Multibranched Acquired Periungual Fibrokeratoma

We have encountered a case of multibranched acquired periungual fibrokeratoma (APF).

A man in the sixth decade of life consulted us for an evaluation of small rodlike nodules at the proximal nail fold on his left fifth finger in May 2012. Six months previously, he noticed a small rodlike nodule, and 3 months later, he noticed another near the first nodule. Because the nodules had progressively enlarged, he sought medical advice. He reported no history of trauma before the onset of the lesions. He had a history of brain infarction and had left-sided hemiplegia and hypoesthesia. No other significant cutaneous or systemic diseases were reported by the patient.

On examination, 2 branching asymptomatic firm flesh-colored small rodlike nodules were seen arising beneath the proximal nail fold (Figure 1A). Keratotic materials were observed at the tip of the nodule. Both nodules seemed to be fused on the proximal nail fold. The nail plate under the lesion had a shallow and concave surface.

The lesion was completely excised under the proximal nail fold. Two small rodlike nodules were fused at the proximal end, and a third 2-mm small nodule, which branched off the other nodules, was found under the nail fold (Figure 1B [arrowhead]).

Histologically, the epidermis lacked rete ridges and showed hyperkeratosis (Figure 2). At the tip of the lesion, the horny layer showed marked hyperkeratosis. The collagen fibers were thick in the dermis.

There were no clinical signs indicating tuberous sclerosis. On the basis of clinical and histopathologic findings, the patient was diagnosed as having type I APF. No recurrence of the lesion was detected on follow-up, and the development of the new nail plate was normal.

Acquired periungual fibrokeratoma is a rare, nonmalignant, fibrous and hyperkeratotic periungual tumor that usually presents as a lesion emerging from the proximal nail fold or sometimes from the nail bed. The term acquired periungual fibrokeratoma was proposed by Cahn¹ because the lesion was thought to be histologically identical to acquired digital fibrokeratoma. Acquired periungual fibrokeratoma is classified into 2 groups: type I involves the nail plate and type II is derived from periungual lesions.²

The lesion in this patient branched into 3 parts. As far as we know, this case is the first to be reported with distinctly multibranched APF.^3,4 The exact pathogenesis of APF remains unclear. Trauma is often thought to be a predisposing factor. One case of APF with leprosy in which hypoesthesia may have played a role in the pathogenesis of APF has been reported.⁵ Although our patient had no history of trauma, he might not have noticed minor trauma because of the presence of hemiplegia and hypoesthesia due to brain infarction.

Corresponding Author: Tetsuya Moriue, MD, PhD, Department of Dermatology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan (moririn@med.kagawa-u.ac.jp).

Published Online: February 19, 2014. doi:10.1001/jamadermatol.2013.6631.

Conflict of Interest Disclosures: None reported.