A Unique Coexistence of Rectal Adenocarcinoma and Gastric Antral Gastrointestinal Stromal Tumor: A Case Report and Minireview.

Several studies have reported the coexistence of gastric gastrointestinal stromal tumors (GISTs) with many primary carcinomas such as gastric and renal cell carcinomas. However, to date reports about the coexistence of gastric GISTs and colorectal adenocarcinoma are limited. Herein we report a unique case of gastric GIST coexisting synchronously with rectal adenocarcinoma in a 36-year-old male patient who presented with weight loss, vomiting, and bleeding per rectum. Computed tomography (CT) revealed circumferential rectal mass coexistent with an irregular gastric soft tissue mass. The diagnosis of rectal adenocarcinoma and gastric GIST was established by immunohistological evaluation of the colonoscopic (rectum) and CT-guided (stomach) biopsies. The patient received concomitant chemoradiotherapy for the rectal adenocarcinoma and neoadjuvant imatinib for the gastric GIST. This was followed by low anterior resection with total mesorectal excision and wedge resection of the gastric mass. Follow-up of the patient for 1.5 years revealed no evidence of disease recurrence. We also present a minireview of the literature that provides insights into this subject as a separate section.