DermDx: Painless Deformity of a Fingernail

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A 51-year-old woman is seeking treatment for distortion of a fingernail that was first noted several months ago. The patient has a history of hypertension but denies a history of diabetes, psoriasis, and lichen planus. She has never worn acrylic nails and cannot recall antecedent trauma to the finger. Examination reveals a depression adjacent to the lunula with interspersed splinter hemorrhages, which are accentuated on dermoscopy. Palpation of the nail does not elicit tenderness and no other nails are similarly affected. 

Onychomatricoma is a rare, benign neoplasm of the nail matrix.1 The tumor is most commonly diagnosed in middle-aged White women. No specific risk factors have been identified but trauma can be a precipitating factor in some cases.1 The tumor is...

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Onychomatricoma is a rare, benign neoplasm of the nail matrix.1 The tumor is most commonly diagnosed in middle-aged White women. No specific risk factors have been identified but trauma can be a precipitating factor in some cases.1 The tumor is more common in the fingers but it has been documented in the toes as well.2 It can involve a single or multiple digits.

Onychomatricoma is usually slow growing and painless. Physical findings may include thickening, splinter hemorrhages, and hypercurvative of the affected nail.3 Some cases have a yellow discoloration (xanthonychia). Onychomatricoma can project into the nail plate and produce characteristic honey-comb or woodworm projections.

Dermoscopic findings of onychomatricoma include distal nail plate perforations, longitudinal white lines, and hemorrhagic striae. Both ultrasound and magnetic resonance imaging (MRI) may aid in recognition and exclusion of other neoplasms.4,5

Definitive diagnosis is made by biopsy with findings dependent on whether the tumor is situated in the lunula or proximal nail fold.6 Following a nail avulsion, villous projections along with parallel cavitations and orifices of the nail matrix are considered classic findings of onychomatricoma. Surgical excision is the treatment of choice and recurrence is uncommon.

Sara Mahmood, DPM, is a podiatrist who completed a joint dermatology/podiatry fellowship and is on staff at the DermDox Dermatology Centers in Pennsylvania. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Borges Figueira de Mello CD, Noriega LF, Gioia Di Chiacchio N, Ocampo-Garza J, Di Chiacchio N. Onychomatricoma of the nail bed. Skin Appendage Disord. 2019;5(3):165-168. doi:10.1159/000494096

2. Rushing CJ, Ivankiv R, Bullock NM, Rogers DE, Spinner SM. Onychomatricoma: a rare and potentially underreported tumor of the nail matrix. J Foot Ankle Surg. 2017;56(5):1095-1098. doi:10.1053/j.jfas.2017.04.008

3. Jaeger TNG, Canella C, Leverone AP, Nakamura RC. Onychomatricoma with onychomycosis: a case report and review of the literature. Skin Appendage Disord. 2021;7(5):422-426. doi:10.1159/000516662

4. Cinotti E, Veronesi G, Labeille B, et al. Imaging technique for the diagnosis of onychomatricoma. J Eur Acad Dermatol Venereol. 2018;32(11):1874-1878. doi:10.1111/jdv.15108

5. Charfi O, Jaber K, Khammouma F, et al. Magnetic resonance imaging in the diagnosis of onychomatricoma: a case report. Skin Appendage Disord. 2019;5(4):246-250. doi:10.1159/000496474

6. Romero LS, Park H, Shoaee N, Cohen PR. Onychomatricoma presenting as a dystrophic right great toenail: case report and review. Cureus. 2020;12(5):e7946. doi:10.7759/cureus.7946

This article originally appeared on Clinical Advisor

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