Brafv600e and Ctbn1 Mutational Study in Rathke's Cleft Cysts

Antonelli M,Arcella A,Badiali M,Giangaspero F,Minasi S,Buttarelli Fr,Moi L

doi:10.4172/2161-0681.1000291

Abstract

Aim: Rathke's cleft cysts and craniopharyngiomas tipically involve sellar region and their histogenetic relationship is still matter of debate. Clinical and histopathologic differentiation of cystic lesions from the sellar region, that is, craniopharyngiomas (CPs) and Rathke cleft cysts (RCCs), is challenging and has great importance with respect to variable clinical manifestation and adapted surgical treatment strategies in both entities. The recent acquisition that adamantinomatous and papillary craniopharyngiomas bear distinct molecular alterations i.e., β-catenin (CTNNB1) and BRAFv600 mutations respectively, has suggest to screen for such alteration a series of Rathke cyst to seek a possible relation with one of the two craniopharyngioma type. Methods: Seven Rathke's cleft cysts were analyzed for BRAF and CTNNB1 mutational status by sequencing and immunohistochemistry. Radiological, clinical and histological features were performed. Results: None of the 7 Rathke's cleft cysts harbor BRAFV600E mutation. No CTNNB1 mutation was found. Radiological, clinical and histological re-evaluation of the cases confirmed the diagnosis of Rathke's cleft cysts. Conclusion: BRAFV600E and CTNNB1 mutations appeared, as most reliable factor for the differentiation between purely cystic CPs and RCCs, whereas tumor location, tumor size, and radiological parameter of the tumor were less consistent parameters. This study again confirms that craniopharyngiomas (CPs) and Rathke cleft cysts (RCCs), are associated with distinct pathogenic pathways.

Highlights

Rathke’s cleft cyst (RCC) and craniopharyngiomas (CP) involve the cellar region and sometimes histological evaluation is challenging especially when small tissue specimens are available for analysis
Some authors have suggested that these lesions are part of a disease spectrum extending from RCC to craniopharyngioma [2]
Intracystic hemorrhage or inflammation may induce metaplasia in the single cuboidal epithelium of RCC to form stratified squamous epithelia resulting in the induction of craniopharyngioma [3]

Summary

Introduction

Rathke’s cleft cyst (RCC) and craniopharyngiomas (CP) involve the cellar region and sometimes histological evaluation is challenging especially when small tissue specimens are available for analysis. Both lesions are considered to arise from the remnants of Rathke’s diverticulum [1]. Most of the CPs are larger than 20 mm, whereas most of RCCs are smaller than 20 mm in diameter These parameters are insufficient to rule out small cystic CP variants, which do not exhibit any other difference in computed tomography (CT), or magnetic resonance imaging (MRI) [6]

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