SDHB and gastrointestinal stromal tumor: Even though NF1 associated GISTs have been documented to be type 1 SDHB-positive tumors [43], they could be differentiated by several features including the predilection of localization to jejunum/small intestines, common tumor multiplicity, and the lack of GIST-specific mutations (kit and PDGFRa); moreover and alike the SDHB type 2 tumors, they do not respond well to imatinib treatment [43, 45, 46].