Omental band induced bowel ischemia following combination immunotherapy in a patient with renal cell cancer.

[PRESENTATION] A 62-year-old female, diagnosed with intermediate IMDC risk metastatic clear cell renal cell cancer, with multifocal metastases to left pleural membrane and primary renal mass in-situ, received combination of 1st line Nivolumab/Ipilimumab therapy. She was admitted to hospital within 2 weeks of administration of 1st cycle of immunotherapy with severe abdominal pain, vomiting, and nausea. On examination, she was noted to have severe abdominal tenderness with positive guarding. Her blood levels showed increased white cell count, C-reactive protein, and high lactate levels.

[DIAGNOSIS] A CT Abdomen and Pelvis and CT Mesenteric Angiogram was performed which showed evidence of mechanical small bowel obstruction. Secondary mesenteric oedema was also noted, and early ischemic changes of bowel were evident.

[TREATMENT] Emergency laparotomy was performed. Omental banding of the small bowel loop was noted. This omental banding had resulted in bowel obstruction and ischemia. She underwent surgical resection of 15cm of gangrenous small bowel with an ileostomy formation. Histological examination revealed inflammatory cells and exudate present in small bowel biopsy sample.

[DISCUSSION] Small bowel obstruction because of an omental band is an extremely rare occurrence. It is thus postulated that the patients omental band developed as a consequence of immune mediated enteritis secondary to immunotherapy. Although small bowel obstruction secondary to immunotherapy is rare, with under five cases in the literature, it is a potentially life-threatening complication that treating physicians need to be aware of.