# Histopathological Characterization and Differential Expression of miRNAs in Male Pediatric Patients With Lichen Sclerosus

## TL;DR

This study examines skin inflammation patterns and miRNA expression in young boys with lichen sclerosus, identifying potential biomarkers for diagnosis and treatment.

## Contribution

The study identifies specific miRNAs associated with lichen sclerosus in pediatric male patients, offering potential diagnostic and therapeutic insights.

## Key findings

- Four distinct histopathological inflammation patterns were identified in lichen sclerosus patients.
- Several miRNAs were significantly upregulated or downregulated in lichen sclerosus tissue compared to normal tissue.
- Younger prepubertal patients showed higher inflammation grades and miRNA expression levels.

## Abstract

Lichen sclerosus is a chronic, inflammatory, scarring disease of the skin that manifests mostly in the genital region.

We studied the histomorphological characteristics, grade, and pattern of inflammation in male pediatric patients with lichen sclerosus. We also compared the expression of selected miRNAs in lichen sclerosus tissue, adjacent non‐lichen sclerosus tissue from the same patient, and healthy male pediatric patients.

According to the type of inflammation/lymphocytic distribution, we categorized patients into four groups with the following features: (i) dominant lichenoid basal superficial inflammation, (ii) dominant band‐like lymphocytic infiltration in the papillary sublayer of the dermis, (iii) mixed lymphocytic inflammation combining both patterns, and (iv) lymphocytic depletion with extensive fibrosis. The extent of inflammation was graded, with patients being categorized into weak, moderate, and strong inflammation groups. In terms of miRNA expression, hsa‐miR‐146a‐5p, hsa‐miR‐146b‐5p, hsa‐miR‐150‐5p, and hsa‐miR‐155‐5p were significantly upregulated, and hsa‐miR‐199b‐5p and hsa‐miR‐200b‐3p were significantly downregulated in lichen sclerosus tissue compared with adjacent normal tissue as well as normal tissue from male pediatric non‐lichen sclerosus patients (p < 0.001). Hsa‐miR‐30b‐5p was significantly downregulated in lichen sclerosus patients compared with male pediatric non‐lichen sclerosus patients (p < 0.001). Pediatric male lichen sclerosus patients were categorized into two groups according to median age (≤9 years vs. >9 years); the early onset prepubertal patients presented, on average, a higher grade of inflammation (p = 0.020) and significantly higher miRNA hsa‐miR‐150‐5p (p = 0.049) expression compared to the older group.

Histopathological investigations can distinguish lichen sclerosus patient groups with different extents of disease. miRNAs could serve as candidate diagnostic markers for lichen sclerosus in pediatric male patients and may represent future therapeutic targets.