The purposes of this study were to estimate the prevalence of Rathke cleft cysts (RCC) in a pediatric population on brain MRI, to describe their appearance, and to estimate interobserver agreement in the detection of RCC.

The brain MRI examinations of 460 children were retrospectively reviewed by two radiologists for the presence of RCC. There were 223 boys and 237 girls with a mean age of 8.8±4.3 (standard deviation [SD]) years (range: 0.1–14.9 years). When present, RCC were analyzed with respect to internal contain and further classified as serous RCC (i.e., high signal on T2-weighted sequences and iso or low signal on T1-weighted sequences) or mucosal RCC (i.e., low signal on T2-weighted sequences and high or iso signal on T1-weighted sequences). Cohen's Kappa coefficient was used to estimate interobserver agreement between the interpretations performed by the two radiologists for the presence of RCC.

A total of 14 children had a RCC present on brain MRI, yielding a prevalence of 3.04% (14/460); of these, 3/14 RCCs (21%) were of serous type and 11/14 (79%) were of mucosal type. Interobserver agreement for the presence of RCC was strong (Kappa=0.85; 95% CI: 0.70; 0.99).

The results of our study suggest that the prevalence of RCC in children is greater than previously described.