Rathke's cleft cyst: clinicopathological and MRI findings in 22 patients.

AIM To evaluate clinical findings and magnetic resonance imaging (MRI) characteristics of Rathke's cleft cyst (RCC) in 22 patients. MATERIALS AND METHODS Twenty-two patients were imaged using non-enhanced MRI and 17 underwent an additional contrast-enhanced MRI examination. Fifteen patients received an additional non-enhanced computed tomography (CT) examination, and amongst these, two underwent contrast-enhanced CT. Two radiologists read the images retrospectively. The imaging data were studied with regards to location, size, margin, signal intensity, enhancement characteristics, haemorrhage, and presence of calcifications. Clinical data, such as presenting signs and symptoms, physical findings, and medical histories, were collected. Histopathological studies were performed and analysed by two pathologists. RESULTS Nine lesions were located in the intrasellar region, 12 in both the intra- and suprasellar regions and one in the suprasellar region. The maximum diameter of the RCCs varied from 0.7 to 4 cm, with an average size of 1.7+/-0.7 cm. MRI features of RCC were divided into three groups based on T1-weighted imaging (T1WI): hypo- (n=6), iso- (n=9), and hyperintensity group (n=7). Patients in the latter two groups were statistically younger than that in the former group. The lesion size in the iso- and hyperintensity groups was significantly less than that in the hypointensity group (F=6.421, p=0.007). Only two cases showed enhancement after contrast injection in the cohort. One lesion with haemorrhage was found as were two cases with intracystic nodules. CONCLUSION Although MRI features of RCCs are variable, RCCs should be suspected when the following conditions occur: lesions located in the intrasellar region or involving both intra and suprasellar regions, less than 1.5 cm in diameter, iso- or hyperdense on T1WI and no signal enhancement after contrast injection. In addition, the first case of a RCC with a markedly enhanced intracystic nodule is reported.