Small Bowel Lipomatosis: An Unusual Radiological Finding in Patients With Renal Cell Cancer on Pazopanib

Treatment for advanced renal cell carcinoma (aRCC) comprises single agent or combinations of immune checkpoint inhibitors and/or anti-angiogenic agents. Pazopanib is a multitargeted anti-angiogenic tyrosine kinase inhibitor (TKI) approved as treatment for aRCC. We noted that a number of patients receiving pazopanib developed a radiological finding of small bowel lipomatosis. To evaluate the incidence of small bowel lipomatosis in patients with aRCC on treatment with pazopanib in comparison with other tyrosine kinase inhibitors.

We identified 12 out of 208 patients receiving pazopanib to have small bowel lipomatosis and compared their clinic-radiological findings with 314 patients with aRCC receiving other TKIs (sunitinib, cabozantinib, axitinib, and tivozanib). No patients receiving these TKIs developed small bowel lipomatosis.

We compared the radiological findings in patients receiving pazopanib for aRCC. The presence of lipomatosis should not be considered as a clinically relevant finding in these patients. The presence of lipomatosis has no relation with the response to treatment to pazopanib and this is a unique finding seen only in patients on pazopanib.

Small bowel lipomatosis is an occasional finding in patients with advanced renal cancer on pazopanib and is not seen with other TKIs.