Radiologic assessment of pituitary microadenomas.

Radiographs of 146 patients who had a pituitary adenoma removed by the transsphenoidal approach were reviewed. The area and volume of the sella were measured in all the patients. In 73 patients the sella had a normal size and appearance as shown on routine lateral and frontal radiographs. However, thin-section tomograms of the sella in these patients demonstrated findings indicative of an intrasellar mass in all but three instances. The diagnosis of pituitary microadenoma (adenoma less than 1.5 cm in diameter) may, therefore, be missed if only plain skull radiographs are used to assess the sella. No correlation could be shown between the location of the sellar changes seen using thin-section tomography and the histologic type of pituitary adenoma.