MRI-Based Classification of Rathke’s Cleft Cyst and Its Clinical Implication

Abstract

Background Rathke’s cleft cysts (RCCs) are benign tumors of the pituitary gland. Small, asymp-tomatic RCCs do not require surgical treatment, whereas surgical treatment is required for symptomatic RCCs. Methods We retrospectively reviewed medical records of patients with an RCC who were diagnosed and managed in our institution between April 2004 and April 2020 and generated two different cohorts: the observation (n=114) and the surgical group (n=99). Their initial MRI signal characteristics were analyzed. The natural course focusing on cyst size was observed in the observation group and postoperative visual and endocrine outcomes were evaluated in the surgical group. Results The characterization of MRI signals of cyst contents in both T1-weighted (T1W) and T2-weighted (T2W) images revealed nine combinations for our 213 patients. Among 115 patients with a high T2W signal, the cysts showed hypo-, iso-, and hyper-intensity on T1W images in 72, 39, and 44 patients, respectively; Type S-low, Type S-iso, and Type S-high. One more major group of 35 patients showed RCCs with hyperintensity on the T1W images and hypointensity on the T2W images named as Type M. In the comparison between observation and surgical groups, we identified only two major groups in which the number of patients in the surgical and observation groups was statistically differ-ent: more Type S-low in a surgical group (p<0.001) and more Type M in an observation group (p=0.007). In subgroup analysis, the range of change in the cyst size was the highest in Type S-high in the observation group (p=0.028), and intergroup differences in visual and endocrine outcomes were not evident in the surgical group. Conclusion MRI characteristics help to predict the natural course of RCCs. We identified sub-groups of RCCs which are more or less likely to require surgical intervention.