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A comparative study of dermoscopic features and monitoring of congenital and acquired nevi of the nail apparatus in pediatric patients

Published:February 20, 2020DOI:https://doi.org/10.1016/j.jaad.2020.02.042
      To the Editor: A conservative approach for melanonychia in children is generally recommended because the vast majority are benign; however, the occasional presence of melanoma-like features in pediatric nevus of the nail apparatus (NNA) can complicate management.
      • Ohn J.
      • Choe Y.S.
      • Mun J.H.
      Dermoscopic features of nail matrix nevus (NMN) in adults and children: a comparative analysis.
      In addition, few data have been reported previously.
      • Lazaridou E.
      • Giannopoulou C.
      • Fotiadou C.
      • Demiri E.
      • Ioannides D.
      Congenital nevus of the nail apparatus—diagnostic approach of a case through dermoscopy.
      We describe and compare clinical and dermoscopic features of congenital and acquired NNA in 32 Colombian children who presented with melanonychia between 2008 and 2018. Inclusion criteria were age <15 years and a clinical and dermoscopic diagnosis of congenital or acquired NNA. Congenital NNA (including late onset) was defined as brown melanonychia appearing before 3 years of age.
      Clinical and dermoscopic features of pediatric NNA are presented in Table I. Compared with acquired NNA (n = 13), congenital NNA (n = 19) were found to be wider (mean, 4.6 ± 2.9 mm vs 2.5 ± 1.6 mm; P = .025) and more likely to have irregular bands (47.4% vs 7.7%; P = .020) and a pseudo-Hutchinson sign (84.2% vs 46.2%; P = 29). Periungual pigmentation (Hutchinson sign) was found only in congenital NNA (31.6% vs 0%; P = .030), whereas a triangular sign (wider pigmentation proximally) was observed in 21.9% of all cases, without a significant difference between groups.
      Table IComparison of clinical and dermoscopic features of melanonychia due to congenital and acquired nevi of the nail apparatus
      Variables
      Values are expressed as the number (%) for categorical data and as the mean ± SD for continuous data.
      Congenital neviAcquired neviTotalP value
      Fisher exact test.
      Patients19 (59.4)13 (40.6)32 (100)
      Clinical features
       Age of onset, y
      Applicable to 6 patients with periungual pigmentation.
      1.4 ± 1.27.3 ± 3.83.8 ± 3.9<.001
      Analysis of variance test.
       Sex
      Female12 (63.2)7 (53.8)19 (59.4).435
      Male7 (36.8)6 (46.2)13 (40.6)
       Location
      Hand15 (78.9)9 (69.2)24 (75).413
      Foot4 (21.1)4 (30.8)8 (25)
       Digit
      19 (47.4)8 (61.5)17 (53.1).667
      25 (26.3)4 (30.8)9 (28.1)
      33 (15.8)03 (9.4)
      41 (5.3)1 (7.7)2 (6.3)
      51 (5.3)01 (3.1)
       Fitzpatrick phototype
      II3 (15.8)1 (7.7)4 (12.5).89
      III9 (47.4)7 (53.8)16 (50)
      IV8 (36.8)5 (38.5)12 (37.5)
       Band width of the melanonychia, mm
      Applicable to 6 patients with periungual pigmentation.
      4.6 ± 2.92.5 ± 1.63.7 ± 2.6.025
      Analysis of variance test.
      Dermoscopic features
       Dominant color of bands
      Light brown8 (42.1)6 (46.2)14 (43.8).271
      Dark brown11 (57.9)5 (38.5)16 (50)
      Black02 (15.4)2 (6.3)
       Triangular sign
      No15 (78.9)10 (76.9)25 (78.1).611
      Yes4 (21.1)3 (23.1)7 (21.9)
       Number of colors present
      14 (21.1)7 (53.8)11 (34.4).189
      212 (63.2)5 (38.5)17 (53.1)
      33 (15.8)1 (7.7)4 (12.5)
       Pattern of bands
      Irregular9 (47.4)1 (7.7)10 (31.3).02
      Regular10 (52.6)12 (92.3)22 (68.8)
       Dark dots and globules
      No17 (89.5)11 (84.6)28 (87.5).542
      Yes2 (10.5)2 (15.4)4 (12.5)
       Periungual pigmentation
      No13 (68.4)13 (100)26 (81.3).03
      Yes6 (31.6)06 (18.8)
       Pseudo-Hutchinson's sign
      No3 (15.8)7 (53.8)10 (31.3).029
      Yes16 (84.2)6 (46.2)22 (68.8)
       Periungual pigmentation
      Applicable to 6 patients with periungual pigmentation.
      Fibrillar4 (66.7)04 (66.7).146
      Peas in a pod1 (16.7)01 (16.7)
      Undetermined1 (16.7)01 (16.7)
      Values are expressed as the number (%) for categorical data and as the mean ± SD for continuous data.
      Fisher exact test.
      Applicable to 6 patients with periungual pigmentation.
      § Analysis of variance test.
      The Cohen κ showed moderate to good agreement between 2 observers (F.P. and C.M.) for most dermoscopic variables. In the 16 patients monitored over time, with mean follow-up of 13.2 ± 22.2 months, increased width and new structures with dynamic changes were observed (Fig 1). Biopsy specimens in 2 patients confirmed the diagnosis of melanocytic nevus of the nail matrix.
      Figure thumbnail gr1
      Fig 1Congenital nevus of the nail apparatus showing broadening of the band of melanonychia, new bands appearing, and new colors. A biopsy confirmed the diagnosis of melanocytic nevus of the nail matrix.
      Previous reports have shown a benign dermoscopic acral pattern for periungual pigmentation in congenital melanonychia.
      • Lazaridou E.
      • Giannopoulou C.
      • Fotiadou C.
      • Demiri E.
      • Ioannides D.
      Congenital nevus of the nail apparatus—diagnostic approach of a case through dermoscopy.
      ,
      • Agusti-Mejias A.
      • Messeguer F.
      • Febrer I.
      • Alegre V.
      Congenital subungual and periungual melanocytic nevus.
      In other studies, Hutchinson sign and other melanoma-like features were observed in pediatric NNA.
      • Ohn J.
      • Choe Y.S.
      • Mun J.H.
      Dermoscopic features of nail matrix nevus (NMN) in adults and children: a comparative analysis.
      ,
      • Lee J.H.
      • Lim Y.
      • Park J.H.
      • et al.
      Clinicopathologic features of 28 cases of nail matrix nevi (NMNs) in Asians: comparison between children and adults.
      Although this is a retrospective analysis with a small sample size and only 2 cases confirmed by pathology, we have found significant differences between congenital and acquired NNA in children, with substantial changes during follow-up. As dynamic changes in melanocytic nevi at other anatomic sites are often observed during childhood,
      • Scope A.
      • Marchetti M.A.
      • Marghoob A.A.
      • et al.
      The study of nevi in children: principles learned and implications for melanoma diagnosis.
      evolution of pediatric NNA over time is not surprising.
      In conclusion, congenital NNA is more likely than acquired NNA to present with melanoma-like dermoscopic features in pediatric patients. The diagnostic approach should include a thorough clinical history and careful examination including dermoscopy. Follow-up with digital dermoscopy can help to avoid unnecessary biopsies that may lead to emotional distress and nail dystrophy. A biopsy should be performed in uncertain cases with concerning features and evolution. However, specific criteria for pediatric melanoma of the nail apparatus have not been defined. More research is needed to identify signs of high-risk lesions and the significance of changes seen in follow-up.
      We acknowledge all Colombian dermatologists that refer patients for dermoscopy and follow-up to our center, for without your support and contributions, this work could not be possible. We acknowledge Luis M. Franco, MD, for advisement and style correction, and nurse Diana Sanin for her contributions in recording of some data and the search for several images.

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        Dermoscopic features of nail matrix nevus (NMN) in adults and children: a comparative analysis.
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