Hemangiopericytomas are rare vascular tumors and one-thirds occurs in the head and neck. These tumors grow slowly and may easily be mistaken for a benign lesion. A twenty-nine-year-old man presented with a large mass on the left side of his neck. Palpation, ultrasonography, and magnetic resonance imaging findings were incorporated into a histopathologic diagnosis of malignant hemangiopericytoma. The tumor was subtotally excised following preoperative embolization of the branches of the subclavian artery and the left vertebral artery. The patient was submitted to radiotherapy. He has been under close follow-up for 16 months without any recurrences.