Myxoid Onychomatricoma—A New Case

Abstract

Onychomatricoma is a slow-growing, benign neoplasm of the nail matrix with several histological variants. With only 2 cases previously reported, the term “myxoid onychomatricoma” has been used by some authors to describe a rare variant, known to have a fibromixoid component. We present a case of a 51-year-old Caucasian woman with a 1-year history of thickening and discoloration of the right thumbnail, who was initially misdiagnosed as onychomycosis. After performing a magnetic resonance imaging that showed a tumor with several filamentous projections, an onychomatricoma was suspected and a total distal plaque avulsion was performed. Histology revealed a biphasic tumor with an epithelial component and a prominent myxoid stroma. Immunohistochemical staining was then used, confirming the diagnosis. Considering these findings, we believe that our case meets the diagnostic description of “myxoid onychomatricoma” and is, therefore, a new case of this rare histological variant.

Basic Concepts in Nail Pathology

“…61 Unlike the pleomorphic cells that are seen distributed diffusely in the superficial fibroblastic tumor, in onychomatricoma, they appear restricted to the most superficial stroma of the tumor. 60,62 Among the many variants of onychomatricoma are the myxoid, 63,64 the micropapiliferum, 65 the pigmented, 66 the pleomorphic, 61 or the giant. 67 Recently, a variant of proliferating onychomatricoma has been described.…”

“…Among the many variants of onychomatricoma are the myxoid, 63,64 the micropapiliferum, 65 the pigmented, 66 the pleomorphic, 61 or the giant. 67 Recently, a variant of proliferating onychomatricoma has been described.…”