Dermatology Online Journal

A case of acquired digital fibrokeratoma accompanied by pyogenic granuloma
Doo Rak Lee MD, Jung Yeon Lee MD, Ji Young Ahn MD, Mi Youn Park MD
Dermatology Online Journal 15 (1): 8

Department of Dermatology, National Medical Center, Seoul, Korea. doorak@hanmail.net

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Abstract

A 35-year-old male presented with a slowly growing keratotic tumor on the plantar aspect of his left second toe. Over a ten-year period, the projecting tumor had grown to the size of 7 x 18 mm without causing any symptoms. Three months prior to presentation, a red and polypoid papule of 5 x 5 mm-size began to develop within the original tumor. The tumor was diagnosed as acquired digital fibrokeratoma accompanied by pyogenic granoloma. Hereby, we report this unusual case.

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Introduction:

Acquired digital fibrokeratoma is a benign tumor of fibrous tissue that usually develops on acral areas such as the fingers and toes [1, 2]. It occurs in adults as a solitary, smooth, dome-shaped or finger-like, flesh-colored nodule [2, 3, 4], which may show a characteristic horn-shaped and projecting configuration. Minor trauma or repetitive irritation has been suggested as a predisposing factor [5], but the exact pathogenesis is not clarified yet. We report an interesting case of fibrokeratoma accompanied by pyogenic granuloma on the plantar aspect of the second toe.

Case report

Figure 1a	Figure 1b
Figure 1a. Solitary, projecting, keratotic mass accompanied by a reddish, polypoid papule on the plantar aspect of his left second toe Figure 1b. Close-up view

A 35-year-old male presented with a slowly growing keratotic tumor on the plantar aspect of his left second toe (Figs. 1a & 1b). Over a ten-year period, the projecting tumor had grown to a size of 7 x 18 mm without causing any symptoms. Three months prior to presentation, a red and polypoid 5 X 5mm papule began to develop. The corn-shaped tumor was 7 mm in diameter and 18 mm in height.

Figure 2
Figure 2. The epidermis shows hyperkeratosis and acanthosis. The dermis is packed with thick collagen bundles. The tumor is accompanied by the polypoid red papule. (H & E, scan view)

After complete excision of the tumor, the histopathology review revealed hyperkeratosis, parakeratosis and acanthosis of the epidermis. The dermis was packed with thick collagen bundles, which were arranged in parallel to the axis of the tumor (Figs. 2 & 3). Proliferating fibroblasts were also found in the dermis. However, the polypoid papule showed an angiomatous proliferation of ectatic capillaries suggesting a pyogenic granuloma or granulation tissue possibly due to recurrent trauma (Fig. 4). The patient was diagnosed as having an acquired digital fibrokeratoma accompanied by pyogenic granuloma or granulation tissue. There has been no recurrence in 12 months since the surgical excision.

Figure 3	Figure 4
Figure 3. The core of the tumor consists of thick collagen bundles, which are arranged parallel to the axis of the tumor. Proliferating fibroblasts and capillaries are also found in the dermis. (H & E, x40) Figure 4. The polypoid papule shows angiomatous proliferation of ectatic capillaries suggesting pyogenic granuloma. (H & E, x40)

Discussion

Acquired digital fibrokeratoma is a rare benign skin tumor that usually develops on the distal extremities, especially fingers and toes [1, 2, 6]. Most of them are found in adults as a solitary lesion [2, 3]. They are seen more often in men than in women and the average age of onset is 40 years [7]. Although acquired digital fibrokeratoma is frequently found on distal extremities, a few cases may be found on the elbow, wrist, calf, and the prepatellar area [2, 3]. It usually develops as an asymptomatic, smooth, dome-shaped, flesh-colored papule or nodule. In addition, the presence of a collarette is a characteristic finding of this disorder [1, 6]. Frequently, fibrokeratoma may be misdiagnosed as other common growths, such as verruca vulgaris, supernumerary digit, Koenen tumor in tuberous sclerosis, pyogenic granuloma, acrochordon, cutaneous horn, or neurofibroma [1, 6]. However, fibrokeratoma is resistant to standard wart treatment [6]. Supernumerary digits are usually congenital, are located on the proximal portion of the fifth digit, and histologically contain abundant nerve bundles [1, 2]. Also, a collarette would not be a characteristic finding of a supernumerary digit. Minor trauma or repetitive irritation has been suggested as a predisposing factor of fibrokeratoma [7, 8]. In this case, chronic long-standing irritation due to exercise may explain the development of fibrokeratoma. The accompanied red papule had developed over a period of three months, possibly as a result of repeated trauma from rubbing, scratching, and pulling.

Histopathologically, fibrokeratoma is a benign tumor of fibrous tissue. The epidermis is orthokeratotic, hyperkeratotic, papillomatous, and acanthotic. The dermis is packed with thick collagen bundles that are arranged parallel to the axis of the tumor.

Pyogenic granuloma is a common, acquired, benign vascular growth of the skin and mucous membranes, which usually presents as a solitary red papule. It grows rapidly and may become pedunculated. Histologically, pyogenic granuloma is composed of numerous newly formed capillaries; it occurs commonly during pregnancy and in response to trauma. The concurrence of acquired fibrokeratoma and pyogenic granuloma or acute granulation tissue probably relates to repeated trauma at this site.

References

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