Journal Article

SDHB/SDHA immunohistochemistry in pheochromocytomas and paragangliomas: a multicenter interobserver variation analysis using virtual microscopy: a Multinational Study of the European Network for the Study of Adrenal Tumors (ENS@T)

Papotti, Mauro, Eisenhofer, Graeme, Mannelli, Massimo, Nesi, Gabriella, de Krijger, Ronald R, Vikkula, Miikka, Pacak, Karel, Korpershoek, Esther, Robledo, Mercedes, Matias-Guiu, Xavier, Gill, Anthony J, Badoual, Cécile, Aydin, Selda, Tissier, Frédérique, Baretton, Gustavo, Oudijk, Lindsey, Favier, Judith, Bialas, Magdalena, Libe, Rosella, Tischler, Arthur S, Lichtenauer, Urs, Rapizzi, Elena, Bertherat, Jérôme, Domingues, Rita, Timmers, Henri J, van Berkel, Anouk, Smid, Marcel, Gimenez-Roqueplo, Anne-Paule, Persu, Alexandre, Volante, Marco, van Nederveen, Francien, Dinjens, Winand NM, Currás-Freixes, Maria, Beuschlein, Felix, Canu, Letizia, Papathomas, Thomas G, Clifton-Bligh, Roderick J, Huynh, Thanh

2015

Overview

Despite the established role of SDHB/SDHA immunohistochemistry as a valuable tool to identify patients at risk for familial succinate dehydrogenase-related pheochromocytoma/paraganglioma syndromes, the reproducibility of the assessment methods has not as yet been determined. The aim of this study was to investigate interobserver variability among seven expert endocrine pathologists using a web-based virtual microscopy approach in a large multicenter pheochromocytoma/paraganglioma cohort ( n =351): (1) 73 SDH mutated, (2) 105 non- SDH mutated, (3) 128 samples without identified SDH-x mutations, and (4) 45 with incomplete SDH molecular genetic analysis. Substantial agreement among all the reviewers was observed either with a two-tiered classification (SDHB κ =0.7338; SDHA κ =0.6707) or a three-tiered classification approach (SDHB κ =0.6543; SDHA κ =0.7516). Consensus was achieved in 315 cases (89.74%) for SDHB immunohistochemistry and in 348 cases (99.15%) for SDHA immunohistochemistry. Among the concordant cases, 62 of 69 (~90%) SDHB-/C-/D-/AF2- mutated cases displayed SDHB immunonegativity and SDHA immunopositivity, 3 of 4 (75%) with SDHA mutations showed loss of SDHA/SDHB protein expression, whereas 98 of 105 (93%) non- SDH -x-mutated counterparts demonstrated retention of SDHA/SDHB protein expression. Two SDHD -mutated extra-adrenal paragangliomas were scored as SDHB immunopositive, whereas 9 of 128 (7%) tumors without identified SDH-x mutations, 6 of 37 (~16%) VHL -mutated, as well as 1 of 21 (~5%) NF1 -mutated tumors were evaluated as SDHB immunonegative. Although 14 out of those 16 SDHB-immunonegative cases were nonmetastatic, an overall significant correlation between SDHB immunonegativity and malignancy was observed ( P =0.00019). We conclude that SDHB/SDHA immunohistochemistry is a reliable tool to identify patients with SDH-x mutations with an additional value in the assessment of genetic variants of unknown significance. If SDH molecular genetic analysis fails to detect a mutation in SDHB-immunonegative tumor, SDHC promoter methylation and/or VHL/NF1 testing with the use of targeted next-generation sequencing is advisable.

• Publisher: Nature Publishing Group US,Elsevier Limited
• Subject: 13/1 / 13/51 / 631/67/1459/1280 / 82 / 82/1 / 82/80 / Adrenal Gland Neoplasms - genetics / Biomarkers, Tumor - analysis / Biomarkers, Tumor - genetics / Electron Transport Complex II - analysis / Electron Transport Complex II - genetics / Humans / Immunohistochemistry - standards / Laboratory Medicine / Medicine / Medicine & Public Health / Microscopy - methods / Mutation / Observer Variation / original-article / Paraganglioma - genetics / Pathology / Pheochromocytoma - genetics / Succinate Dehydrogenase - analysis / Succinate Dehydrogenase - genetics / Telepathology - methods