Longitudinal Melanonychia: Differences in Etiology Are Associated with Patient Age at Diagnosis

Abstract

Background: Longitudinal melanonychia (LM) may occur as a result of nail apparatus melanoma. Knowledge of etiology plays an important role in the management of LM. Objectives: The study is aimed to compare the diagnosis of LM in different age groups. Methods: We collected 63 cases (45 adults and 18 children) with LM who underwent nail matrix biopsy or excision in a 21-year cohort and assessed their clinicopathological features. Results: Melanomas in adults and children were 40% and none, while nevi accounted for 15.6% in adults and 94.4% in children. There was a statistically significant difference between the average age at diagnosis for melanoma (54.5 ± 13.3 years) and nevus (15.2 ± 18.5 years). Logistic regression related the occurrence of melanoma to older ages with a relative risk of 1.2 compared to nevus, but no cutoffs between age groups could be defined between LM-associated nevus and melanoma. Conclusion: The adult group has a significantly higher risk of melanoma, while children with LM show mostly nonmelanoma etiologies. Tissue proof is more warranted in adult cases, and it is needed in selected cases of children with LM.

Nail matrix naevi in children: a prospective study

“…In our study, almost all children with NMN had Fitzpatrick III-IV skin type, consistent with the rarity of NMN in very fairskinned individuals. Fingernails were primarily involved a finding that has been observed by other investigators, 4,5 with a predilection for the thumb.…”

“…4 Features that are alarming in adults, such as Hutchinson sign, variation of the colour of the band, a triangular shape, globules and nail dystrophy, are commonly observed in children. [3][4][5][6] Hutchinson sign was detected in seven cases in our series and we identified triangular shape ( Fig. 1b) of the band in two cases but no case of nail dystrophy.…”

“…Previous investigators reported suspicious and worrisome findings of NMN in a greater percentage of children, probably because they presented series that prompted a biopsy. 2,3,[5][6][7] Interestingly, in our study in 2-year follow-up we observed more regular and less disrupted lines in 4/5 children and in 7/16 cases a reduced or loss of pigment. There are no much data about the progression of NMN in children that have not been excised.…”

Melanonychia striata: clarifying behind the Black Curtain. A review on clinical evaluation and management of the 21st century

“…Melanonychia striata may result from melanocytic activation or melanocytic hyperplasia (Tables and ) . In most of the cases, melanonychia striata results from melanocytic activation in the nail matrix (an increase in activity of melanocytes with the subsequent increased synthesis of melanin in the nail matrix and subsequent deposition of melanin in the nail plate without a concurrent increase in the number of melanocytes) .…”

“…In patients with any such atypical or concerning features, a nail matrix biopsy for the histologic examination should be considered. The threshold biopsy should be low for white‐skinned individuals . Histopathological examination of the nail matrix biopsy is the gold standard to determine the cause of the melanonychia.…”