BRAF V600E analysis for the differentiation of papillary craniopharyngiomas and Rathke's cleft cysts. (2nd May 2015)

• Record Type: Journal Article
• Authors: Schweizer, Leonille; Capper, David; Hölsken, Annett; Fahlbusch, Rudolf; Flitsch, Jörg; Buchfelder, Michael; Herold‐Mende, Christel; von Deimling, Andreas; Buslei, Rolf
• Is Part Of: Neuropathology & applied neurobiology. Volume 41:Number 6(2015)
• Page Start: 733
• Page End: 742
• Publication Date: 2015-05-02
• Subjects: Nervous system -- Diseases -- Pathology -- Periodicals; Nervous system -- Diseases -- Periodicals; 616.8
• DOI: 10.1111/nan.12201
• Languages: English
• ISSNs: 0305-1846

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="nan12201-sec-0001" sec-type="section"> <title>Aims</title> <p>The differential diagnosis of cystic epithelial masses of the sellar region, especially the histopathological differentiation of craniopharyngiomas and Rathke's cleft cysts, poses a challenge even to experienced diagnosticians. Recently, <italic>BRAF V</italic><italic>600</italic><italic>E</italic> mutations have been described as a genetic hallmark of papillary craniopharyngiomas. We investigated a series of 33 Rathke's cleft cysts to determine the frequency of <italic>BRAF V</italic><italic>600</italic><italic>E</italic> mutations and its suitability as an additional diagnostic marker for the differentiation of cystic lesions of the sellar region.</p> </sec> <sec id="nan12201-sec-0002" sec-type="section"> <title>Methods</title> <p>Thirty‐three Rathke's cleft cysts and 18 papillary craniopharyngiomas were analysed for <italic>BRAF</italic> mutational status by immunohistochemistry using a monoclonal antibody (VE1) that selectively recognizes the BRAF V600E mutant epitope and additional <italic>BRAF</italic> pyrosequencing in a subset of samples.</p> </sec> <sec id="nan12201-sec-0003" sec-type="section"> <title>Results</title> <p>Thirty of 33 specimens diagnosed as Rathke's cleft cysts were negative by VE1 immunohistochemistry and pyrosequencing, whereas in three cysts and in all the 18 papillary craniopharyngiomas, a <italic>BRAF V</italic><italic>600</italic><italic>E</italic> mutation was detected. Clinical and histological re‐evaluation of the three <italic>BRAF V</italic><italic>600</italic><italic>E</italic> mutated cases formerly diagnosed as Rathke's cleft cysts revealed unusual presentations. Two of them were rediagnosed as papillary craniopharyngiomas. The patient of the third case had a history of craniopharyngioma operated 14 years before, and reoperation showed a cystic epithelial lesion with unclear histology.</p> </sec> <sec id="nan12201-sec-0004" sec-type="section"> <title>Conclusions</title> <p>The determination of <italic>BRAF</italic> mutational status is recommended in any cystic sellar lesion and can in most cases be provided by VE1 immunohistochemistry even in specimens of low cellularity. Confirmation by (pyro‐)sequencing should be attempted whenever sufficient epithelium is available due to variable staining results.</p> </sec> </abstract>