SDHB and gastrointestinal stromal tumor: SDHB and SDHA mutated GIST consist of a subgroup of young adult women patients with a well distinct clinical and biological profile, usually characterized by the gastric primary tumor localization, a principally mixed epithelioid and spindle cell morphology, diffused IHC positivity for KIT and revealed on gastrointestinal stromal tumors 1 (DOG1), recurrent lymph node metastases, and an nonaggressive course of disease even if metastasis is identified.