Advanced MRI findings of supratentorial medulloblastoma recurrence in a young adult: a case report and literature review

Conventional contrasted magnetic resonance imaging (MRI) poorly differentiates medulloblastoma (MB) recurrence from radiation-induced tumors or radionecrosis. Herein, we demonstrate the usefulness of advanced diffusion-weighted-imaging (DWI) and perfusion-weighted imaging (PWI) MRI techniques for the diagnosis of supratentorial MB recurrence in a 27-yearold patient with leptomeningeal carcinomatosis and the subsequent appearance of two supratentorial intraaxial masses. Significant diffusion restriction with ADC values for the right lesion of 448 x 10-6 mm2/s and 492 x 10-6 mm2/s for the left lesion were found. These values were low compared with the healthy brain parenchyma of 707 x 10-6 mm2/s. The DSC-PWI analysis showed increased quantitatively measured relative cerebral blood volume (rCBV) with an rCBV index of 4.89 and 4.34 (right and left, respectively) compared with 1.05 of healthy white matter. Supratentorial MB recurrence was diagnosed in a patient with masses in the temporal poles based on DWI and PWI MRI sequences, typical of highly cellular tumors with blood-brain barrier alterations and increased angiogenesis. This case report is the first from Mexico that characterizes MB recurrence with advanced MRI techniques.