While multiple terms for the underlying conditions associated with SDH‐deficient GIST exist, we will define and standardly use GIST lacking SDHB IHC expression as SDH‐deficient GIST, germline mutations in the SDHx genes as a subset of the broader condition Hereditary Paraganglioma‐Pheochromocytoma (HPGL) [16, 17], and epigenetic methylation of the SDHC promoter region as epimutant [18]. The gene discussed is SDHC; the disease is gastrointestinal stromal tumor.