Artery of Percheron infarct: a diagnostic challenge.

The artery of Percheron is a rare anatomical variation that supplies thalamus and the midbrain. A stroke in this area is a rare event. The presentation varies widely, with some bizarre disturbances, like transient episodic loss of consciousness similar to coma, somnolence, cognition and memory impairment and psychosis. We report a case of a patient who presented at the emergency department with a sudden change of consciousness. During the observation, she oscillated reactive state of consciousness with obnubilation similar to coma. The first exams were normal, which include a cranial CT of the brain, and so the patient was kept under observation. The final diagnosis was only possible 24 hours later with cranial CT where an ischaemic lesion on the Percheron territory was identified. This case highlights an unusual clinic and a difficult neuroimaging stroke diagnosis of a rare condition, that is unknown to most of the physicians.