Metastasising canine fibrosarcoma originally diagnosed as haemangiopericytoma

Haemangiopericytoma of the left carpal joint region was diagnosed in a biopsy from a 13‐year‐old Cocker Spaniel. Six months later, there was recurrence at the original site with pulmonary metastases. Ultrastructural examination revealed that the neoplastic cells did not have an enveloping membrane. Since the finding of such membranes is characteristic of human pericyte tumours, the canine growth was classified as a fibrosarcoma. It is suggested to re‐evaluate the use of the term haemangiopericytoma in veterinary medicine.