Presentation
18 month old. Signs of truncal ataxia.
Patient Data
Gross asymmetry of the cerebellar hemispheres.
Markedly thickened folia in the right cerebellar hemisphere, causing mass effect on the vermis, brainstem and pons, with an element of cerebellar tonsillar descent. The thickened folia enhance and have low ADC values.
Displacement and compression of the 4th ventricle with a resultant severe biventricular hydrocephalus.
Transependymal edema.
Multiseptated cystic component on the medial aspect.
Right posterior fossa craniectomy.
Resection of the right cerebeller mass. No recurrent or residual disease.
Case Discussion
This case was initially thought to represent Lhermitte-Duclos disease (LDD) also termed dysplastic cerebellar gangliocytoma, is a rare tumor of cerebellum. Multiple radiologists with varying degrees of sub-speciality on 3 continents thought this is the most likely diagnosis.
In Lhermitte-Duclos the abnormal tissue involves the cerebellar cortex, and is usually confined to one hemisphere. It can atypically, as in this case, have a cystic component. Enhancement is not a typically a feature, although in the case mild enhancement is present. The dysplastic ''mass'' grows slowly with patient presentation usually related to the symptomatology resulting from obstructive hydrocephalus. The extent of the mass varies, with this case being particularly profound such the degree of the resultant mass effect.
The chief differential for the appearances in this age group is an atypical medulloblastoma - one with extensive nodularity.2
Surgical resection was undertaken, at which time the surgeon stated it didnt seem at all like a medulloblastoma.
It was histopathological confirmation was of a medulloblastoma.
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