Scientific paper sessions

2009 Neuroradiology  
Neuroradiology (2009) 51 (Suppl 1):S25-S97 S27 PURPOSE Anaplastic medulloblastoma and medulloblastoma with extensive nodularity (MBEN) were added as new variants in the 2007 WHO classification of tumours of the central nervous system (CNS). The purpose of this retrospective multicenter study was to define the spectrum of MRI findings in MB variants and compare those with classic MB. MATERIALS AND METHODS MR examinations and clinical and pathology reports from 4 institutions, for a total of 28
more » ... tients with histologically proven diagnosis of MB, were retrospectively analyzed. The location, size, margins, signal intensities, enhancement pattern, hemorrhage, calcifications, edema, diffusion characteristics, and the presence of hydrocephalus were evaluated. RESULTS Twenty-eight patients, 16 male 12 female (mean age, 12.6 years) were included. Of the 28 tumors, 21 were located in the region of the 4th ventricle; 7 were found ;5/28 were MBEN; 6/28 were a desmoplastic/ nodular variant; and one was a large cell MB. Classic MB was predominantly hyperintense on T2WI (with intratumoral cysts), and hypointense on T1WI, with subtle (5/13) or marked but inhomogeneous enhancement. In MB-EN, cortex isointensity was present on T2WI, a low signal on T1WI with marked enhancement (a central scar-like pattern), and a multinodular appearance. Anaplastic MBs were hyperintense on T2WI with intense enhancement. All CMB and variants had restricted diffusion with low ADC values. Hemorrhage was seen in 4 patients with CM, and in one patient with large cell MB. Hydrocephalus was present in 20/28 patients. CONCLUSION The expanded histological spectrum, with the currently recognized 4 MB variants, showed overlapping MRI features for classic MB and MB variants. Certain MRI characteristics may favor MBEN and desmoplastic/nodular MB variants. Anaplastic and large cell MB did not show any distinctive imaging features.
doi:10.1007/s00234-009-0561-4 fatcat:o5kffdrey5e7pp6rpqpvepbowy