Percheron Artery-Plus Syndrome: A Syndrome Beyond Stroke Chameleon

The artery of Percheron (AOP) is an anatomical variant of the thalamoperforating arteries. AOP occlusion can cause bilateral paramedian thalamic infarctions and is referred to as a "stroke chameleon" because it lacks the classic signs of stroke. Coexistence of AOP occlusion and other neurologic disease is rare and can cause disturbance of consciousness. A 78-year-old woman had acute onset of left limb weakness and drowsy consciousness. Brain magnetic resonance angiography (MRA) revealed acute bilateral paramedian thalamic infarctions. However, serum and cerebrospinal fluid (CSF) cryptococcal antigen titers were 1:16 and 1:128, respectively. The CSF culture grew Cryptococcus neoformans. Although consciousness and muscle power improved after treatment, the patient later died of pneumonia. A 68-year-old woman developed acute disturbance of consciousness followed by delirium. Brain MRA revealed acute bilateral paramedian thalamic infarctions. Elevated free thyroxine, anti-thyroperoxidase, and anti-thyroglobulin antibodies were detected. She received 3 days of steroid pulse therapy followed by oral prednisolone. Her consciousness gradually improved after Hashimoto encephalopathy and stroke were controlled. AOP occlusion was diagnosed early in these two patients. However, other concomitant life-threatening diseases could have been overlooked because of the complicated diagnostic determination. Further serum cryptococcal antigen, anti-TPO Ab, and anti-TG Ab surveys might help to exclude cryptococcal meningitis and Hashimoto encephalopathy. CSF study is warranted when central nervous system infection is strongly suspected. This "Percheron artery-plus syndrome" comprises multifaceted disorders beyond the stroke chameleon and requires attention.