eMedicine Specialties > Dermatology > Benign Neoplasms
Acquired Digital Fibrokeratoma
Updated: Sep 10, 2009
Introduction
Background
In 1968, Bart et al1 described 10 cases of an uncommon acquired growth that was located on the fingers. Although it clinically resembled a cutaneous horn or rudimentary supernumerary digit, it had distinct histopathological findings. The authors named this growth acquired digital fibrokeratoma (ADFK). Subsequently, Pinkus2 reported 28 more cases; however, because the lesions Pinkus described also occurred on the proximal hand, toes, soles, and one in the prepatellar region, he suggested the entity might be more appropriately called acquired acral fibrokeratoma.
An acquired periungual fibrokeratoma is similar to an acquired acral fibrokeratoma, differing primarily in that the former arises from the proximal nail fold. Koenen tumors, although similar, occur in association with tuberous sclerosis and histologically may have atypical stellate myofibroblasts.3
Pathophysiology
Despite the fact that most patients deny a history of precedent trauma, the major hypothesis is that subclinical injury contributes to the development of acquired digital fibrokeratomas.
Frequency
United States
Currently, no means of tracking nonmelanoma skin cancer, much less various benign dermatological conditions, are available in the United States; therefore, the actual incidence of acquired acral fibrokeratoma is unknown. Most cases of acquired digital fibrokeratoma reported in the literature involve individual case reports presented because of the lesions' unusual size, location, histological features, or association with other conditions. Only a few reports of describe a series of patients, with 50 patients being the most reported from any one institution.4 Therefore, whether acquired digital fibrokeratoma is rare or rarely reported remains unclear.
Mortality/Morbidity
Acquired digital fibrokeratomas are benign stationary lesions that are more cosmetically bothersome than they are problematic. However, patients who have been reported to have giant acral digital fibromas on the dorsum or plantar surface5,6 of the foot may report some discomfort.
Race
Acquired digital fibrokeratomas have been reported in persons of all races.
Sex
Acquired digital fibrokeratomas seem to have a slight male predominance; however, at this time too few cases have been described to adequately assess the significance of any sexual predilection.7
Age
The patients reported with acquired digital fibrokeratomas range in age from 12-70 years, with most cases occurring in middle-aged adults. Clinically similar lesions that occur in young children are more likely to represent rudimentary supernumerary digits.
Clinical
History
Most acquired digital fibrokeratoma patients present with an asymptomatic protuberance.
Physical
Clinically, acquired digital fibrokeratomas manifest as solitary, skin-colored, dome-shaped papules or tall fingerlike protrusions with a hyperkeratotic surface. Most acquired digital fibrokeratoma lesions are small and do not exceed 1.5 cm in height or diameter, but giant lesions measuring in excess of 3 cm have been documented.8
An important clinical finding reported to help differentiate acquired digital fibrokeratomas from other similar lesions is a collarette of slightly raised skin that encircles the base of the lesion, thereby creating a moatlike configuration.9
Clinical picture of a pedunculated acquire digital fibrokeratoma.
Flat-topped, skin-colored acquired digital fibrokeratoma in an acral location.
Slightly raised skin encircling the base of an acquired digital fibrokeratoma, creating a moat.
Causes
The etiology of acquired digital fibrokeratomas is unknown. Although trauma has been implicated, no studies can substantiate this hypothesis.
One report describes familial occurrence of an acral fibrokeratoma variant that had mucinous deposition; however, the case reported by Moulin et al10 histologically more closely resembles a superficial acral fibromyxoma.
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References
Bart RS, Andrade R, Kopf AW, Leider M. Acquired digital fibrokeratomas. Arch Dermatol. Feb 1968;97(2):120-9. [Medline].
Pinkus H. Discussion - Acquired digital fibrokeratoma. Arch Dermatol. 1968;97:128-9.
Carlson RM, Lloyd KM, Campbell TE. Acquired periungual fibrokeratoma: a case report. Cutis. Aug 2007;80(2):137-40. [Medline].
Kint A, Baran R. Histopathologic study of Koenen tumors. Are they different from acquired digital fibrokeratoma?. J Am Acad Dermatol. Feb 1988;18(2 Pt 1):369-72. [Medline].
Bron C, Noel B, Panizzon RG. Giant fibrokeratoma of the heel. Dermatology. 2004;208(3):271-2. [Medline].
Spitalny AD, Lavery LA. Acquired fibrokeratoma of the heel. J Foot Surg. Sep-Oct 1992;31(5):509-11. [Medline].
Baykal C, Buyukbabani N, Yazganoglu KD, Saglik E. Acquired digital fibrokeratoma. Cutis. Feb 2007;79(2):129-32. [Medline].
Kakurai M, Yamada T, Kiyosawa T, Ohtsuki M, Nakagawa H. Giant acquired digital fibrokeratoma. J Am Acad Dermatol. May 2003;48(5 Suppl):S67-8. [Medline].
Vinson RP, Angeloni VL. Acquired digital fibrokeratoma. Am Fam Physician. Oct 1995;52(5):1365-7. [Medline].
Moulin G, Balme B, Thomas L. Familial multiple acral mucinous fibrokeratomas. J Am Acad Dermatol. Jun 1998;38(6 Pt 1):999-1001. [Medline].
Kumari R, Thappa DM, Devi A. Periunungal acquired digital fibrokeratoma. Indian J Dermatol Venereol Leprol. 2009;75:72.
Dominguez-Cherit J, Garcia C, Vega-Memije ME, Arenas R. Pseudo-fibrokeratoma: an unusual presentation of subungual squamous cell carcinoma in a young girl. Dermatol Surg. Jul 2003;29(7):788-9. [Medline].
Chi CC, Kuo TT, Wang SH. Aggressive digital papillary adenocarcinoma: a silent malignancy masquerading as acquired digital fibrokeratoma. Am J Clin Dermatol. 2007;8(4):243-5. [Medline].
Kint A, Baran R, De Keyser H. Acquired (digital) fibrokeratoma. J Am Acad Dermatol. May 1985;12(5 Pt 1):816-21. [Medline].
Nickel WR, Reed WB. Tuberous sclerosis. Special reference to the microscopic alterations in the cutaneous hamartomas. Arch Dermatol. Feb 1962;85:209-26. [Medline].
Hare PJ, Smith PA. Acquired (digital) fibrokeratoma. Br J Dermatol. Sep 1969;81(9):667-70. [Medline].
Hemric JR, Allen HB. Acquired digital fibrokeratoma. Cutis. Mar 1979;23(3):304-6. [Medline].
Jaiswal AK, Chatterjee M. Acquired (digital) fibrokeratoma. Indian J Dermatol Venereol Leprol. May-Jun 2002;68(3):179-80. [Medline].
Saito S, Ishikawa K. Acquired periungual fibrokeratoma with accessory germinal matrix. J Hand Surg [Br]. Dec 2002;27(6):549-55. [Medline].
Verallo VV. Acquired digital fibrokeratomas. Br J Dermatol. Nov 1968;80(11):730-6. [Medline].
Further Reading
Keywords
acquired digital fibrokeratoma, ADFK, acral fibrokeratoma, acquired periungual fibrokeratoma, Koenen tumor, Koenen's tumor, garlic clove fibroma, subungual fibrokeratoma, periungual fibrokeratoma
