Glomus tumor.

Glomus tumor is a benign mesenchymal neoplasm comprising less than 2% of soft tissue tumors. It is composed of cells resembling modified smooth muscle cells of the normal glomus body. The glomus body, a thermoregulator, is a specialized form of arteriovenous anastomosis localized in dermal and precoccygeal soft tissue. Although glomus tumors are rare neoplasms, clinical misdiagnosis of many of these lesions as hemangiomas or venous malformations makes an accurate assessment of their actual prevalence difficult. A malignant counterpart of this lesion exists but is extremely rare.