Supplementary Material for: Rare Presentation of Spontaneous Transomental Hernia in an Elderly Oncology Patient: Diagnostic Vigilance and Surgical Management

Background Transomental hernia (TOH) is a rare internal hernia, representing approximately 1–4% of all internal hernia cases. The spontaneous form, occurring in patients without a history of abdominal surgery or trauma, is exceptionally uncommon and presents a significant diagnostic challenge due to its nonspecific clinical features. TOH typically involves herniation of small bowel loops through a defect in the greater omentum. Case Presentation We report a case of spontaneous TOH in a 76-year-old male undergoing chemotherapy for synchronous primary malignancies—left lung adenocarcinoma and right renal cell carcinoma—who presented with features of intestinal obstruction. Contrast-enhanced computed tomography (CECT) suggested internal herniation with ischaemia. Intraoperative findings confirmed approximately 100 cm of small bowel incarcerated through a 3 cm defect in the right side of the greater omentum. Age-related omental atrophy, along with chemotherapy-induced mesenteric fibrosis, microvascular injury, and impaired regenerative capacity, likely contributed to the defect formation. An emergency midline laparotomy was performed, involving resection of the gangrenous bowel and the creation of a double-barrel enterostomy. Postoperatively, distal enteral refeeding was critical in electrolyte correction, nutritional support, and early recovery. Discussion TOH carries a high risk of strangulation and should be considered in elderly patients with bowel obstruction, even with no history of prior abdominal surgery, especially those receiving platinum-based chemotherapy. Conclusion Although rare, TOH should be included in the differential diagnosis of acute abdomen in elderly oncology patients, even without previous abdominal surgery. Timely surgical intervention is vital to reduce morbidity and optimize outcomes.