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Created page with "==Introduction== Haemangiopericytomas are '''very common mesenchymal tumours''' in '''middle-aged or older dogs'''. It is more common in '''large breed''' dogs but there is no se..."
==Introduction==
Haemangiopericytomas are '''very common mesenchymal tumours''' in '''middle-aged or older dogs'''. It is more common in '''large breed''' dogs but there is no sex predilection.
Such tumours occur rarely in cats.
The '''origin of these tumours is uncertain''', although they seem to be associated with the periphery of blood vessels and they may be related to Peripheral Nerve Sheath Tumours.
==Clinical signs==
Tumours are usually '''solitary''', arise in the subcutis '''around joints of limbs''', and are multilobulated and '''inflitrative'''.
Their gross appearance varies, from white/gray to red, and rubbery to fatty.
==Diagnosis==
'''Fine Needle Aspiration''' should be performed.
Characteristic cytological features include: '''perivascular whorls of fusiform cells'''. Cells may also be arranged in interlacing bundles. In some tumours there is a patchy mucinous matrix.
The tumour may be well demarcated from adjacent structures, but it often '''invades along fascial planes''' leading to recurrences.
The mitotic index is the key '''prognostic indicator''' in these tumours, and the usually low metastatic potential increases with each recurrence.
It can be difficult to distinguish these tumours from '''Peripheral Nerve Sheath Tumours'''.
'''FNA of the draining lymph node''' may also be performed to stage the tumour.
==Treatment==
'''Aggressive initial surgery''' is the best treatment for haemangiopericytomas. Wide margins may be difficult to obtain due to the location on limbs. '''Recurrence''' following surgery is common.
'''Radiotherapy''' can also result in tumour control and longer survival times. '''Amputation''' may also have to be considered.
Chemotherapy is not effective.
==References==
Meuten, D. (2002) '''Tumors in Domestic Animals''' ''Wiley-Blackwell''
Freeman, K. (2007) '''Self-assessment colour review of: Veterinary cytology''' ''Manson Publishing''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]
Haemangiopericytomas are '''very common mesenchymal tumours''' in '''middle-aged or older dogs'''. It is more common in '''large breed''' dogs but there is no sex predilection.
Such tumours occur rarely in cats.
The '''origin of these tumours is uncertain''', although they seem to be associated with the periphery of blood vessels and they may be related to Peripheral Nerve Sheath Tumours.
==Clinical signs==
Tumours are usually '''solitary''', arise in the subcutis '''around joints of limbs''', and are multilobulated and '''inflitrative'''.
Their gross appearance varies, from white/gray to red, and rubbery to fatty.
==Diagnosis==
'''Fine Needle Aspiration''' should be performed.
Characteristic cytological features include: '''perivascular whorls of fusiform cells'''. Cells may also be arranged in interlacing bundles. In some tumours there is a patchy mucinous matrix.
The tumour may be well demarcated from adjacent structures, but it often '''invades along fascial planes''' leading to recurrences.
The mitotic index is the key '''prognostic indicator''' in these tumours, and the usually low metastatic potential increases with each recurrence.
It can be difficult to distinguish these tumours from '''Peripheral Nerve Sheath Tumours'''.
'''FNA of the draining lymph node''' may also be performed to stage the tumour.
==Treatment==
'''Aggressive initial surgery''' is the best treatment for haemangiopericytomas. Wide margins may be difficult to obtain due to the location on limbs. '''Recurrence''' following surgery is common.
'''Radiotherapy''' can also result in tumour control and longer survival times. '''Amputation''' may also have to be considered.
Chemotherapy is not effective.
==References==
Meuten, D. (2002) '''Tumors in Domestic Animals''' ''Wiley-Blackwell''
Freeman, K. (2007) '''Self-assessment colour review of: Veterinary cytology''' ''Manson Publishing''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]