Dilated pore of winer

Introduction

Dilated Pore (DP) was first reported by Winer in 1954.[1] DP was seen predominantly in young adult males as a solitary brown to black, giant comedo with central pore, which is nonpalpable due to lack of infiltration.[2] DP was evaluated as an adnexal benign tumour with follicular differentiation although infrequently.[3] Histopathologically DP is characterized by markedly dilated infundibulum lined by thin epidermis near the ostium and acanthotic, hypertrophic epidermis with thin strands invading dermis plus subinfundibular atrophy of hair structures in its deeper part.[4] Comedo naevus (CN) appears at birth or childhood or adolescent, grows rapidly at puberty, is unilateral and linear, reveal group of pits filled with black keratinous plugs, associated with frequent episodes of infection and are seen on face, trunk and upper arms.[5] Although clinical lesions of DP and solitary lesion of CN are almost identical clinically yet, final differentiation is possible on histopathology.

Case Reports

Case 1: A 27- year-old man presented with solitary, dark-black, non palpable, 7 mm, well defined papule with elevated margins and 2 mm central pore on nose since 3 years. At times discharge of black material was observed especially in mornings after pressing it. An excision biopsy was performed. Histopathology showed greatly dilated infundibulum lined by acanthotic epidermis and subinfundibular atrophic structures thus confirming the clinical diagnosis of DP He had recurrence of lesion at the same site after 7 months.

Case 2: A 26 -year-old man visited Dermato Venereology department with asymptomatic dark black, 9mm, oval papule with well defined elevated margin, central pore, discharging powdery black material occasionally, on the extensor aspect of right forearm since 9 months [Figure - 1]. Incomplete curettage of above lesion was tried earlier by some dermatologist without any benefit. Deep and wide excision biopsy was done and lesion healed completely after 10 days. Histopathologically greatly dilated infundibuium lined by acanthotic epidermis and atrophic subinfundibulurn hair structures confirmed the diagnosis of DP.

In addition, similar (2-3mm) nine discrete black papules were observed on right forearm and lower abdomen.

Discussion

The exact etiopathogenesis of DP is not known. Some studies propose it to be a histological variant of CN,[4] while others consider it to be an adnexal tumour of follicular differentiations.[3] Classical DP and CN can be easily differentiated clinically.[2],[5] They are two distinct entities as histopathologically also, DP of Winer has markedly dilated infundibulum filled with keratin and subinfundibular atrophic hair structures whereas CN reveals epidermal invagination with keratin plugs.[4] Due to late age of onset and characteristic histopathology DP of Winer should be considered as an adnexal benign tumour with follicular differentiation rather than a naevus.

Although DP lacks infiltration yet pore seems to be deep one as recurrence occurred in case no.1 probably due to superficial nature of biopsy and therefore excision biopsy should be deep in case of DR.