Magnetic resonance imaging (MRI) of the brain. (A) T1-post-gadolinium sequence with no enhancement. (B) T2-fluid-attenuated inversion recovery (FLAIR) sequence with hyperintensities in both mesial temporal lobes (arrow). (C) Diffusion-weighted images with T2 shine-through in the right temporal lobe and hippocampus (arrow). (D) Chest X-ray with right lower lobe infiltrates consistent with post-obstructive pneumonia (long arrow), complete opacity of the right middle and upper lobes due to atelectasis from small-cell lung cancer (short arrows). (E) Chest computed tomography scan with contrast of mediastinal and hilar lymphadenopathy (short arrows) and a loculated right lower lobe pleural effusion (long arrows). (F) MRI of the brain 6 months after initial neurological presentation with temporal horn enlargement (short arrow), hippocampal atrophy (long arrow) and resolution of T2-FLAIR hyperintensities.