What happened, in summary

A 74-year-old man was found to have gastric cancer during a routine health check. Endoscopy showed a depressed lesion in the middle part of the stomach, and biopsy identified moderately differentiated tubular adenocarcinoma. A separate nearby submucosal tumor was also seen. CT confirmed situs inversus totalis, meaning the abdominal organs and major vessels were positioned as mirror images of their usual locations. No distant metastases were detected.

Detailed CT angiography was used to map the reversed anatomy and an unusual hepatic artery branch before surgery. He underwent laparoscopic distal gastrectomy with standard lymph-node dissection and Billroth I reconstruction. The surgical team adjusted its usual working positions to account for the mirror-image organ arrangement. The operation lasted 335 minutes with an estimated blood loss of 20 mL.

Pathology showed a 2.1 × 1.3 cm gastric adenocarcinoma that had reached the muscular layer of the stomach wall. There was no lymphovascular invasion or lymph-node spread. The separate 2.2 × 1.8 cm submucosal tumor was a low-risk gastrointestinal stromal tumor. His postoperative recovery was favorable, and he left the hospital 12 days after surgery. At the 1-month follow-up, he was well, had no symptoms, and had no evidence of recurrence.