A 55-year-old gentleman, ex-smoker, presented to our hospital complaining of mild epigastric pain, regurgitation, and heartburn. On top of that, he has a long-standing history of gastroesophageal reflux disease (GERD), which was managed by proton pump inhibitors. His past medical history was significant for hypertension. He was previously diagnosed with a liver hemangioma based on abdominal ultrasound two years before the presentation. He had no relevant family history. Physical examination revealed mild epigastric tenderness with no palpable abdominal mass. Laboratory data showed no anemia but positive stool occult blood test. Tumor markers including AFP, CEA, and CA 19-9 were all within normal range. Upper GI endoscopy revealed mild esophagitis, Los Angles grade A along with Barrett's esophagus without dysplasia and a 1 cm polyp at the GEJ. A sample was sent for histopathology; the rest of the stomach and duodenum were normal. The patient did not have a previous endoscopy prior to this one.
Infused computed tomography (CT) of the abdomen and chest showed mild GEJ thickness with no evidence of mediastinal or celiac lymphadenopathy and no signs of metastasis. It also demonstrated a large heterogeneously enhancing mass about 6 x 9.5 cm with central necrosis in the upper abdomen that appears to be originating from the gastric antrum (greater curve). The mass was highly suggestive of GIST based on CT; it was the same mass that was previously misdiagnosed as a liver hemangioma (Figure 1). Endoscopic ultrasound confirmed the previous findings. However, no biopsy was attempted due to the risk of bleeding.
Histopathological examination of the GEJ polyp revealed tubulovillous adenoma with elements of adenocarcinoma in situ. The patient was admitted with a provisional diagnosis of early-stage adenocarcinoma of GEJ along with the incidental finding of enlarging gastric GIST. A trial of endoscopic mucosal resection of GEJ polyp was attempted but failed because of the polyp location that created a technical difficulty. Therefore, the patient was taken to the operating room with a plan to perform a wedge resection of the gastric mass and a submucosal resection of GEJ polyp through the same gastric opening. We planned to use frozen section (FS) to document negative margin resection and determine the need for a formal esophagectomy. Intraoperatively; a large (10 x 7 x 6 cm), extraluminal pedunculated mass was found at the posterior wall of the greater curvature of the stomach (Figure 2). Wedge resection of the gastric mass with negative margins was achieved along with a transgastric submucosal resection of the GEJ polyp. Fortunately, the FS examination of the polyp showed negative margins as well with no evidence of deep invasion. Postoperatively, the patient had a smooth course and was discharged home in a stable condition. The final pathological examination revealed a GEJ polyp around 1.7 x 1.4 x 0.6 cm. Microscopically, there was a focus of invasive adenocarcinoma involving the superficial submucosa of the polypoid lesion, negative margins, and no lymphovascular invasion (T1a NxM0). Furthermore, the gastric wall mass measured around 10 x 7 x 6 cm with a 2 x 1.5 cm stalk. Histopathology revealed encapsulated high-grade epithelioid GIST tumor with negative margins (pT3). The mitotic rate of 6/50 HPF and immunohistochemical stains were positive for DOG1 and CD34 but negative for CD117 (c-Kit) (Figure 3).
The final diagnosis was synchronous early-stage GEJ adenocarcinoma and a high-grade gastric GIST. Therefore, the patient was started on adjuvant imatinib treatment, along with endoscopic surveillance every six months and proton pump inhibitors.