This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Onychocytic matricoma is a rare tumor of the nail that is generally benign. Affected people often experience thickening of the involved portion of the nail. The tumor may be pigmented (melanonychia – a black or brown pigmentation of the normal nail plate) or non-pigmented. The exact underlying cause of onychocytic matricoma is currently unknown. It generally occurs sporadically in people with no family history of the condition. Treatment generally consists of surgical excision.
For more information, visit GARD.