Journal Information
Vol. 97. Issue 5.
Pages 660-665 (01 September 2022)
Visits
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Vol. 97. Issue 5.
Pages 660-665 (01 September 2022)
Research Letter
Open Access
Dermoscopic characteristics of congenital melanocytic nevi in a cohort study in southern Brazil
Visits
...
Camila Roos Mariano da Rochaa,
Corresponding author
camilamarianodarocha@gmail.com

Corresponding author.
, Thais Corsetti Grazziotinb, Renan Rangel Bonamigoa,c,d
a Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
b Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
c Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
d Dermatology Service, Irmandade Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, RS, Brazil
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Dear Editor,

Congenital melanocytic nevi (CMN) are benign proliferations of melanocytes present at birth or which appear during the first two years of life.1 They are classically classified according to their largest diameter, as small (less than 1.5 cm), medium (between 1.5‒20 cm), and large or giant (greater than 20 cm).2 Larger lesions are more frequently associated with the development of melanoma and have a higher risk of extracutaneous complications (neurocutaneous melanocytosis). Regarding malignancy, prospective studies have established that the overall incidence of melanomas in CMN is low (1%‒2%). However, this incidence varies greatly according to the phenotype severity.3–5

Digital dermoscopy is a noninvasive test. The knowledge of dermoscopic characteristics is important so that this method can be used for patient diagnosis, follow-up, and management. There are few studies evaluating the evolution of the dermoscopic pattern of these nevi over time and its association with clinical and epidemiological characteristics. There is no standardization regarding the ideal period between assessments.4,6–9 The aim of the present study was to assess the clinical and dermoscopic characteristics of patients with CMN, comparing the dermoscopic findings at two medical consultations.

A retrospective cohort study was carried out to analyze the medical and photographic records obtained with digital videodermoscopy (Fotofinder Systems, GmbH, Bad Birnbach, Germany) of patients with CMN referred to the Dermoscopy Sector of a reference service in southern Brazil between 2016 and 2018. Data were collected on the patients general health status, dermatological anamnesis, the evolution of the congenital lesions, and stored macroscopic and microscopic photographic records. The description of variables and possible associations between clinical and dermoscopic aspects were verified.

The results were presented as central tendency measures (mean and median) and variability (standard deviation and interquartile range), in addition to absolute and relative distribution (n, %). The symmetry of continuous distributions was evaluated using the Kolmogorov-Smirnov test; Pearson's chi-square test (χ2) was used for the bivariate analysis of the qualitative variables.

Dermoscopic data were analyzed by two experienced evaluators and were based on the analysis of patterns classified as reticular (Fig. 1), globular (Fig. 2), homogeneous, reticular-homogeneous, globular homogeneous, reticular-globular, and acral patterns (parallel ridges or furrows, fibrillar, lattice and homogeneous). The evaluation was performed in two ways: a descriptive analysis of dermoscopic data of all lesions (those with only one record and those with follow-up; n = 82) and a comparative analysis of dermoscopic data of lesions that were followed over time. (n = 70). Both authors analyzed all recorded lesions and the final diagnostic definitions were attained by consensus. McNemar’s test was used to compare the data. The present study was approved by the Research Ethics Committee of the institution.

Figure 1.

Brownish macula on dermoscopy showing a typical reticular pattern.

(0.16MB).
Figure 2.

Small brownish papule on dermoscopy showing a typical globular pattern.

(0.18MB).

Eighty-two CMN were observed in 72 patients. Most individuals were phototype III (62.5%), had dark brown/black eyes (67.6%); medium/dark brown hair (38.9%) and 45.1% of the lesions were located on the extremities. Most lesions were small (58.5%; Table 1). The reticular pattern was the predominant dermoscopic pattern (31.7%), with the pigment network being the most common dermoscopic structure (70.7%; Table 2). The comparison between the first and the last clinical and dermoscopic examinations included 70 lesions, with a mean interval between them of 12.49 months and a median of 10 months (1st‒3rd quartile: 8.0‒12.0), with the minimum period between the two assessments being 4 months and a maximum of 21 months. No morphological and structural differences were detected at the follow-up (p > 0.05; Table 3).

Table 1.

Clinical and epidemiological characterization of patients with congenital melanocytic nevi (n = 72).

VariableTotal sample (n = 72)
Sex     
Male  30  41.7 
Female  42  58.3 
Age (years)     
Mean ± standard deviation (range)  27.2 ± 21.9 (1.0–76)
Median (1st‒3rdquartile)  16.0 (10.3–43.7)
Phototype 
II  8.3 
III  45  62.5 
IV  16  22.2 
5.6 
VI  1.4 
Eye color     
Dark brown/black  48  67.6 
Light brown/hazel  13  18.3 
Light green  7.0 
Blue  7.0 
Skin color/ethnicity     
White  63  87.5 
Brown  9.7 
Black  2.8 
Hair color     
Black  22  30.6 
Dark/medium brown  28  38.9 
Light brown  15  20.8 
Blond  9.7 
Sunburns     
Never  33  45.8 
Once or more  39  54.2 
Use of sunscreen     
Never  6.9 
Occasionally  59  81.9 
Always/daily  11.1 
Family history of skin cancer     
No  54  75.0 
Yes  18  25.0 
Number of CMN     
More than one  12.5 
One  63  87.5 
Location of the main CMN     
Head and neck  8.5 
Trunk  33  40.3 
Extremities  37  45.1 
Gluteal region  3.7 
Inguinal region  2.4 
Classification of the main CMN     
Small  48  58.5 
Medium-sized  30  36.6 
Large/Giant  4.9 
Recent modification     
No  65  90.3 
Yes  9.7 
Histopathological evaluation     
No  68  94.4 
Yes  0.6 
Table 2.

Dermoscopic pattern of congenital melanocytic nevi (n = 82).

CharacteristicsLesions assessed only once (n = 82)Lesions with follow-up (n = 70)
BeforeAfter
pb 
Dermoscopic pattern     
Reticular  26  31.7  23  32.9  23  32.9   
Globular  14  17.1  12  17.1  12  17.1  >0.999 
Reticulo-globular  12  14.6  12.9  12.9   
Homogeneous  17  20.7  15  21.4  15  21.4   
Reticular-homogeneous  12  14.6  11  15.7  11  15.7   
Parallel ridge  1.2           
Color         
Light brown  60  73.2  54  77.1  54  77.1  0.815 
Dark brown  62  75.6  54  77.1  53  75.7  0.869 
Blacka  3.7  1.4  1.4  >0.999 
Reda  4.9  4.3  4.3  >0.999 
Bluea          1.4  >0.999 
Whitea  3.7  2.9  2.9  >0.999 
Blue-gray  8.5  8.6  8.6  >0.999 
Color symmetrya     
Yes  77  93.9  65  95.6  65  95.6  >0.999 
No  6.1  4.4  4.4   
Symmetry of structures     
Yes  76  92.7  66  94.3  66  94.3  >0.999 
No  7.3  5.7  5.7   
Pigment network         
Yes  58  70.7  49  70.0  49  70.0  >0.999 
No  24  29.3  21  30.0  21  30.0   
Dots         
Yes  49  59.8  41  58.6  41  58.6  >0.999 
No  33  40.2  29  41.4  29  41.4   
Globules       
Yes  51  62.2  45  64.3  45  64.3  >0.999 
No  31  37.8  25  35.7  25  35.7   
Striae         
No  82  100.0  70  100.0  70  100.0  ‒ 
Irregular striae       
No  82  100.0  70  100.0  70  100.0  ‒ 
Structureless areas       
Yes  11.0  8.6  8.6  >0.999 
No  73  89.0  64  91.4  64  91.4   
Regressiona   
Yes  1.2  1.4  1.4  >0.999 
No  81  98.8  68  98.6  68  98.6   
Hyperchromic macules     
Yes  3.7  2.9  2.9  >0.999 
No  79  96.3  68  97.1  68  97.1   
Pseudocysts       
Yes  6.1  7.1  7.1  >0.999 
No  77  93.9  65  92.9  65  92.9   
Perifollicular hyperpigmentationa   
No  82  100.0  69  100.0  69  100.0  ‒ 
Perifollicular hypopigmentation   
Yes  19  23.2  19  27.1  18  25.7  0.978 
No  63  76.8  51  72.9  52  74.3   
Hypertrichosis       
Yes  19  23.2  15  21.4  14  20.0  >0.999 
No  63  76.8  55  78.6  56  80.0   
Blue-gray veil     
No  82  100.0  70  100.0  70  100.0  ‒ 
Vascular structures     
Yes  1.2  1.4  1.4  >0.999 
No  81  98.8  69  98.6  69  98.6   
Shiny white structuresa       
No  82  100.0  69  100.0  69  100.0  ‒ 
Negative pigment networka     
Yes  4.9  5.8  5.8  >0.999 
No  78  95.1  65  94.2  65  94.2   
a

Missing data – Black color, Red color, blue color, white color, regression, perifollicular hyperpigmentation; shiny white structures, pigment network, atypical vascular pattern (1 [1.6%]); color symmetry, globules (2 [3,2]).

b

McNemar-Bowker Test.

Table 3.

Dermoscopic characteristics and follow-up interval.

CharacteristicsTime of interval - months (n = 70)
Up to 10 months(n = 47)>10 months (n = 23)
BeforeAfterpbBeforeAfterpb
Dermoscopic pattern          ‒      ‒ 
Reticular  15  31.9  15  31.9    34.8  34.8   
Globular  19.1  19.1    13.0  13.0   
Reticulo-globular  10.6  10.6    17.4  17.4   
Homogeneous  17.0  17.0    30.4  30.4   
Reticular-homogeneous  10  21.3  10  21.3    4.3  4.3   
Homogeneous pattern                    >0.999 
Yes  19  40.4  19  40.4  ‒  34.8  39.1   
No  28  59.6  28  59.6    15  65.2  14  60.9   
Color symmetrya          ‒          ‒ 
Yes  44  93.6  43  93.5    23  100.0  22  100.0   
No  6.4  6.5             
Structure symmetry          ‒      ‒ 
Yes  45  95.7  45  95.7    21  91.3  21  91.3   
No  4.3  4.3    8.7  8.7   
Pigment network          ‒          ‒ 
Yes  34  72.3  34  72.3    15  65.2  15  65.2   
No  13  27.7  13  27.7    34.8  34.8   
Dots          ‒          ‒ 
Yes  24  51.1  24  51.1    17  73.9  17  73.9   
No  23  48.9  23  48.9    26.1  26.1   
Globules          ‒          ‒ 
Yes  30  63.8  30  63.8    15  65.2  15  65.2   
No  17  36.2  17  36.2    34.8  34.8   
a

Missing data – Pigment network, Color symmetry, globules (2 [3,2%]).

b

McNemar-Bowker Test.

The lesions of four patients were submitted to histopathological analysis. The indications in these cases were as follows: the presence of a central papule in a medium-sized CMN located on the right shoulder of a 10-year-old patient, the presence of a central papule in a small lesion located on the fifth left toe of a 10-year-old patient, a satellite lesion in a patient with a large CMN located on the lumbar region and a lesion with structure asymmetry and a homogeneous pattern with predominant blue-gray color, located on the left thigh of a 10-year-old patient. All histopathological diagnoses were of compound melanocytic nevi. None of the assessed patients developed melanoma. Of the four patients with large/giant CMN included in the study, three had an indication for imaging examination and two had already undergone nuclear magnetic resonance with normal results.

Some studies have sought to describe specific dermoscopic features of CMN. Light brown globules with a central dot (target globules), target pigment network, focal pigment network thickening, perifollicular/focal hypopigmentation, and target vessels have been described as characteristics present in congenital lesions, although they were not specific. In the case of lesions that must be monitored over time, digital dermoscopy appears as an important tool. There are only a few studies describing the evolution and comparison of the dermoscopic features of these lesions and their correlations with the histopathological diagnoses.10 Regarding the clinical data of patients in the present study, it was observed that small nevi predominated, a result consistent with other published data.8,9 The predominant dermoscopic pattern was the reticular one, regardless of the nevus location, unlike the data found in the literature, which found the globular pattern to be the most common. When comparing the predominant dermoscopic pattern with age, it was observed that the globular pattern was related to patients younger than 12 years, whereas the reticular pattern was related to those over this age, corroborating the data found in the literature.10,11

A recent study found characteristics of atypical nevi present in CMN, such as radiating striae, focal hypopigmentation, atypical globules and blotches, regression, and blue-gray veil. In the present study, the authors did not find striae nor blue-gray veils; the vast majority of globules were typical, and regression was observed in only one lesion.10

In addition to the difficulty in the follow-up of patients, there is difficulty regarding the long follow-up time, necessary for any changes to appear. The present study sought to evaluate the dermoscopic characteristics and their changes during videodermoscopy follow-up and correlate them to biopsy indications and histopathological results. Using descriptive data, the clinical and dermoscopic characteristics of the CMN in the initial evaluation of the patients were demonstrated.

When comparing the images recorded in the initial and final evaluations, it was observed that there were no significant differences in the studied period. One of the limitations is the reduced follow-up time (mean of 12 months) since many of the expected outcomes (clinical and dermoscopic changes that indicate lesion excision, and the infrequent presence of malignancy) generally develop after many years. Another limitation is the diversity of the studied population, including children and adults, considering that lesions tend to be stable in the latter. The relatively small number of patients (72) is also be one of the limiting factors.

The present study obtained results that allow the clinical and dermoscopic characterization of patients with CMN, although studies with a larger sample size and a longer follow-up interval are necessary to demonstrate the real benefit of digital dermoscopy when monitoring these lesions over time.

Financial support

None declared.

Authors’ contributions

Camila Roos Mariano da Rocha: Statistical analysis; approval of the final version of the manuscript; design and planning of the study; drafting and editing of the manuscript; collection, analysis, and interpretation of data; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the literature; critical review of the manuscript.

Thais Corsetti Grazziotin: Design and planning of the study; drafting and editing of the manuscript; collection, analysis, and interpretation of data; effective participation in research orientation; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; approval of the final version of the manuscript.

Renan Rangel Bonamigo: Statistical analysis; design and planning of the study; drafting and editing of the manuscript; collection, analysis, and interpretation of data; effective participation in research orientation; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; approval of the final version of the manuscript.

Conflicts of interest

None declared.

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Study conducted at the Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil.

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Anais Brasileiros de Dermatologia

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