U.S. first lady Melania Trump has undergone a successful kidney surgery, the White House said in a statement. "That's because she is the first lady", said Dr. Jeffrey Cadeddu, a professor of urology and radiology at the University of Texas Southwestern Medical Center in Dallas.
Trump's communications director, Stephanie Grisham, said the first lady had an embolization procedure, which starves the blood supply to the affected area.
As Pence opened a speech in Washington marking 70 years of Israeli independence, he told the audience that the procedure was not an emergency and that he was pleased to report that it was a "success and Melania is already on the mend".
She had an embolisation procedure on Monday morning at Walter Reed National Military Medical Centre outside Washington, her staff said.
Another time when a president was not at the hospital while the first lady was undergoing surgery was when Laura Bush was having a procedure to help her with pinched nerves in her neck in 2007.
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Last week the first lady announced an anti-cyberbullying initiative called "Be Best", which is aimed at cyberbullying and other issues affecting children.
The White House has not provided any additional details on Mrs Trump's condition.
It is a non-invasive procedure where a catheter is inserted into the primary artery leading to the non-cancerous mass, which then cuts off the blood flow causing the tumor to shrink. It can also be used to block an embolism or an abnormal cluster of blood vessels.
Last week, the first lady, who's 48, unveiled the "Be Best" campaign, which addresses the well-being of children, social media and opioid abuse.
She was last seen in public on Wednesday at a White House event where she and the president honored military mothers and spouses for Mother's Day. She and the president have a son together, Barron, 12.
The first lady lived full time in NY during the administration's opening months so Barron would not have to change schools midyear.