TOKYO, June 16 (Reuters) - Japanese share prices tumbled on Thursday, with the broad Topix index falling to a four-month low, after the Bank of Japan refrained from introducing more stimulus.

Although such an outcome had been widely expected, there had been some speculation about easing due to the fragile state of the Japanese economy and BOJ Governor Haruhiko Kuroda's history of surprising markets with policy decisions.

The Topix fell as much as 2.2 percent to 1,249.04, its lowest level since mid-February while the Nikkei average fell up to 2.2 percent to 15,576.60, its lowest level since mid-April.

Carmakers were among the worst hit, as the BOJ's decision pushed the yen more than one percent higher to a near 22-month high of 104.505 yen per dollar. Nissan Motor fell 2.0 percent while Toyota Motor shed 2.3 percent.

(Reporting by Hideyuki Sano; Editing by Sam Holmes)