Imaging of Rathke's Cleft Cysts: Criteria for a Differential Diagnosis

Rathke's cleft cysts are a congenital disorder of the pituitary gland and derive from abnormalities of the development of the adenohypophisis. The variability of the MRI signal of Rathke's cleft cyst hampers the differential diagnosis with the other cystic lesions of the pituitary gland. Nevertheless a comparison between the various findings reported from by author we reviewed indicates that a description of useful criteria for a differential diagnosis is possible. We suggest that the mean age at onset, the symptoms, the magnetic signal intensity, the location within the gland, the relations with the surrounding structures and the behaviour after contrast injection should always be considered in the diagnostic work-up of Rathke 's cleft cysts. There is no consensus in the literature on the correct therapeutic protocol. We suggest following up a small asymptomatic Rathke's cleft cyst (except mucoid cysts) because they do not generally enlarge. Surgery is instead the gold standard for symptomatic Rathke's cleft cysts, large Rathke's cleft cysts and mucoid Rathke's cleft cysts. Mucoid Rathke's cleft cysts, even when small, may cause an intense pituitary inflammation which could lead to irreversible endocrine dysfunction.