Glomus tumor: Blood vessels (big arrow) surrounded by solid proliferation of round to cuboidal glomus cells with perfectly round

nuclei and acidophilic cytoplasm (small arrow).

Glomangiomablood vessels predominate.

Glomangioma: typical small, round glomus cells, often distributed in a monolayer or

bilayer around the vessel walls.

Glomus Tumor: Immunohistochemistry for smooth muscle actin showing diffuse

cytoplasmic positivity

Glomus tumor obvious intraoperatively