An Interesting Case Report of Acquired Triradiate Periungual Fibrokeratoma and its Dermoscopic Features.

Abstract

Dear Editor, A 6-year-old girl attended our nail OPD (Out Patient Department) for an opinion on rapidly growing two finger-like projections at the proximal nail fold of her right fourth finger for 3 months. The growth was painless and asymptomatic. There was no history of trauma or any significant systemic disease. On clinical examination, there were two finger-like projections with keratotic tips that were fused proximally at the proximal nail fold of her right fourth finger. The underlying nail plate was normal except for the depression with a concave surface underneath the tumor. There was no evidence of a shagreen patch or angiofibroma on the face. There was no history of convulsions in the past or similar family history. On dermoscopy with DermLite DL4, contact polarized view at 10× magnification, we could appreciate two filiform rod-like projections with one more projection starting to grow from the side. There were five zones in each projection. From proximal to distal the zones were a white structureless zone, a red structureless area, a structureless brown area, a well-delineated dark brown area, and a lighter overhanging rim-like brown area at the distal-most end [Figure 1].Figure 1: Filiform projections (Dermoscopic view - Dermlite DL4,10X)We made a provisional diagnosis of acquired periungual fibrokeratoma. Our differentials were supernumerary digit, acral fibromyxoma, and wart.[1] The lesion was completely excised under a digital block. The proximal nail fold was everted by giving two incisions on either side of the growth and the tumor was exposed using stay sutures on either side. We dissected the tumor from the underlying nail plate and the overlying proximal nail fold. The tumor was excised in toto and sent for histopathology. The incisions were closed with 5–0 prolene and suture removal was done on day 10. The postoperative period was uneventful with no evidence of recurrence after 6months and the patient was kept on follow-up. On histopathology, the finger-like projections [Figure 2] were seen which were lined by horny hyperkeratosis, hypergranulosis, acanthotic epidermis with the dermis showing dense collagen fibers, dilated thin-walled capillaries, and fibroblasts [Figure 3].[2]Figure 2: Finger-like projections lined by hyperkeratosis, hypergranulosis, and acanthotic epidermis (H & E, 4×)Figure 3: The dermis with dense collagen fibers, dilated thin capillaries, and fibroblasts (H & E, 40×)The dermoscopic and histopathological correlation of this case is as follows [Table 1].Table 1: Dermoscopic and Histopathologic correlationBased on the clinical, dermoscopic, and histopathological correlation, the diagnosis of Type 2 acquired periungual fibrokeratoma (AUFK) was made. AUFK are benign fibrokeratotic tumors.[3]The classical presentation of AUFK is an asymptomatic single-skin colored nodule with a hyperkeratotic tip emerging from the proximal nail fold or directly from the nail bed. The pathogenesis is not yet validated; however, the role of trauma, presence of factor XIIIa positive dermal dendrocytes, preceding streptococcal infection, and human papillomavirus infection[4]have been postulated as the etiological factors. The rare variant of AUFK called multibranched acquired periungual fibrokeratoma was first described in 2014 by Moriue et al.[5] In this letter, we describe one such entity which was successfully diagnosed and treated. AUFK typically affects middle-aged adults with slight male predominance. It is more often localized to toe nails rather than fingernails, most commonly in the periungual area. Our case is unique due to its occurrence in fingernails, and its presentation during the first decade of life in a female. In this, we tried to correlate the histopathological and dermoscopic findings which might help in the preoperative diagnosis of this condition. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.