Onychoheterotopia: pathogenesis, presentation, and management of ectopic nail

Abstract

Background: Onychoheterotopia is an extremely rare condition in which the nail tissue grows outside the classic nail unit of the dorsal fingers and toes. It presents as either small outgrowths of a deviant nail or a complete double fingernail malformation. The histology of the onychoheterotopia matrix is oftentimes very similar to the normal nail matrix, although it plays a central role in diagnosis.

Objective: We sought to review the current literature on the clinical and histologic aspects of onychoheterotopia.

Methods: A literature search was performed to evaluate peer-reviewed articles on the topic.

Results: Detailed reports have characterized many features of onychoheterotopia. The various etiology and treatment options are reviewed.

Limitations: The study was limited to those articles in the English-language literature.

Conclusions: In this article, we provide a review of the literature based on the current understanding of onychoheterotopia, its diagnosis, and its management.