Symplastic glomus tumor: report of a challenging lesion with literature review.

Glomus tumors are uncommon mesenchymal tumors whose cells closely resemble those of a normal glomus body, and are found most commonly in the hand. Recently, a symplastic form exhibiting marked nuclear atypia, in the absence of any other malignant features, has been described. To date, only 14 cases of symplastic glomus tumor have been reported in the literature; hence, very little information is available about its diagnosis, treatment, and biological behavior. The case reported here concerns a symplastic glomus tumor occurring in the right index finger of a 62-year-old woman. We reviewed the literature concerning previously reported cases, placing emphasis on the documented biological behavior, treatment, and demographic trend. Physicians must be aware of this morphological variation of glomus tumor to avoid the mistake of malignancy, which results in over-treatment of the patient.