Tumour-bowel fistula as a possible complication of pazopanib therapy in retroperitoneal leiomyosarcoma.

Pazopanib is a vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGFR TKI) that inhibits the vascular endothelial growth factor receptor A pathway and has the potential to cause ischaemic bowel changes, including perforation. Here we report a case of a 51-year-old man with large, metastatic, retroperitoneal leiomyosarcoma that developed a tumour-bowel fistula after 4 weeks of pazopanib therapy. He presented to the emergency department with sepsis and 1-week history of worsening fever, chills, nausea and diarrhoea. Abdominal CT findings of mesenteric and portal vein gas, commonly found in mesenteric ischaemia and VEGFR modulator-induced bowel toxicity, provided evidence for the causal relation. Unfortunately, the case was not amenable to surgery and patient succumbed to the illness.