Mubarak was on Saturday questioned over a long list of gifts worth $1 million that he and his family members and ministers received from a newspaper while in power, an official said.
Mubarak was moved to the hospital yesterday as there was no CT scanning device in Tora jail where 84-year-old Mubarak is serving a life-sentence term.
Ali Abdullah Saleh is receiving treatment at the defence ministry hospital.
The blast took place in a tent used as a dining room by students at the city centre hospital.
The area that was hit was used to train doctors, a report said.
Egypt`s ex-president and his sons were remanded into custody this week.
Day in Pics: 1st October
Showbiz World - October 1, 2014
George Clooney - Amal Alamuddin grand Venice wedding