We report a case of large-size pelvic hemangiopericytoma (HPC) incidentally discovered in a 32-year-old woman. Prior to surgery the patient was studied using a CT scan and magnetic resonance imaging (MRI). Because of the size and scarce extent of the tumour (it expanded downwards, into the right ischiorectal fossa) a combined abdomino-perineal approach was needed for complete resection. Seventy-two months after initial surgery the patient remains asymptomatic, with no signs of local recurrence or distant metastasis.