Extensive unilateral nevus comedonicus with bilateral involvement of face

Introduction

Nevus comedonicus is an uncommon skin abnormality, first described in 1895 by Kofmaim.[1] Beerman and Homan[2] analysed 100 cases and concluded that lesions may appear any time, from birth to middle age but are usually present at birth or develope before the age of 10 years. Clinically nevus comedonicus presents as asymptomatic groups of pits, filled with black keratinous plugs. The intervening epidermis may be normal, slightly hypo or hyperpigmented. Lesions may be extensive and diffuse. The most commonly affected site is face, followed by neck, trunk, upper arms. The scalp, palms, soles and glans penis may occasionally be involved.[3] Paige et al,[4] reported a case of nevus comedonicus with bilateral involvement along with scalp lesions associated with whitening of hair. In this condition, there is defect or failure in the development of mesodermal component of pilosebaceous complex with coincident imperfect differentiation of the epidermal component. The follicular structure that results is not able to form matrix cells or hairs and capable of forming only soft keratin which plugs. the adnexal orifice and produces the comedones.[5] The sebaceous glands may be well developed, hypoplastic or absent but never hypertrophic as occurs in nevus sebaceous.[4] Clinically nevus comedonicus can be divided into two types, one in which only comedonal lesions are present, other in which comedones undergo inflammatory changes with late sequellae being scars, keloids, fistulae and follicular cyst formation.[4] Histopathology may reveal rudimentary hair follicles, sebaceous glands, trichilemmal cyst, dyskeratosis, and epidermolytic hyperkeratosis.[6] [Figure - 1]

Case Report

An 18 - year - old man presented with asymptomatic grouped comedo-like keratin filled pits on left side of his forehead, over zygomatic area and on right cheek since the age of 3 months. In due course of time multiple groups of similar lesions developed over right side of the trunk, arm and forearm, up to the age of 10 years. These lesions progressively enlarged during the last 5-6 years. Patient also had multiple painful fibrotic masses, and infected cysts over right half of the trunk since 3-4 months, the left half of the trunk, left upper limb, palms, scalp, genitalia and lower limbs were sharply spared. The family history was negative. Examination revealed multiple groups of dilated pilosebaceous orifices filled with balck keratin plugs over left side of his forehead and zygomatic area and on the right side over cheek, trunk and upper limb. All routine investigations were within normal limits. Histopathological findings were suggestive of nevus comedonicus.

Discussion

Nevus comedonicus is usually present at birth but in our case lesions first appeared over right cheek at the age of 3 months and then over the trunk at the age of 10 years and then there was progressive pubertal enlargement. Such extensive, non-familial, unilateral nevus comedonicus with bilateral facial involvement, of late onset and pubertal enlargement is uncommon.