Chiasmal apoplexy due to hemorrhage from a pituitary adenoma into the optic chiasm: case report

Chiasmal apoplexy, defined as hemorrhage into the optic chiasm, generally is caused by an intrachiasmal vascular malformation. We report the first case of chiasmal apoplexy due to hemorrhage from a pituitary macroadenoma into the optic chiasm. A 52-year-old man presented with headache, sudden and severe deterioration of visual acuity in the left eye, and a bitemporal visual field deficit. Magnetic resonance imaging revealed a large intra- and suprasellar homogeneously enhancing mass, which elevated a markedly thickened optic chiasm. After emergent transsphenoidal resection of the pituitary adenoma, vision did not improve. A pterional craniotomy was subsequently performed, during which a hematoma was found and evacuated from within the substance of the left optic nerve and chiasm. The hematoma cavity was found to communicate with the sella through a defect in the diaphragm. Vision improved dramatically after the operation. Chiasmal apoplexy resulting from pituitary adenoma should be distinguished from pituitary apoplexy, particularly because it requires a different surgical treatment. Clinical and radiographic features that may help distinguish the two are discussed.