Melanocytic lesions ≤ 6mm: Prospective series of 481 melanocytic trunk and limb lesions in Brazil

Abstract

Early diagnosis when melanoma is still small and thin is essential for improving mortality and morbidity. However, the diagnosis of small size melanoma might be particularly difficult, not only clinically but also dermoscopically. This study aimed to define clinical and dermatoscopic parameters in the diagnosis of suspicious pigmented cutaneous lesions with a diameter of ≤ 6mm and determine the sensitivity, specificity, positive and negative predictive values as well as the accuracy of each clinical and dermatoscopic criterion. This is a transversal, descriptive and analytical study of dermatoscopic analysis with the gold standard being the pathologic examination obtained from the excisional biopsy of suspicious melanocytic lesions with a diameter of ≤ 6mm. Trunk and limb lesion data from a public health service and a private clinic were prospectively collected from 2011 to 2017 by a unique observer. In total, 481 melanocytic lesions were included, with 73.8% being ≤ 4mm in diameter. Overall, 123 were diagnosed as melanoma, 56.0% in situ and 22.0% as thin melanomas (Breslow index 0.1 to 1.0mm). Melanoma presented symmetry in 53.7% of cases, regular borders in 54.5% and a single color in 60.2%. Regarding evolution, 13.8% of melanomas versus 10.9% of benign lesions (p = 0.116) were new by comparing photos from baseline with photos from the follow-up. The majority of melanomas (65%) were found on the limbs compared to 37.2% of the benign lesions at this location (p<0.001). A multiple logistic regression model adjusted for age, gender and location was created. The independent variables associated with the diagnosis of melanoma ≤ 6mm, adjusted for age, gender and location, were: streaks (adjusted Odds Ratio [aOR] 2.5; 95% CI 1.3–4.7; p = 0.006), and the presence of a structureless area (aOR 2.2, 95% CI 1.2–4.0, p = 0.011). Conversely, a symmetric typical pigment network was a protection variable (aOR 0.4, 95% 0.7–0.9, p = 0.040). In conclusion, dermatoscopic criteria have been identified which help to diagnose cases of small size melanoma. These include streaks and structureless areas that can be taken, particularly in consideration for the diagnosis of this subset of small difficult melanomas.

Dermoscopy of Small Diameter Melanomas with the Diagnostic Feasibility of Selected Algorithms—A Clinical Retrospective Multicenter Study

“…The first publication describing the dermoscopic diagnosis of microM was carried out by Bono et al, 1999 [ 5 ]. To date, seventeen other studies have been published showing significant differences in the sizes of samples (8–123 microM; median 27.5) and methodologies [ 2 , 3 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] ( Table S1 ).…”

“…Five studies were conducted without the comparator group [ 8 , 9 , 12 , 16 , 19 ]. Studies conducted by Carli et al, 2003, Friedman et al, 2008, Abbasi et al, 2008, Pupelli et al, 2013, Drugge et al, 2018 and Campos-do-Carmo et al, 2021 chose melanocytic lesions as the comparator group [ 7 , 10 , 11 , 13 , 18 , 20 ]. Two of them analyzed microM with melanocytic nevi of the same diameter [ 13 , 20 ].…”

“…Studies conducted by Carli et al, 2003, Friedman et al, 2008, Abbasi et al, 2008, Pupelli et al, 2013, Drugge et al, 2018 and Campos-do-Carmo et al, 2021 chose melanocytic lesions as the comparator group [ 7 , 10 , 11 , 13 , 18 , 20 ]. Two of them analyzed microM with melanocytic nevi of the same diameter [ 13 , 20 ]. The remaining studies chose different types of melanomas as the comparator group [ 3 , 6 , 14 , 15 , 17 ].…”

“…The diagnostic feasibility of dermoscopic algorithms in small-diameter melanomas was assessed by Bono et al, 2006 (Menzies method sensitivity 83%; specificity 69%), Seidenari et al, 2014 (7-point checklist and ABCD rule of Stoltz; data of sensitivity or specificity were not provided) Dika et al, 2017 (diagnostic sensitivity of pattern analysis 64.05%; 7-point checklist 61.08%; Menzies method 57.30%; ABCD rule of Stoltz 42.70%.) and Campos-do-Carmo et al, 2021 (modified ABC-point list algorithm sensitivity 61.8%; specificity 48.3%) [ 9 , 14 , 17 , 20 ]. Six studies (Bono et al, 1999, Carli et al, 2003, Bono et al, 2004 and 2006, Abbasi et al, 2008 and Campos-do-Carmo et al, 2021) compared the dermoscopic examination with the naked eye examination based on the clinical ABCDE rule with a wide range of sensitivity (36.6–83%) and specificity (38–91%) [ 5 , 7 , 8 , 9 , 11 , 20 ].…”

“…and Campos-do-Carmo et al, 2021 (modified ABC-point list algorithm sensitivity 61.8%; specificity 48.3%) [ 9 , 14 , 17 , 20 ]. Six studies (Bono et al, 1999, Carli et al, 2003, Bono et al, 2004 and 2006, Abbasi et al, 2008 and Campos-do-Carmo et al, 2021) compared the dermoscopic examination with the naked eye examination based on the clinical ABCDE rule with a wide range of sensitivity (36.6–83%) and specificity (38–91%) [ 5 , 7 , 8 , 9 , 11 , 20 ].…”