Grade II stakes winner Quintons Gold Rush died Jan. 17 while undergoing surgery at San Luis Rey Equine Hospital in California.Quintons Gold Rush was undergoing a biopsy on a tumor located in his left nasal passage when he died, according to Jay Manoogian, who owned the horse in partnership with Satish Sanan's Padua Stables.The 4-year-old son of Wild Rush was at San Luis Rey undergoing a routine veterinary exam as part of the dissolution of the ownership partnership when the tumor was detected, said Manoogian.Quintons Gold Rush scored the biggest win of his 10-start career in the Coolmore Lexington Stakes (gr. II) at Keeneland. The Coolmore Lexington was his first start for trainer Steve Asmussen since being relocated from the barn of trainer Mike Mitchell. In the Kentucky Derby (gr. I), Quintons Gold Rush finished last in the 18-horse field.Quintons Gold Rush earned $329,835 from a record of 3-1-0.Toyomi Omiya bred Quintons Gold Rush in Kentucky from the Mr. Prospector mare Hollywood Gold.