Glomus Tumor of the Kidney Harboring Malignant Potential

Glomus tumors are rare, benign, vascular neoplasms arising from the glomus body. Although they occasionally develop in any part of the body, they do so more common in the upper extremities, most frequently subungual areas. An extensive review of the literature revealed less than thirty cases of primary renal glomus tumors. We present a unique case of an adult male with an incidentally discovered 2.5 cm right renal mass. Histopathologic and immunohistochemical examination suggested the diagnosis of glomus tumor. Based on the World Health Organization (WHO) classification of soft tissue tumors, the presence of at least two atypical features indicates malignant potential. In this case, deep/visceral location and size greater than 2 cm fulfilled these criteria. Following an uneventful excision and a 12-month follow-up period, the patient remains disease-free with no sign of local or distant metastases.