Introduction: Iatrogenic diaphragmatic hernias have been reported as a rare complication of abdominal surgery, and only a few reports have suggested minimal intraoperative injury to the diaphragm as a cause. Presentation of case: We report a rare case of delayed diaphragmatic hernia caused by laparoscopic excisional biopsy of a peritoneal lesion on the diaphragmatic peritoneum. A 70-year-old woman with gastric gastrointestinal stromal tumor underwent laparoscopic partial gastrectomy and excisional biopsy for white nodules on the left diaphragmatic peritoneum using laparoscopic scissors. Slight bleeding that occurred after excisional biopsy was stopped using a soft-coagulation system. Six months after her first surgery, a left diaphragmatic defect and transverse colon migration into the thoracic cavity were detected on computed tomography. The patient subsequently underwent laparoscopic diaphragmatic hernia repair. The site at which the diaphragm defect occurred was consistent with the site of excisional biopsy. The defect was closed with interrupted suturing using non-absorbable threads, following which a composite mesh was applied above the suture site for reinforcement. Discussion: This is the first report of an iatrogenic diaphragmatic hernia after diagnostic laparoscopy for peritoneal excision biopsy of the diaphragmatic surface. In the present case, the coagulation procedure for hemostasis after peritoneal resection was considered to be the cause of the diaphragmatic hernia. The heat generated by soft coagulation might have unexpectedly reached and damaged the deep areas of the diaphragmatic muscle. Conclusion: Surgeons performing laparoscopic excisional biopsy of the diaphragmatic peritoneum should consider the potential risk for iatrogenic diaphragmatic hernias. Highlights:

Intestinal malrotation, which arises from incomplete rotation of the embryonic midgut, is one of the congenital anomalies usually diagnosed in infancy. On the other hand, intestinal malrotation detected in asymptomatic adults is very rare. It is frequently diagnosed incidentally during abdominal surgery. We report a case of asymptomatic intestinal malrotation diagnosed during laparoscopic distal gastrectomy for gastric cancer. A 59-year-old female was diagnosed with early-stage gastric cancer during health screening and admitted to our hospital for radical surgical treatment. Physical examinations and blood tests revealed nothing of note. The type 0-IIc gastric cancer was located in the posterior wall of the mid-body of the stomach. The histological type was poorly differentiated adenocarcinoma. Esophagogastroduodenoscopy and computed tomography (CT) suggested that the depth of tumor invasion was the submucosal layer without regional lymph node swelling. The clinical stage according to the TNM 7th edition was cT1b N0 M0, cStage I. Laparoscopic distal gastrectomy with D1+ lymph node dissection and Billroth-I method reconstruction was planned. During the infrapyloric lymph node dissection, a part of the pancreatic head showed unusual adherence to the first part of the duodenal wall. For safe and accurate lymphadenectomy while avoiding pancreatic injury, we deliberately focused on tracing the dissectible layer between the pancreatic parenchyma and fatty tissues including lymph nodes. Also, we changed the reconstruction procedure from Billroth-I to Roux-en-Y. After distal gastrostomy, we could not find the ligament of Treitz or jejunum on the left side below the transverse colon. Based on a review of the CT image, this patient was diagnosed with intestinal malrotation. Although the detection of malrotation during the operation was incidental, we could complete radical surgery and Roux-en-Y reconstruction safely. The type of malrotation was non-rotation (90°). She was discharged from our hospital without any complications. We encountered a case of adult asymptomatic intestinal malrotation with gastric cancer. Even when encountering such a case during laparoscopic gastrectomy, reviewing CT images carefully to reconsider the anatomical anomalies, and tracing the dissectible layer accurately with adequate countertraction can facilitate safe and successful surgery.