Beau Biden, the Delaware Attorney General and son of Vice PresidentJoe Biden, underwent a complicated biopsy of a brain mass at the MDAnderson Cancer Center last night in Houston, NBC News has learned.

"Youcan read from that that it's likely that there was a tumor or some kindof tissue left behind from this mass that was biopsied," NBC News chiefmedical editor Dr. Nancy Snyderman said Wednesday on NBC Nightly Newswith Brian Williams.

Waiting for the results of a biopsy like this may take weeks, Snyderman said.

"These can be very frustrating times for families, because families want answers," she said.

Buttoday, according to a statement from the vice president and Dr. JillBiden, Biden is in "great shape" and will be discharged Thursday.

"Yesterdayour son Beau underwent a successful procedure," the vice president andhis wife said in a statement Wednesday afternoon. "He is in great shapeand is going to be discharged tomorrow and heading home to Delaware. Hewill follow up with his local physicians in the coming weeks."

That Biden is going home is a piece of good news for the family, Snyderman says.

"Itmeans that there were no complications overnight," she said. She saidthere's a possibility that the brain mass may have been the trigger forthe neurological symptoms Biden has experienced, and with its removal,the symptoms could go away, too.