Acquired (digital) fibrokeratoma

AK Jaiswal, M Chatterjee

 Department of Skin and STD, Base Hospital, Barrockpore, West Bengal - 743 101, India

Correspondence Address:
A K Jaiswal
Department of Skin and STD, Base Hospital, Barrockpore, West Bengal - 743 101
India

Introduction

The term Acquired Digital Fibrokeratoma (ADF) was first coined by Bart et al in 1968.[1] It has a characteristic, natural history and histology. Clinically, the lesion is usually relatively small, solitary, dome/ bullet shaped, with a colarette of slightly raised skin at its base. It may occasionally be elongated or pedunculated.[2] Histopathologically, the lesion shows a fibrous dermal core having both interwoven and parallel arrangements of collagen, with a thick keratotic covering. Herein, we report a case of this uncommon entity at an unusual site.

Case Report

A 38 - year-old soldier presented with an asymptomatic growth over the inner aspect of left heel of one-year duration. After an initial growth phase of several weeks, the lesion stabilised, but did not regress. It was not painful;nor did it itch or bleed even after trauma. He gave history of several repeated minor injuries priorto the onset of the lesions. There was no family history of skin disease.

Physical examination demonstrated a solitary, skin coloured, 1.5 x 2-cm, bullet shaped, pedunculated, firm lesion on the medial margin of left heel [Figure - 1]. The tumour was surrounded by a depression, which had a hyperkeratotic edge [Figure - 2]. Rest of the physical examination was unremarkable.

Histopathological examination showed epidermal hyperkeratosis, hypergranulosis, acanthosis and variable papillomatosis. The markedly thickened epidermis formed a dense envelope for the tumour. The dermis showed dense interwoven bundles of collagen fibres in the centre of the lesion. These were arranged haphazardly for the most part, but there were areas where the fibres were parallel to the vertical axis [Figure - 3].

The patient was diagnosed on the basis of clinical and histopathological findings as a case of acquired digital fibrokeratoma and managed with excision with no evidence of recurrence in the past 2 years.

Discussion

ADF is a benign, fibro - epithelial tumour of acquired nature. The aetiology is unknown. However, trauma seems to be a contributing factor. It is predominantly, though not exclusively, located on fingers and toes near the phalangeal joints. Occurrence of lesions on palms and soles is uncommon. ADF must be differentiated from other cutaneoustumours, particularly fibroma, cutaneous horn, Koenen′s tumour and eccrine poroma. The only possible treatment is surgical excision.

Our case is remarkable because of its large size and unusual location. To the best of our knowledge, only two cases of almost similar size and site have been reported in the literature so far.[3],[4] This report also further supports the view of Verallo[5] and Hemric et al[6] that since these lesions have been noted to occur in areas other than the digits, a more appropriate designation may be ′acquired fibrokeratoma′.

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