Primary central nervous system lymphoma with lateral ventricle involvement

A 77-year-old woman presented with worsening cognitive impairment, nausea and vomiting. Computed tomography (CT) of the head revealed a high-density mass that symmetrically filled both lateral ventricles. Magnetic resonance imaging (MRI) showed an enhanced mass with T1 and T2 prolongation and restricted diffusion on diffusion weighted imaging (DWI). Diagnosis was delayed until a post-mortem examination, which revealed the mass as a primary central nervous system lymphoma (PCNSL). A high-intensity tumor on DWI with lateral ventricle involvement should raise the possibility of PCNSL.