Extradigital glomus tumor: A case report.

A glomus tumor is a benign vascular tumor derived from the modified smooth muscle cells of the glomus body. The lesions develop as small blue-red nodules that are usually located in the deep dermis or subcutis of the upper or lower extremity. The single most common site is the subungual region of the finger, but other common sites include the palm, wrist, forearm and foot. In the present study, we report the case of a 45-year-old patient diagnosed with extradigital glomus tumor of subcutaneous tissue of elbow. Histopathological examination revealed that the tumor was a well-circumscribed nodule with focal invagination of tumor cells into the adjacent upper dermis. The tumor was composed of solid sheets of cells interrupted by vessels of varying size. Immunohistochemically, the tumor cells were reactive for smooth muscle actin (SMA) and vimentin (VMT). The majority of glomus tumors may be treated adequately by the correct diagnosis and simple excision. However, extradigital glomus tumors are occasionally difficult to diagnose owing to their non-specific clinical characteristics, including unusual sites and symptoms which vary compared with those of classical glomus tumors. Therefore, it is crucial to include glomus tumors in a differential diagnosis of patients with extradigital lesions.