Onychopapilloma: its clinical, dermoscopic and pathologic features.

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Onychopapilloma is a rare benign tumor of the nail bed and distal matrix.
• It typically manifests as longitudinal erythronychia, leukonychia, or melanonychia.
• Limited data exists on Asian onychopapilloma characteristics.

Purpose of the Study:

• To investigate the clinical, dermoscopic, and pathological findings of onychopapilloma in Korea.
• To compare Asian findings with existing literature.

Main Methods:

• Retrospective review of 39 patients diagnosed with onychopapilloma from 2010-2021.
• Analysis of medical records, clinical, and dermoscopic photographs.
• Pathological examination of surgical excisions from 18 patients.

Main Results:

• The study included 39 patients (59% male), with a mean age of 46.1 years.
• Lesions were predominantly on fingers (92.3%), especially the thumb (66.7%).
• Longitudinal erythronychia (56.4%) and distal subungual hyperkeratosis (100%) were most common; macrolunula and trailing lunula identified as new dermoscopic features.

Conclusions:

• Asian onychopapilloma shares clinicodermoscopic similarities with Caucasian cases.
• Longitudinal erythronychia and distal subungual hyperkeratosis are key features.
• Macrolunula and trailing lunula are proposed as novel dermoscopic findings for onychopapilloma.