Surgeons at Israel’s Emek Medical Center in Afula successfully removed a huge Wilms tumor (see here previously) weighing 1.3 kg from a four-year-old child. The tumor, in the right kidney, measured 16 cm by 12 cm and constituted over 7% of the girl’s body weight.
https://tps.co.il/articles/israeli-doctors-remove-1-3-kilo-tumor-from-toddler/
https://www.mayoclinic.org/diseases-conditions/wilms-tumor/symptoms-causes/syc-20352655#