Large studies analyzing the SDH status using immunohistochemistry for the SDHB subunit supported the notion that SDH deficiency is in general mutually exclusive to other known oncogenic mechanisms.7, 8, 9 The most extensive series investigated 756 gastric GIST by SDHB immunohistochemistry and identified 66 SDHB deficient GIST, whereas all 378 non‐gastric GISTs were found to be SDHB‐competent.6 Heterogeneity of the staining pattern for SDHB was not reported, and staining was performed on a tissue microarray where individual cores might not represent the full morphologic spectrum of the tumors. Here, SDHB is linked to gastrointestinal stromal tumor.