Reported in this paper is the case of a woman, 43 years of age, with malignant haemangiopericytoma. The patient had undergone radical surgery and irradiation, following diagnosis of globucellular sarcoma. Metastasis occurred after an interval of six years from surgery. Histological checks revealed a pattern typical of haemangiopericytoma. The patient died one year later. - Morphology, incidence, clinical aspects, and general importance of this rare tumour are discussed against the background of relevant literature. The point is made that histological diagnosis may be quite difficult and that there is only limited possibility to draw conclusions from the morphological pattern of the tumour as to its biological importance.