Ectopic Rathke's Cleft Cysts: Review of an Unusual Entity

Introduction: Rathke's cleft cysts (RCCs) are benign intracranial cysts typically found in the sella turcica or in the suprasellar space. Ectopic RCCs are rare but have been found in a variety of locations with varying presentations, interventions, and outcomes. As of yet, an RCC has not been identified in the anterior cranial fossa, specifically along the olfactory groove. We report the first case of histologically confirmed RCC in the anterior skull base and present a review of all reported ectopic RCCs identified in the literature.

Fig. 1

Methods: A complete review of the available literature was performed along with evaluation of reference lists of included articles to identify all case reports of ectopic Rathke's cleft cysts. The current case report of olfactory groove RCC was included for a total of eight cases. Data points including demographics, characteristics of the lesion, radiographic evaluation, intervention, and outcomes were collected and analyzed.

Results: There were three pediatric cases (37.5%) and five adult cases reported with a median age of 41 years. Two of the eight case reports were male patients (25%). The locations identified were left olfactory groove (one), upper half of the prepontine cistern (two), cerebellopontine angle (two), sphenoid sinus (two), and temporo-frontal-parietal region (one). Seven of the eight patients presented with headache (87.5%) with headache being the only presenting symptom in 25%. The second most common presenting symptoms were vertigo, nausea, and vomiting all present in two patients. The MRI features of the lesions were widely variable with relation to intensity on T1 and T2 series. In all cases, gross total resection was achieved of the primary lesions. In all cases where clinical outcomes were reported (87.5%), there was complete resolution of presenting symptoms. Histopathological evaluation was universally consistent with RCCs.

Table 1 Demographics of the studies

Conclusion: Rathke's cleft cysts are rare, benign lesions that should be considered in the differential diagnosis of cystic lesions identified on imaging especially considering the radiographic presentation which, according to the results of this study, are variable on T1- and T2-weighted MRI. These ectopic RCCs can mimic other aggressive lesions in one of the several ectopic locations in which they have been identified.

LOs: By the conclusion of this session, participants should be able to (1) understand the embryological origins of Rathke's cleft cysts, (2) discuss in small groups the possible origins of ectopic RCCs, and (3) incorporate ectopic RCCs into differential diagnoses of cystic, extra-axial lesions without a clear radiographic diagnosis.