Nail biopsy. Indications and methods.

Nail biopsy is a safe and useful diagnostic procedure for many nail disorders when routine clinical and laboratory methods fail to produce a diagnosis. Prerequisites for nail biopsy are an understanding of the surgical anatomy of the nail, adequate anesthesia and hemostasis, and a nail abnormality for which histopathology can provide the diagnosis. Indications and methods for nail biopsy vary according to the site and type of pathology in the nail unit. Nail bed and perionychial biopsies can be performed easily and with minimal scarring. They are most commonly used to diagnose tumors as well as infectious and inflammatory disorders of the nail. The most important reason to biopsy the nail matrix is to make or exclude the diagnosis of melanoma in a patient with longitudinal melanonychia. Great care must be taken in nail matrix biopsy to minimize the risk of permanent nail dystrophy.