MRI and CT in a case of pituitary abscess.

We report the case of a woman admitted for hypopituitarism of sudden onset, in whom conventional radiography, CT and MRT suggested a pituitary tumour with supra- and intrasellar extensions. The surgical findings and the clinical course under antibiotic therapy transformed this diagnosis into one of pituitary abscess by a pyogenic micro-organism. Pituitary abscess is an exceptional lesion. Despite the advent of CT and MRI, its preoperative diagnosis remains difficult. However, the presence of an intrasellar expansive process with liquid centre and contrast-enhanced outline should suggest the possibility of an abscess, particularly when the pituitary lesion is associated with a sphenoidal sinus effusion.