Malignant Gastrocolic Fistula: The Reported Case of Non-Surgical Fistula Closure

Abstract

Purpose: Gastrocolic fistula (GCF) is a pathologic connection between the stomach and colon. GCF as a result of primary gastric lymphoma is extremely rare and usually treated surgically. We present the first case of malignant GCF as a complication of primary gastric lymphoma that resolved with medical therapy alone. A 55-year-old male presented with early satiety, weakness, weight loss, diarrhea, and feculent vomitus for 2 weeks. Past medical history was significant for diabetes, hypothyroidism, and GERD. He had no prior surgical history. He underwent EGD that illustrated a fungating gastric mass with diffusely thickened folds, and feculent matter was seen entering from a fistula at the greater curvature of the stomach. Endoscopic ultrasound was performed and the endoscope entered an opening at the distal greater curvature which led to colonic lumen confirming GCF. Biopsies showed diffuse large B-cell lymphoma. Thereafter, upper GI study and CT scan confirmed GCF. A bone scan was negative for metastasis, and nasojejunal tube was placed endoscopically for enteral nutrition. He was not a surgical candidate due to multiple comorbidities. CHOP therapy was started; however, rituximab was withheld due to risk of bowel perforation. After 3 weeks of tube feedings and medical management of primary gastric lymphoma, a repeat CT scan and EGD showed fistula closure. The gastric mass had decreased considerably in size with significant improvement in gastric wall thickening. Benign etiologies of GCF include peptic ulcer disease, inflammatory bowel disease, pancreatitis, tuberculosis, perforated diverticular disease and infections. GCF can rarely occur as a result of malignancy of the colon or stomach. A malignant GCF forms most commonly between the gastric greater curvature and the distal transverse colon, as was the case with our patient. Barium enema is the most reliable diagnostic test because retrograde contrast administration increases intraluminal pressure, leading to augmented filling of any fistulous tracts. CT with contrast and endoscopic ultrasound scan are used mainly for diagnosing malignant extraluminal disease and staging respectively. Treatment of GCF involves a two-step approach. First is the correction of nutritional, fluid, and electrolyte imbalances; second is the surgical removal of the fistulous tract. Surgery was previously preferred; however, medical management is recommended as the first line therapy in benign disease. Success of medical management for a malignant GCF has not been documented yet. Our case demonstrates that medical management alone may lead to malignant GCF closure in patients with localized primary gastric lymphoma who are poor surgical candidates.