The glomus tumor is a benign malformation of the glomus corpuscle. Glomus corpuscles serve to regulate the skin temperature on the hands and are mainly located under the nails. Five and seventy percent of glomus tumors occur in the hand under the fingernails. Glomus tumors make up only one percent of all hand tumors. They are more common in women between the ages of thirty and fifty and occur spontaneously. Glomus tumors typically manifest themselves through pain that is limited in places and sensitivity to cold. Discoloration of the nail bed is visible under the nail. Occasionally, nail deformations also occur.