Transient Global Amnesia in a Patient with Pituitary Adenoma: Causal or Chance Association?

A 65-year-old man with no underlying medical history visited the neurology department due to transient amnesia lasting for about 8 h. During the amnesia episode, he was alert but showed repetitive questioning. The episode fulfilled the diagnostic criteria for transient global amnesia (TGA). On workups for excluding alternative diagnoses, the brain magnetic resonance imaging revealed a 3 × 6 cm-sized hemorrhagic pituitary tumor extending to the left medial temporal lobe and anterior hippocampus. The electroencephalogram revealed intermittent slowing in the left temporal region with normal backgrounds. The tumor was surgically removed and pathologically proven to be a nonfunctioning adenoma. At 6 months postoperatively, no complication or new amnestic episode occurred. Thus, our case had a typical TGA as the first manifestation of a pituitary tumor. There were no features of epileptic amnesia. Transiently altered flow status from a mass effect in the memory-eloquent area might be the possible pathogenic mechanism underlying the TGA though there still remains a probability of chance concurrence of TGA and tumor.