Macrocerebellum, also known as cerebellar hyperplasia, refers to a rare condition characterised by an abnormally enlarged cerebellum with preserved architecture and shape. It is usually demonstrated on imaging with a thickening of the cortical grey matter of the cerebellar hemispheres.
Macrocerebellum is a rare imaging finding, only a few case have been reported 3.
It is usually dependent on the underlying disease. Hypotonia, ataxia, and ocular movement disorders are related in patients with an isolated macrocerebellum 1,2.
The aetiology is unknown. For some authors, it is not considered as an independent entity, but a manifestation of different conditions 2,3. For others, it is a cerebellar response to the elaboration of growth factors intended to augment the slow development of cerebral structures 1.
It can be found as an isolated (non-syndromic) condition or as part of a well-defined syndrome, such as Costello syndrome and Sotos syndrome, or neurometabolic diseases (e.g. mucopolysaccharidosis type I and II) 2.
There is no malformation, only a diffusely enlarged cerebellum, especially due to cerebellar hemispheres cortical grey matter 2,3.
- 1. Bodensteiner JB, Schaefer GB, Keller GM et-al. Macrocerebellum: neuroimaging and clinical features of a newly recognized condition. J. Child Neurol. 1997;12 (6): 365-8. Pubmed citation
- 2. Bosemani T, Orman G, Boltshauser E et-al. Congenital abnormalities of the posterior fossa. Radiographics. 2015;35 (1): 200-20. doi:10.1148/rg.351140038 - Pubmed citation
- 3. Poretti A, Mall V, Smitka M et-al. Macrocerebellum: significance and pathogenic considerations. Cerebellum. 2012;11 (4): 1026-36. doi:10.1007/s12311-012-0379-1 - Pubmed citation