Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract; most of them have gain-of-function mutations of the KIT gene. There have been rare cases of families with multiple GISTs, that had autosomal dominant germline KIT mutations. Here, we present a case of multiple GISTs caused by a novel germline KIT mutation. Intraoperatively, the main tumor was present in the body of the stomach, and multiple small nodules were detected mainly in the upper and middle part of the gastric wall; several nodules were also present in the small bowel wall. The main tumor and surrounding nodules were resected. DNA sequencing of the tumor tissue, adjacent normal mucosal tissue, and peripheral blood leukocytes revealed that the patient had germline Asp820Gly mutation in exon 17 of the KIT gene. This is the first case with germline Asp820Gly mutation in exon 17 of the KIT gene.
Keywords: Exon 17; GIST; Gastrointestinal stromal tumor.