A glomus tumor is benign neoplasm that originates from cells of the glomus body. Glomus bodies are highly concentrated in the fingertips, so not surprisingly, glomus tumors are most common in the hands and subungual region. Small single tumors are most frequent, and women are affected more often than men. Most patients are between 30 and 50 years of age. Subungual glomus tumors may present with a triad: pain, pinpoint tenderness, and cold sensitivity. Physical examination may show a small reddish or bluish papule several millimeters in diameter. Some may present as a longitudinal erythronychia with distal notching or overlying longitudinal fissure.

There is a familial variant of glomus tumor, linked to chromosome 1p21–22, encoding the glomulin gene (GLMN). Multiple glomus tumors are inherited as an autosomal dominant trait and are usually found on the legs. They are often present in younger children. Neurofibromatosis type 1 may present with numerous glomus tumors involving the digits. They are often painless.