Acquired Digital Fibrokeratoma

Also known as an Acral Fibrokeratoma

Are You Confident of the Diagnosis?

What you should be alert for in the history

Patients often present complaining of an asymptomatic growth on the hand or foot.

Characteristic findings on physical examination

These lesions are characterized by a flesh-colored hyperkeratotic protuberence surrounded by a collarette of surrounding skin. Lesions usually measure 4-8 mm in diameter, but lesions up to 3 cm have been reported.

Expected results of diagnostic studies

When submitted for histologic examination, sections show a well-defined papule with a narrow stalk (Figure 1). Surrounding this stalk, a rim of epidermis forms a collarette. Overlying an acanthotic epidermis is a layer of hyperkeratosis resembling acral skin. A thick core of vertically oriented collagen surrounded by fine capillaries and connective tissue is present at the center of the lesion (Figure 2).

Figure 1.

Acquired digital fibrokeratoma (X10). Note the narrow stalk of the papule.

Figure 2.

Acquired digital fibrokeratoma (X40). Vertically oriented collagen at the center of the lesion.

Differential Diagnosis

Verruca vulgaris may mimic an acquired digital fibrokeratoma. Verrucae are caused by human papilloma virus and are spread by contact. They are distinguished from acquired digital fibrokeratomas by the lack of a collarette and a rough hyperkeratotic surface. Multiple verruca are often present, whereas acquired digital fibrokeratoma are solitary.

Pyogenic granulomas are rapidly growing vascular tumors that often occur on the hands. These lesions have a collarette surrounding the base, but have a friable core that bleeds easily.

Supernumerary digits are similar in appearance to acquired digital fibrokeratomas, but are present in birth. They represent a duplication of a digit with a tissue core of bone, cartilage, and/or neural tissue.

Periungual fibroma (Koenen’s Tumor) is associated with Tuberous Sclerosis. These lesions are hyperkeratotic growths that occur around the nails and may cause nail dystrophy. They begin to develop in late childhood and increase in number with age. Periungual fibromas may also appear to have a collarette, but this usually represents the distorted nail fold. The location, multiple lesions, and lack of a true collarette differentiate these lesions from an acquired digital fibrokeratoma.

Squamous cell carcinoma can also mimic an acquired digital fibrokeratoma. These lesions often occur in middle-age and older individuals with a significant amount of sun exposure. Squamous cell carcinoma does not have a collarette, but may have a hyperkeratotic, rough surface. Bleeding and ulceration may occur. Often these lesions have a history of slow continued growth and are not confined to a small, narrow base.

Acquired periungual fibrokeratomas are rare tumors that form on the nail fold that are histologically identical to an acquired digital fibrokeratoma.

Who is at Risk for Developing this Disease?

This benign lesion may occur at any age, but most commonly affects middle-age patients. Both sexes and all ethnic groups may be affected. The development of acquired digital fibrokeratomas is spontaneous and without any association with other medical conditions.

What is the Cause of the Disease?

While no known cause for the formation of this lesion has been shown, it may represent an abnormal healing reponse to mild trauma.

Systemic Implications and Complications

There are no associations with any other disease states.

Treatment Options

Surgical options

Surgical excision

Carbon dioxide laser ablation

Cryosurgery

Electrodessication and curettage

Optimal Therapeutic Approach for this Disease

Simple surgical excision is the best method for removing an acquired digital fibrokeratoma. Simple saucerization with application of ointment such as vaseline and a bandage will allow healing of the site within 1 to 2 weeks. Other destructive methods including laser, cryosurgery, and electrodessication can also be employed if surgical excision cannot be employed. These methods also heal in 1 to 2 weeks, but have a higher risk of developing a cosmetically unappealing scar.

Patient Management

Acquired digital fibrokeratomas uncommonly recur weeks to months after surgical excision or destruction. If lesions recurs, excision or destruction should be repeated.

Unusual Clinical Scenarios to Consider in Patient Management

Acquired digital fibrokeratomas are usually solitary lesions. If patient have multiple lesions, they may represent Koenen tumors and the patient should be assessed for tuberous sclerosis.