Haemangiopericytoma of the parotid gland. Report of a case and review of the literature.

A primary malignant haemangiopericytoma of the parotid gland is reported. Microscopically the tumour showed two different types of area: in the first a histologically benign haemangiopericytoma was present, in the second, separated from the former by a clear-cut border, the structure was that of a histologically malignant haemangiopericytoma which subsequently metastasized and killed the patient. The report stresses the great rarity of this neoplasm in the parotid gland and discusses the problem of the behaviour of haemangiopericytomas.