Aim: Cerebral cavernous malformations (CCMs) are defined as a mulberry like assembly of thin-walled vascular sinusoids lined by a thin endothelium lacking smooth muscle and elastin, displaying no intervening brain parenchyma. In this study we analyse the congruency of histopathological features with the current clinical definition on a large series of neuroradiologically verified CCMs.
Methods: 87 patients without primary treatment prior to surgery were included. Preoperative MRIs of all patients were reviewed. Twelve histopathological parameters were assessed systematically, using HE, Prussian blue, elastica van Gieson and congo red for amyloid detection.
Results: 71/87 (81.6%) of the cases fulfilled the basic histological criteria of CCMs. Still, the thickness of vessel walls and the calibre of malformed vessels were highly variable. 16/87 cases (18.4%) were histologically non diagnostic. Non diagnostic specimens significantly associated with radiological signs of hemorrhages (p=0.001). A few cases (4.6%) regionally contained capillary-like malformed vessels. Intervening brain parenchyma between malformed vessels throughout the lesion was seen in 50/71 (70.4%) diagnosable lesions. Hemosiderin deposits, gliosis, thrombosis, fibrotic changes, hyalinized vessel walls, calcification and cholesterol crystals were present in a considerable range. In addition, we show amyloid deposits in 14/87 (16.1%) specimens.
Conclusion: In dis-congruency with the current clinical definition the absence of intervening brain parenchyma does not represent an essential histopathological criterion of CCMs in our series. Further, the diameter of the vessel lumina and the thickness of vessel walls vary considerably. Based on these findings, adaptation of the current definition on basis of interdisciplinary interaction needs to be considered.
- cerebral cavernous malformation
- intervening brain parenchyma