Редкое доброкачественное новообразование на ногте: описание клинического случая онхопапилломы

A 35-year-old man presents with a 2-year history of an abnormal nail growth involving a single digit associated with intermittent tenderness. He reports gradual enlargement of the lesion over time. He denies preceding trauma, bleeding, drainage, or pigmentary change. No prior treatments have been attempted. He otherwise feels well without additional skin or nail concerns. On physical examination, there is a localized dystrophic nail plate abnormality involving a single digit with associated longitudinal erythronychia and subungual hyperkeratotic growth (Figures 1 and 2). Mild tenderness is elicited with palpation. No surrounding erythema, drainage, or ulceration is appreciated. The remainder of the skin and nail examination is unremarkable. Onychopapilloma is a rare benign neoplasm of the nail bed and distal matrix characterized by papillomatous acanthosis and abnormal keratinization of the distal nail unit.1,2 Historically, the lesion was considered a reactive or hyperplastic process; however, its consistent clinicopathologic features... Submit your diagnosis to see full explanation. Onychopapilloma is a rare benign neoplasm of the nail bed and distal matrix characterized by papillomatous acanthosis and abnormal keratinization of the distal nail unit.1,2 Historically, the lesion was considered a reactive or hyperplastic process; however, its consistent clinicopathologic features and localized proliferation support classification as a true benign neoplasm of the nail bed epithelium.3 Generally benign and slow-growing, onychopapilloma most commonly presents as longitudinal erythronychia involving a single nail, although leukonychia, melanonychia, or splinter hemorrhages may also occur.1-3 Distal subungual hyperkeratosis is a characteristic finding and often produces a keratotic mass beneath the free edge of the nail plate.1-3 Lesions are usually asymptomatic but may occasionally cause tenderness, discomfort, or cosmetic concern.2 Fingernails, particularly the thumb, are affected more frequently than toenails.2,3 Diagnostic evaluation relies on clinicopathologic correlation. From a histopathologic standpoint, onychopapilloma demonstrates papillomatosis and acanthosis of the nail bed epithelium with matrix metaplasia characterized by cells resembling those of the nail matrix containing eosinophilic cytoplasm.2-4 Subungual hyperkeratosis is commonly present, and the epithelium may exhibit digitated projections extending into the underlying dermis.2-4 Cytologic atypia is absent or minimal, helping distinguish the lesion from malignant nail unit neoplasms.3 Management typically involves longitudinal excision of the affected nail bed and associated lesion, often with partial nail plate avulsion, to adequately visualize the tumor.1,3 Recurrence is uncommon following complete removal, and prognosis is excellent.1,3 Because longitudinal erythronychia may rarely reflect malignant pathology, histopathologic examination remains important to exclude nail unit squamous cell carcinoma or melanoma.1 Rachael Johnson is a medical student at the Baylor College of Medicine. Anna Catinis, MD, is a dermatology resident at the Baylor College of Medicine. References - Dermatology Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. 5th ed. Elsevier; 2024. - Kim TR, Bae KN, Son JH, et al. Onychopapilloma: its clinical, dermoscopic and pathologic features. J Eur Acad Dermatol Venereol. 2022;36(11):2235-2240. doi:10.1111/jdv.18461 - Starace M, Alessandrini A, Ferrari T, Wong V, Baraldi C, Piraccini BM. Clinical and onychoscopic features of histopathologically proven onychopapillomas and literature update. J Cutan Pathol. 2022;49(2):147-152. doi:10.1111/cup.14119 - Tosti A, Schneider SL, Ramirez-Quizon MN, Zaiac M, Miteva M. Clinical, dermoscopic, and pathologic features of onychopapilloma: a review of 47 cases. J Am Acad Dermatol. 2016;74(3):521-526. doi:10.1016/j.jaad.2015.08.053