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Author: Dr Diana Purvis, Dermatologist, Starship Hospital, Auckland, New Zealand; Chief Editor: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, December 2016.
Onychopapilloma is a benign neoplasm of the nail matrix. It is usually an isolated lesion affecting one nail.
Onychopapiloma is rare. It can affect males and females of all races and ethnicities. It has mainly been described in middle-aged and older adults.
The cause of onychopapilloma is unknown.
Onychopapilloma usually results in a longitudinal streak in a red nail (erythronychia), which extends from the lunula to the tip of the nail.
The diagnosis may be suspected clinically, but as malignant lesions under the nail could look similar, it is important to keep the lesion under review and undertake nail biopsy if there is an enlarging lesion.
Histology of a nail clipping showing an area of asymmetrical dyskeratosis and papillomatosis.
Longitudinal biopsy of the nail shows a papillomatous nail bed with layers of hyperkeratosis and an absent granular layer. Pigmentation if present, is due to melanocyte activation.
The differential diagnosis for onychopapilloma includes:
Longitudinal excision of the entire affected nail and proximal nail matrix is curative.
Untreated, the lesion tends to persist.
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