Subungual myxoid cysts: clinical manifestations and response to therapy.

Abstract

Myxoid cysts located beneath the nail are very different from those within the nailfold and there is no established literature on their diagnosis and therapy. Thirty-five cases of subungual myxoid cyst are described in which the diagnosis was confirmed by magnetic resonance imaging, surgical exploration, or both. The clinical characteristics of all cases of subungual myxoid cysts confirmed in 3 specialist nail clinics are reported. Twenty cases were confirmed by magnetic resonance imaging. Histologic details were recorded in 4 cases. Thirty-four patients (22 female, 12 male) presented with a subungual tumor of the thumb (n = 25) or finger (n = 10). The 3 main clinical variables were color of the lunula, transverse nail curvature, and integrity of the nail. In 26 cases the lunula was discolored; it was red in 22 cases, blue in 3, and as part of a longitudinal leukonychia in one. Transverse curvature was increased in 29 cases and was normal in 5 cases; in one case the nail was destroyed. In 11 cases, the change in curvature led to lateral ingrowing. Surgery (n = 22), sclerosant (n = 1), and spontaneous discharge (n = 2) all resulted in resolution. Ten patients had no treatment. This study describes 35 subungual myxoid cysts having characteristic features that allow clinical diagnosis. They respond to a range of treatments.