# Longitudinal Melanonychia in Children: Clinical and Histopathologic Features and Management with Literature Update

## TL;DR

Longitudinal melanonychia in children is usually benign and can be managed with careful monitoring rather than surgery.

## Contribution

The paper provides updated clinical and histopathologic insights into pediatric longitudinal melanonychia and advocates for conservative management strategies.

## Key findings

- Most pediatric longitudinal melanonychia cases are caused by benign nail matrix lesions.
- Spontaneous regression of pigmented bands is common in children.
- Conservative management with follow-up is recommended over immediate biopsy or surgery.

## Abstract

Longitudinal melanonychia, defined as a pigmented band along the nail plate, is uncommon in children and is most often caused by benign melanocytic lesions of the nail matrix, particularly nevi. However, these lesions frequently display clinical, dermoscopic, and histopathologic features that may resemble melanoma in adults, creating diagnostic uncertainty. Nail unit melanoma in children is extremely rare, and its diagnosis remains controversial in the literature. Because many warning signs used in adults are not reliable in pediatric patients, management strategies must differ. Most cases can be safely managed with careful clinical and dermoscopic follow-up rather than immediate biopsy. Surgical intervention should be reserved for lesions showing significant clinical concern, as nail procedures in children are technically challenging and may lead to permanent nail dystrophy. A cautious and conservative approach, ideally involving clinicians and dermatopathologists experienced in nail disorders, is therefore recommended when evaluating longitudinal melanonychia in children.

Longitudinal melanonychia (LM) results from the deposition of pigment in the nail plate due to increased melanocytic activity within the nail matrix. Recent publications on this topic have helped clarify the main clinical, histological, and evolutionary characteristics of pediatric LM and provide guidance for its appropriate management. In this review, we will examine the literature on the subject. LM is far less common in children than in adults and is most often caused by benign nail matrix lesions. Pediatric LM has specific clinical and histopathologic features, and many of the clinical warning signs used in adults are not applicable to children. Pediatric lesions may show atypical cytologic and even architectural features yet still follow a benign clinical course. Spontaneous regression of LM is common in children, with fading and narrowing of the pigmented band, or even complete disappearance. The vast majority of pediatric LM cases can be managed conservatively with regular follow-up, including clinical photography and onychoscopy.