Glomus tumor with malignant features: A case report and review of the literature.

Glomus tumors are rare mesenchymal neoplasms of the subcutaneous tissue, most frequently found in the distal extremities. They are typically benign, but malignant glomus tumors have been described in the literature. Here we present a patient found to have a unilateral renal mass with pathology displaying a primary renal glomus tumor with malignant features. Review of the literature reveals only three cases of malignant glomus tumors and five glomus tumors with malignant potential. As such, previous initial presentations, current criteria for glomus tumor malignancy, and previous treatment outcomes of these cases were reviewed.