High-altitude cerebral edema (HACE) is a rare condition of acute mountain sickness that manifests as consciousness disturbance and truncal ataxia. Neuroimaging shows vasogenic edema with microbleeds in the white matter and the corpus callosum. We herein report a case of HACE in which the patient showed widespread hyperintense signals with extensive microbleeds in the white matter and corpus callosum on MRI, as well as cognitive dysfunction. Rehabilitation to improve the higher brain function facilitated the recovery of the patient's cognitive impairment and was accompanied by improved MRI findings.

Highlights A patient exhibited IgG4-related hypothalamo-hypophysitis. Prominent high-signal areas of swelling were observed in the hypothalamus, tuber cinereum, infundibulum, and bilateral optic nerve systems. MRI T1WI with contrast media demonstrated enhanced neurohypophysis and cystic swelling, and compressed anterior pituitary. MRI findings improved rapidly after 4 days of steroid therapy.

Highlights An extremely rare case of bilateral cerebral peduncular infarctions (BCPI) is reported. The detection of the pure Mickey Mouse ears sign on MRI is an indicator of a need for reperfusion therapy. Severe stenosis of the basilar artery (BA) and a poor collateral supply from both posterior cerebral arteries were seen. Balloon angioplasty for the BA stenosis ameliorated the stenosis and produced a favorable outcome.