Two cases of mucinous adenocarcinoma of the stomach mistaken as submucosal tumor
A 50-year-old female patient was found to have a gastric tumor during a screening examination performed at another hospital and was referred to our hospital. She had no particular or family history of gastric disease and did not manifest any digestive system related symptom. Endoscopy performed at the other hospital showed an extrinsic mass effect in the lesser curvature of the midbody without mucosal lesion (). Endoscopic biopsy on the area where the mass was observed suggested chronic active gastritis.\nCT showed a well-circumscribed, exophytic, submucosal 5 cm tumor in the lesser curvature of the midbody, partial necrosis inside the mass, and lymph node enlargement around the lesion (). Based on these findings, malignant gastrointestinal stromal tumor was suspected, and laparoscopic partial gastrectomy was planned without a repeat endoscopic examination.\nThe surgical findings revealed numerous lymph node enlargements around the mass and severe adhesion between the posterior wall of the stomach and surrounding tissues. Thus, a frozen section of a lymph node was first examined, and then laparotomy was performed. Frozen section examination suggested metastatic adenocarcinoma, and thus, we decided that surgery for advanced gastric cancer was required. Radical total gastrectomy with D2 lymph node dissection was undertaken and there was a round bulging of the mass in the lesser curvature of midbody and the mucosal surface is slightly red in comparison with the surrounding gastric mucosa but no erosion is evident (), and gross findings showed tumor infiltration of subserosa ().\nThe histopathological diagnosis was mucinous adenocarcinoma and there was no mucosal involvement of the carcinoma microscopically (). The carcinoma was found to have invaded the serosa and metastasized to three of the 34 excised lymph nodes, and thus, the cancer was staged as IIIB (T4aN2M0). The patient was discharged without any particular complication and is currently on outpatient follow-up.