Dermatoscopic features of 67 excised melanocytic lesions in patients at high risk of cutaneous malignant melanoma in a Brazilian hospital

To the Editor: Dermatoscopy enables early diagnosis of melanoma, reducing morbidity and mortality.1Ji-Xu A. Dinnes J. Matin R.N. Total body photography for the diagnosis of cutaneous melanoma in adults: a systematic review and meta-analysis.Br J Dermatol. 2021; 185: 302-312Crossref PubMed Scopus (7) Google Scholar The present study evaluated the dermatoscopic features of pigmented lesions excised between January 2015 and March 2021 from patients at high risk of cutaneous malignant melanoma (CMM) followed by a two-step method in the Hospital das Clinicas, Faculty of Medicine of the University of Sao Paulo, Sao Paulo, Brazil. Dermatoscopic images stored in the FotoFinder® dermoscope were analyzed by 3 specialists independently, blinded to the histopathologic diagnosis. They were asked to assess the presence of predefined dermatoscopic features. For the monitored lesions, data were obtained right before excision, and substantial symmetric or asymmetric enlargement and arising of new structures were also evaluated. Divergent answers were discussed until a consensus. Patients under 18 years old and those with a congenital melanocytic nevus, xeroderma pigmentosum, bullous epidermolysis, ichthyosis, albinos, lesions with low-definition images, or located on the palms, soles, mucosa, and nails were excluded. The lesions were separated by histopathologic diagnosis (melanoma vs nevi) to compare dermatoscopic features. Qualitative variables were represented by absolute and relative frequencies. The Pearson’s chi-square test or Fisher’s exact test was used to evaluate the correlation between variables. Differences were statistically significant when P < .05. A total of 67 pigmented lesions from 26 patients were included (Table I). Twenty lesions were melanomas, with 80% in situ. The invasive melanomas had a maximum Breslow thickness of 0.5 mm. Melanomas showed 35% of negative pigment network, 70% of multiple colors, and 15% of bluish-white veil. Other dermatoscopic features had P > .05.Table IComparative analysis of dermatoscopic features of melanomas versus neviDermatoscopic featuresTotalMelanomaPNoYesN = 67n = 47n = 20n (%)n (%)n (%)Irregular pigment network No18 (26.9)13 (27.7)5 (25.0).822∗Pearson’s chi-square test. Yes49 (73.1)34 (72.3)15 (75.0)Negative pigment network No54 (80.6)41 (87.2)13 (65.0).047†Fisher’s exact test. Yes13 (19.4)6 (12.8)7 (35.0)Irregularly distributed globules/dots at the periphery No34 (50.7)22 (46.8)12 (60.0).323∗Pearson’s chi-square test. Yes33 (49.3)25 (53.2)8 (40.0)Atypical vascular pattern No56 (83.6)42 (89.4)14 (70.0).072†Fisher’s exact test. Yes11 (16.4)5 (10.6)6 (30.0)Regular blotches No56 (83.6)38 (80.9)18 (90.0).484†Fisher’s exact test. Yes11 (16.4)9 (19.1)2 (10.0)Irregular blotches No37 (55.2)29 (61.7)8 (40.0).102∗Pearson’s chi-square test. Yes30 (44.8)18 (38.3)12 (60.0)Multiple colors No35 (52.2)29 (61.7)6 (30.0).017∗Pearson’s chi-square test. Yes32 (47.8)18 (38.3)14 (70.0)Radial streaming No62 (92.5)44 (93.6)18 (90.0).631†Fisher’s exact test. Yes5 (7.5)3 (6.4)2 (10.0)Pseudopods No59 (88.1)41 (87.2)18 (90.0).999†Fisher’s exact test. Yes8 (11.9)6 (12.8)2 (10.0)Peppering No62 (92.5)44 (93.6)18 (90.0).631†Fisher’s exact test. Yes5 (7.5)3 (6.4)2 (10.0)Scar-like depigmentation No49 (73.1)37 (78.7)12 (60.0).114∗Pearson’s chi-square test. Yes18 (26.9)10 (21.3)8 (40.0)Bluish-white veil No64 (95.5)47 (100)17 (85.0).024†Fisher’s exact test. Yes3 (4.5)03 (15.0)∗ Pearson’s chi-square test.† Fisher’s exact test. Open table in a new tab Forty-six lesions had been monitored for a minimal 3-month interval (Table II). Asymmetric enlargement was present in 80% of the melanomas, suggesting a tendency in this group. No statistically significant differences were observed in evolutive features, which may be explained by the fact that most melanomas arise de novo.2Haenssle H.A. Korpas B. Hansen-Hagge C. et al.Selection of patients for long-term surveillance with digital dermoscopy by assessment of melanoma risk factors.Arch Dermatol. 2010; 146: 257-264Crossref PubMed Scopus (71) Google Scholar.Table IIMonitored lesions and evolutive features: melanomas versus neviType of changeTotalMelanomaP∗Fisher’s exact test.NoYesN = 46n = 36n = 10n (%)n (%)n (%)Symmetric enlargement No37 (80.4)28 (77.8)9 (90.0).659 Yes9 (19.6)8 (22.2)1 (10.0)Asymmetric enlargement No22 (47.8)20 (55.6)2 (20.0).074 Yes24 (52.2)16 (44.4)8 (80.0)Arising of new structures No23 (50.0)19 (52.8)4 (40.0).722 Yes23 (50.0)17 (47.2)6 (60.0)∗ Fisher’s exact test. Open table in a new tab Menzies et al3Menzies S.W. Ingvar C. McCarthy W.H. A sensitivity and specificity analysis of the surface microscopy features of invasive melanoma.Melanoma Res. 1996; 6: 55-62Crossref PubMed Scopus (225) Google Scholar also compared dermatoscopic features of melanomas and nevi. Negative pigment network and bluish-white veil were highly specific for melanomas. Multiple colors were significant among melanomas, and a single-color lesion was correlated with no melanomas.3Menzies S.W. Ingvar C. McCarthy W.H. A sensitivity and specificity analysis of the surface microscopy features of invasive melanoma.Melanoma Res. 1996; 6: 55-62Crossref PubMed Scopus (225) Google Scholar A Spanish study with 200 CMMs observed bluish-white veil and negative pigment network mainly in invasive melanomas. The multicomponent pattern (multiple colors and structures) was the most common global dermatoscopic feature.4Ciudad-Blanco C. Avilés-Izquierdo J.A. Lázaro-Ochaita P. Suárez-Fernández R. Dermoscopic findings for the early detection of melanoma: an analysis of 200 cases.Actas Dermosifiliogr. 2014; 105: 683-693Crossref PubMed Google Scholar In our study, 3 lesions presented bluish-white veils, all melanomas, although only 1 was invasive. A negative pigment network was observed in 35% of the melanomas and 50% of the invasive ones. This mismatching is probably explained by the few invasive melanomas in our analysis. A recent review and meta-analyses of total-body photography for the diagnosis of CMM revealed the number needed to excise of 8.6 (range: 2.3-19.6).1Ji-Xu A. Dinnes J. Matin R.N. Total body photography for the diagnosis of cutaneous melanoma in adults: a systematic review and meta-analysis.Br J Dermatol. 2021; 185: 302-312Crossref PubMed Scopus (7) Google Scholar Our study had the number needed to excise of 3.35, showing good clinical decisions assisting high-risk patients. Dermatoscopic features can be decisive to biopsy a melanocytic lesion.2Haenssle H.A. Korpas B. Hansen-Hagge C. et al.Selection of patients for long-term surveillance with digital dermoscopy by assessment of melanoma risk factors.Arch Dermatol. 2010; 146: 257-264Crossref PubMed Scopus (71) Google Scholar In our study, negative pigment network, multiple colors, and bluish-white veil were significantly related to melanomas. Our results are in accordance with the literature and suggest that the melanoma-specific criteria might be the same in the Brazilian population. None disclosed. The authors thank the surgeons and the dermatopathologists of the Department of Dermatology of the Hospital das Clinicas, Faculty of Medicine of the University of Sao Paulo, Sao Paulo, Brazil.