A case of onychopapilloma presenting as longitudinal erythronychia.

A 50-year-old Asian male presented with a two-year history of a red linear streak on the nail plate of his right little finger. The streak extended from the nail root along the longitudinal axis of the nail plate. The patient also exhibited keratinized subungual hyperplasia under the distal nail margin, which progressed slowly and was associated with tenderness. Surgical excision was performed, and histopathological examination revealed papillomatous hyperplasia of the squamous epithelium with hyperkeratosis. Consequently, a diagnosis of onychopapilloma with longitudinal erythronychia presentation was established.