Hemangiopericytoma of the oral cavity after a ten-year follow-up.

Hemangiopericytoma (HPC) is a mesenchymal tumour that may be benign, malignant, or occur in an intermediate form. We report an unusual case of hemangiopericytoma located in the buccal mucosal region. The histopathologic features showed increased cellularity, necrosis, hemorrhage, low proliferation index, and 4 or less mitotic figures per 10 high-power fields. Since this histological pattern suggests an intermediate form characterized by unpredictable clinical behavior, life-long follow-up is essential. In this patient no recurrences or distant metastases were evident at 10-yr follow-up.