A case of SDH-deficient gastric GIST with pathogenic variant identified in the SDHB gene

Abstract

　Gastrointestinal stromal tumor (GIST) is a rare cancer that can be caused by a germline pathogenic variant in the SDHB gene, which is also causative of hereditary paraganglioma-pheochromocytoma syndrome (HPPS). We report a case of a man in his 30s who was diagnosed with gastric GIST. Immunostaining of the surgical specimen revealed SDHB protein loss, while genetic analysis identified a pathogenic SDHB variant. He started paraganglioma-pheochromocytoma surveillance in addition to standard care for GIST, and we provided follow-up genetic counseling for the psychological burden of having a hereditary disease. In cases of early-onset GIST with SDH-deficient findings, it is useful to consider genetic testing for the possibility of HPPS. Furthermore, evidence is needed regarding the usefulness of surveillance and ongoing psychosocial support for such cases.