In the Egyptian-Ottoman wars (1800s), Egypt was originally a vassal of the Ottoman Empire, but had been ruled essentially autonomously from the rest of the empire. Muhammed Ali, the ruler of Egypt, wanted to cement his power in Egypt, and demanded control of Syria. After a brief conflict, Muhammed Ali's troops took over Syria for a bit. However, the Ottomans wanted revenge, and after foreign powers intervened, Muhammed Ali renounced his claims on Syria and other lands, but received basically permanent control of Egypt for him and his heirs. In hindsight, he really made off like a bandit.

Interesting question.

Russia lost significant territory after World War 1. Hard to tell if this counts since they dropped out of the war before the entente defeated Germany, but you could argue that they were part of the winning side.