Nevus comedonicus syndrome: A systematic review of the literature

[Main Types of Cysts in Dermatopathology: Part 1]

Cystic structures represent one of the most common findings in dermatopathology. These encompass both cystic tumors and pseudocysts resulting from the accumulation of certain substances, such as mucin. In a two-part series (of which this is the first part), we have reviewed the principal types of cysts and pseudocysts that may be observed in cutaneous biopsies, examining their histopathological features and primary differential diagnoses. This first part encompasses infundibular cysts, eruptive dermoid cysts, pigmented follicular cysts, pilonidal cysts, tricholemmal cysts, milium cysts, hybrid cysts, bronchogenic cysts, as well as steatocystoma, hydrocystoma, and comedones.

Nevus comedonicus: A case report with the histological findings and brief review of the literature

INTRODUCTION

Nevus comedonicus (NC) is a rare cutaneous disorder thought to be caused by hamartomatous pilosebaceous tissue proliferation that was first described in 1895. Clinically NC appears as a group of elevated follicular openings often linearly arrayed, giving the appearance of comedones. NC usually manifests at birth but can also present later during adolescence and rarely in adulthood.

CASE PRESENTATION

A 21-year-old medically healthy single male presented with right-sided chest black papules in comedo distribution with areas of superficial ulcerations and suppurations in periareolar distribution since the age of 16. Histopathological examination showed dilated follicular ostia filled with keratin plug, devoid of the hair shaft, and lined by stratified squamous epithelium with compact hyperkeratosis, focal parakeratosis, and patchy atrophy and acanthosis.

CLINICAL DISCUSSION

Nevus comedonicus often responds effectively to conservative treatment, however some cases need surgery intervention. The patient failed conservative medical and topical treatment, and he was treated by surgical-wide local excision and primary closure of the affected skin with free nipple grafting.

CONCLUSION

Nevus comedonicus (NC) is a rare cutaneous pathology secondary to pilosebaceous apparatus developmental defect that usually manifests at birth and can affect any area of skin; they typically manifest as black papules in comedo distribution. They can present as an isolated cutaneous pathology or as a component of nevus comedonicus syndrome. Different therapeutic approaches were described, including topical retinoids, keratolytic agents, oral retinoids, antibiotic therapy, manual extraction of comedos, dermabrasion, and surgical resection of the lesion.

Epidermal Nevi: What Is New

This article reviews the clinical findings of epidermal nevi and their associated syndromes and provides an update on their pathogenic genetic changes as well as targeted therapies detailed to date.