Clinical Dermatology Review

: 2020  |  Volume : 4  |  Issue : 2  |  Page : 189--190

Acquired onychoheterotopia with acquired digital fibrokeratoma

Elreema Fernandes, Varadraj Pai, Pankaj Shukla 
 Department of Dermatology, Goa Medical College, Bambolim, Goa, India

Correspondence Address:
Varadraj Pai
Department of Dermatology, Goa Medical College, Bambolim, Goa

How to cite this article:
Fernandes E, Pai V, Shukla P. Acquired onychoheterotopia with acquired digital fibrokeratoma.Clin Dermatol Rev 2020;4:189-190

How to cite this URL:
Fernandes E, Pai V, Shukla P. Acquired onychoheterotopia with acquired digital fibrokeratoma. Clin Dermatol Rev [serial online] 2020 [cited 2020 Oct 26 ];4:189-190
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Ectopic nail or onychoheterotopia is an uncommon clinical entity characterized by the nail tissue which grows outside the classic nail unit of the dorsal fingers and toes.[1] Acquired digital fibrokeratomas are uncommon benign fibrous tumors located in the ungual area.[2] They present as asymptomatic solitary, smooth, dome-shaped or finger-like, flesh-colored papules.[2] Here, we report a case of acquired onychoheterotopia with acquired digital fibrokeratomas in the same finger.

A 19-year-old male presented to our outpatient department with a history of extra nail growing from the right middle finger and also an asymptomatic growth arising from the distal end of the same finger. According to the parents, both these abnormalities were present in childhood but not during birth. There was a history of acute trauma during childhood.

On examination, a hard keratinized miniature nail was seen, emerging from the proximal nail fold on the medial side. Both normal and accessory nails showed longitudinal grooving and trachyonychia. A 5-mm skin-colored firm elongated papule was seen arising from the proximal nail fold, impinging on the lateral side of the nail on the lateral side. It was associated with mild tenderness [Figure 1]. A differential diagnosis of rudimentary digit with an ectopic nail and acquired digital fibrokeratomas was made, and X-ray of the hand was done. X-ray revealed no abnormality of the distal phalanx [Figure 2]. Hence, a diagnosis of acquired ectopic nail with acquired digital fibrokeratomas was made. The patient did not consent for biopsy.{Figure 1}{Figure 2}

Ectopic nails are usually congenital; the acquired variety is less common.[1] Acquired ectopic nail is usually an outcome of trauma to the nail unit which may in turn result in inoculation of the nail matrix to the distal site, causing the ectopic nail growth.[3],[4] This must be the probable reason in our case leading to the displacement of matrix onto the dorsum of the finger.

Congenital ectopic nail may either be because of an ectopic existence of germ cells or the nail of a rudimentary or hidden polydactyly. It may be seen in Pierre Robin syndrome and an aberration of the long arm of chromosome 6.[5] The congenital is most often seen on the palmar aspect of the fifth digit, followed by the palmar aspect of the fourth, first, third, and the second digits,[6],[7] while the posttraumatic form is most often seen on the dorsal aspect of the hand.[1]

The ectopic nail may grow horizontally or vertically. Vertical growth is identified in places where there is incomplete or lack of proper nail fold or nail bed. Circumferential pattern is also known.[1],[3] Pain, irritation, infection, and interference with growth of the distal normal nail due to impingement onto its matrix are its complications.[1] This was seen in our patient causing slow growth of the normal nail.

The differential diagnosis of this condition includes a foreign body, rudimentary polydactyly, teratoma, hamartoma, split nail deformity, and cutaneous horn.[1] The presence of a rudimentary polydactyly should be ruled out by an X-ray before embarking upon the treatment of an ectopic nail.[8]

Complete excision of the ectopic nail with its matrix, preserving the matrix of the normal nail, is important for the prevention of recurrence and maintaining cosmesis.[8]

Acquired digital fibrokeratoma presents as a solitary, elongated, or dome-shaped lesion with a characteristic collarette of raised skin at the base.[9] They usually present as lesions that emerge from the proximal nail fold or sometimes from the nail bed.[10] Acquired periungual fibrokeratoma is considered as a topographical variant of acquired digital fibrokeratoma, but it has a unique “garlic clove” shape.[11]

Hare and Smith proposed that trauma is involved; while Nemeth and Penneys reported that factor XIIIa-positive dermal dendritic cells play an important role in the regulation of collagen.[12],[13] A traumatic origin has been suggested because acquired ungual fibrokeratomas occur most frequently on the fingers and toes.[14] Middle and ring fingernails as well as the great and fourth toenails were commonly affected, and these are the sites likely to be exposed to trauma or infection, supporting the above hypothesis.[12],[13] Histopathologic findings include hyperkeratosis, acanthosis, focal hypergranulosis, and irregular rete ridge elongation in the epidermis. The core of the tumor consists of thickened collagen in the dermis oriented parallel to the long axis of the lesion.[15] Clinically, the condition may be mistaken as a rudimentary, supernumerary digit, which occurs at the base of the fifth finger but is present since birth and usually bilateral.[16] Histologically, the presence of numerous nerve bundles at the base distinguishes the latter from acquired digital fibrokeratoma.[16] Other conditions to be differentiated are cutaneous horn, viral wart, and dermatofibroma. Periungual lesions are to be differentiated from Koenen tumor of tuberous sclerosis. The hyperkeratotic tip of the periungual lesion differentiates it from garlic-clove fibroma.[17]

Hwang et al. found in their study longitudinal grooving, trachyonychia, chromonychia, subungual hyperkeratosis, onycholysis, and dissected nail plates.[2] The groove is thought to be due to the fibrokeratoma originating from the underside of the proximal nail fold, compressing the nail matrix.[18] In our case also, the patient had longitudinal grooving and trachyonychia.

Acquired ungual fibrokeratomas do not spontaneously regress. They should be excised when they cause symptoms or significant cosmetic problems. The preferred treatment is total excision because superficial removal usually results in recurrence.[2]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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