This case report is unique in that it highlights how deviations from standard anatomy require careful planning for operative techniques in management and treatment of abdominal masses. Only one case report was located regarding this issue which was regarding an exploratory laparotomy with distal pancreatectomy, partial colectomy, partial gastrectomy, and splenectomy given infiltration of that mass toward the celiac vessels and surrounding organs [5]. Endoscopic ultrasound (EUS) is a commonly used tool in the diagnosis and staging of gastric tumors in order to assess gastric wall involvement and if there is a presence of infiltration in the paragastric lymph nodes [6]. However, there are cases when this is not done or is not possible, and when a patient has a RYGB, the endoscopic route is complicated by the separated remnant stomach such that a mass at the distal end of the remnant would not be accessible on endoscopy. Typically, per the National Comprehensive Cancer Network (NCCN) guidelines for workup of GIST, for a very small gastric GIST (under 2 cm2), EUS in conjunction with CT or MRI of the patient’s abdomen and pelvis can be used, which after that time if the tumor is found to have irregular borders, cystic spaces, ulceration, echogenic foci, and heterogeneity, surgical resection would be warranted [7]. However, per the NCCN, if the mass is known to be suspicious for GIST clinically or there is a known mass based on previous imaging, a chest X-ray imaging becomes warranted, and the surgeon may proceed to resection. Positron emission tomography can be used, but per NCCN does not replace diagnostic CT imaging.

GISTs are abnormal cells of the interstitial cells of Cajal, which are mesenchymal cells known to help move food along in the GI tract [8]. Most commonly found in the stomach, 80% of GISTs have the c-Kit mutation and 10% have the PDGFRA gene, all typically with the CD117 marker. GISTs are often asymptomatic. The decision for adjuvant chemotherapy is based on a number of factors. Of note, patients with c-kit mutations are typically given imatinib as the drug of choice, however, the PDGFRA mutation is resistant to imatinib [9]. Secondly, adjuvant chemotherapy is reserved for those with high-risk features. Per NCCN, risk stratification is based on mitotic rate, location, and size [7]. Gastric tumors smaller than 10 cm, with a mitotic rate under 10 per 50 HPF that have no peritoneal seeding are low risk and do not need adjuvant chemotherapy. Thus, our patient was considered low risk and adjuvant chemotherapy was not indicated.

Our patient followed up with medical oncology in accordance with NCCN guidelines for low-risk disease. This includes follow-up appointments with an oncology with repeat CT imaging of her abdomen and pelvis—MRI is also acceptable—every 3 to 6 months for 5 years then annually if there is no recurrence. If a patient were to be high-risk, 3-month follow-up visits would be indicated [7].