Vertical triband flag sign for differential diagnosis of Rathke's cleft cyst.

Background:The Rathke cleft cyst (RCC) is a type of cystic growth that is benign, circular, and well-defined with an incidence rate of 4 %. This study aims to identify a useful diagnostic imaging sign that can aid in the differentiation of RCC from other cystic lesions. Methods:We retrospectively analyzed the records of 42 symptomatic RCC patients who were referred to our facility between 2016 and 2023. The data for the study were obtained from our electronic database. All magnetic resonance imaging (MRI) studies were performed using a 1.5-T superconducting magnetic scanner. All patients underwent endonasal transsphenoidal surgical resection. All MRIs were reviewed and evaluated by a neurosurgeon and a neuroradiologist. Results:There were 8 (19 %) males and 34 (81 %) females with a mean age of 37.2-years. Our study identified a distinct imaging characteristic in 38 of the cases, which we have named the "vertical triband flag sign", due to the growth of the cyst developing a specific appearance. The flag sign was mostly observed only in the T1-images (71.5 %), while in four cases the sign was spotted only in T2-images, and in four cases it appeared in both T1 and T2. In 4 cases, the flag sign was not observed in which further investigations revealed that these cases were suprasellar or small sellar RCCs. The dot sign, which is a characteristic finding in RCCs was only observed in one of our cases. Conclusion:Early diagnosis of RCCs may be facilitated by utilizing the vertical triband flag sign.