Abstract
Post-transplant lymphoproliferative disorder occurs in approximately one percent of kidney transplant recipients. We evaluated a seventy-seven year-old man with a solid mass in his transplant kidney. On contrast enhanced ultrasound, the mass enhanced but remained persistently hypovascular throughout exam. The enhancement pattern of the mass differed from that typical of clear cell renal cell carcinoma, the main differential diagnosis. Final pathology after partial nephrectomy confirmed post-transplant lymphoproliferative disorder. This is the first report of contrast enhanced ultrasound findings in a renal mass diagnosed as post-transplant lymphoproliferative disorder. Contrast enhanced ultrasound has a promising role in imaging of renal masses, particularly relevant in transplant patients due to the lack of nephrotoxicity.