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BRAF V 600 E analysis for the differentiation of papillary craniopharyngiomas and R athke's cleft cysts
Author(s) -
Schweizer Leonille,
Capper David,
Hölsken Annett,
Fahlbusch Rudolf,
Flitsch Jörg,
Buchfelder Michael,
HeroldMende Christel,
Deimling Andreas,
Buslei Rolf
Publication year - 2015
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/nan.12201
Subject(s) - immunohistochemistry , pathology , cyst , craniopharyngioma , lesion , biology , differential diagnosis , medicine , endocrinology
Aims The differential diagnosis of cystic epithelial masses of the sellar region, especially the histopathological differentiation of craniopharyngiomas and R athke's cleft cysts, poses a challenge even to experienced diagnosticians. Recently, BRAF V 600 E mutations have been described as a genetic hallmark of papillary craniopharyngiomas. We investigated a series of 33 R athke's cleft cysts to determine the frequency of BRAF V 600 E mutations and its suitability as an additional diagnostic marker for the differentiation of cystic lesions of the sellar region. Methods Thirty‐three R athke's cleft cysts and 18 papillary craniopharyngiomas were analysed for BRAF mutational status by immunohistochemistry using a monoclonal antibody ( VE 1) that selectively recognizes the BRAF V 600 E mutant epitope and additional BRAF pyrosequencing in a subset of samples. Results Thirty of 33 specimens diagnosed as R athke's cleft cysts were negative by VE 1 immunohistochemistry and pyrosequencing, whereas in three cysts and in all the 18 papillary craniopharyngiomas, a BRAF V 600 E mutation was detected. Clinical and histological re‐evaluation of the three BRAF V 600 E mutated cases formerly diagnosed as R athke'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. Conclusions The determination of BRAF mutational status is recommended in any cystic sellar lesion and can in most cases be provided by VE 1 immunohistochemistry even in specimens of low cellularity. Confirmation by (pyro‐)sequencing should be attempted whenever sufficient epithelium is available due to variable staining results.