Gastrointestinal stromal tumors of the duodenum: a report of four cases

Here, we report four cases of duodenal gastrointestinal stromal tumors (GISTs). In three patients, endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS FNAB) was performed, and in one patient, the tumor tissue was sampled via forceps biopsy. In all the cases, GISTs could be diagnosed by histopathological examination of the biopsy samples. Ki-67 labeling indexes (Ki-67 LIs) of the 3 EUS FNAB samples were very low. It should be noted that a sufficient amount of tissue sample could not be obtained in one of these cases. In two patients who underwent laparotomy, the Ki-67 LIs of the biopsy samples corresponded with the Ki-67 LIs of the surgically resected samples and were also consistent with the tumor risk grade. In two patients who did not undergo laparotomy, the low Ki-67 LIs corresponded with a good clinical course.