[Hemangiopericytoma of the posterior fossa: case report].

Hemangiopericytoma is an uncommon mesenchymal neoplasm arising from Zimmerman's pericytes, which usually locates in soft tissues. Meningeal hemangiopericytoma accounts for less than 1% of all intracranial tumours. Typically, it behaves aggressively, showing distinct tendency to recur locally or distantly along the neural axis and to present extraneural metastases. We describe a 74-year-old patient who presented unspecific symptoms and whose physical exam revealed a painless retroauricular mass which was adhered to skin. Neuroimaging studies showed a large posterior fossa tumour with intense enhancement after contrast infusion that caused striking occipital-mastoid osteolysis and which was exclusively fed by external carotid artery branches. The patient underwent gross total resection of the tumour, and once the histological diagnosis of hemangiopericytoma was confirmed, she underwent initial adjuvant radiotherapy. Sixteen months after surgery, the patient remains recurrence free. The treatment of choice of intracranial hemangiopericytoma is gross total resection, which must be attempted when technically feasible, followed by adjuvant radiotherapy providing total doses over 50 Gy. This combination has demonstrated increasing recurrence- free interval in these patients. Close and longterm follow-up is mandatory in order to achieve early diagnosis of recurrence or metastases in these patients, since they can appear several years, even decades, after initial proper treatment.