM type, and an ulceration. In a multivariate analysis, NM, ulceration, topography of the melanoma and identification of the melanoma by the patient or GP were significantly associated with thick melanoma. When including only clinical features in the model, low educational level, mode of melanoma identification and obesity were significantly associated with a risk of thick melanoma. Obesity is a clinical independent risk factor of thick PCM. For health policies, governments should pay greater attention to detect melanoma in obese patients. Our results encourage the basic research on tumoural growth mechanisms due to obesity in melanoma.