[Chiasmal radionecrosis after irradiation of the sella turcica using a conventional dosage. Contribution of magnetic resonance imaging].

A 47 year-old man developed rapid visual loss, visual field defects and memory disturbances after radiotherapy with conventional doses for a pituitary metastasis from a renal carcinoma. CT and MRI did not show recurrent tumour, pituitary apoplexy or empty sella. Eventually, T2-weighted MRI images showed abnormal high signals in the optic chiasm, the left mesial temporal lobe and the right inferior frontal lobe, supporting the diagnosis of delayed radionecrosis. The role of chemotherapy associated with radiotherapy is discussed.