Pituitary adenoma, craniopharyngioma, and Rathke cleft cyst involving both intrasellar and suprasellar regions: differentiation using MRI.

AIMS: To determine the differential magnetic resonance imaging (MRI) features of pituitary adenoma, craniopharyngioma, and Rathke cleft cyst involving both intrasellar and suprasellar regions.

MATERIALS AND METHODS: The MRI images of 64 patients with pituitary adenoma (n=38), craniopharyngioma (n=13), or Rathke cleft cyst (n=13) were retrospectively reviewed by three neuroradiologists. The following characteristics were evaluated: shape, volume, extent, component characteristics, signal intensities of solid portions on T2-weighted images, signal intensities of cystic portions on T1-weighted images, and enhancement patterns of solid portions and cyst walls of tumours. Fisher's exact test applied with Bonferroni correction was used for multiple comparison. A flowchart for differential diagnosis was constructed based on statistical analysis of the results.

RESULTS: A snowman shape, solid characteristics, and homogeneous enhancement of the solid portion were more common in pituitary adenomas (p<0.017). A superiorly lobulated shape, third ventricle compression by superior tumour extension, mixed solid and cystic characteristics, and reticular enhancement of the solid portion were more common in craniopharyngiomas (p<0.017). Finally, an ovoid shape, a small tumour volume, cystic characteristics, and no or thin cyst wall enhancement were more common in Rathke cleft cysts (p<0.017). The flowchart yielded diagnostic accuracies as follows: 92.1% in pituitary adenoma; 92.3% in craniopharyngioma; 92.3% in Rathke cleft cyst; and 92.2% overall.

CONCLUSION: A combination of MRI findings is helpful in the differential diagnosis of the three tumours involving both intrasellar and suprasellar regions.