NeuroradiologyHaemangiopericytoma
tumour of "uncertain origin" in the WHO classification. It is considered by some authors as an angioblastic subtype of
meningioma. However, it derives from pericytes (that are modified smooth muscle cells) that surround
capillaries and not from meningothelial cells, and for this reason it should preferably be considered as a distinct mesenchymal
neoplasm.
Haemangiopericytoma is a rare tumour of adults. Haemangiopericytomas behave different from meningiomas since they have a tendency to bleed, to recur locally after surgery and to metastatize.
Angiography demonstrates extensive and prolonged tumour stain. Blood supply from pialdural arteries is typical. On CT and MR signs of extradural tumour location are not consistently present.
MR is the preferred imaging procedure. The tumour has a heterogeneous signal in all pulse sequences due to the presence of cystic, necrotic and haemorrhagic areas. Basically it is variably iso-hyperintense on T1-weighted and hyperintense on T2-weighted images. Strong but heterogeneous enhancement occurs after contrast injection. Intratumoral vessels can be identified. Brain oedema may be extensive.
NC