Differential diagnosis of truly suprasellar space-occupying masses: synopsis of clinical findings, CT, and MRI

Abstract

This review demonstrates the features of truly suprasellar masses in modern imaging based on the clinical, CT, and MRI findings of 42 patients with suprasellar masses in correlation to the histologic findings. The radiologic examinations were evaluated retrospectively to determine if diagnosis can be made based on specific imaging patterns. The most frequent clinical findings of space-occupying suprasellar masses were visual disturbances, diabetes insipidus, and symptoms and signs of occlusive hydrocephalus. There were no clinical features specific for any of the observed masses. Craniopharyngiomas were the most frequent tumors. They appeared in two different forms, as cystic and as solid enhancing masses. The cystic tumors could not be differentiated from cystic hamartomas or cystic gliomas by CT or MRI. The solid craniopharyngiomas were similar to meningiomas and hamartomas. In craniopharyngiomas of adults calcifications were not common. In CT and especially in MRI gliomas were characterized by the diffuse infiltration of the adjacent brain tissue or optic nerve. Except for meningiomas, all lesions were highly variable in appearance, making a reliable characterization by CT and MRI difficult in many cases. However, administration of contrast media in some cases resulted in a better tumor delineation. Compared with unenhanced MRI the enhanced scans did not increase diagnostic efficacy for neoplasms, but were helpful in the differentiation from inflammatory diseases. The MRI technique was superior to CT in demonstrating the anatomic relationships, thus facilitating evaluation of origin and extent of the lesions. The CT technique, of course, was more reliable in the detection of calcifications. Both CT and MRI are not tissue-specific, however,and suprasellar tumors as well as many other neoplasms cannot be classified using only one of these imaging techniques.To optimize the diagnostic strategy both imaging modalities should be used with close regard to patient history, physical examination, and clinical parameters.