Pakistan Army has followed British Army rank system since its independence from British Empire in 1947. However, the crown in the ranks has been replaced with a star and crescent, which symbolizes the sovereignty of Government of Pakistan.
A Lieutenant general or leftenant-general in the Pakistan Army is equivalent to a vice admiral in the Pakistan Navy and an air marshal in the Pakistan Air Force. A lieutenant general is also called a three-star general. Like other armies, this rank is higher than a major general and lower than a full general.
References
Lieutenant general (Pakistan) Wikipedia(Text) CC BY-SA