Former Empress Michiko has a breast cancer and will have an operation, palace officials said Friday.

The Imperial Household Agency said doctors found Michiko had early-stage breast cancer in a regular health check in July.

Michiko, 84, received the title of empress emerita after her husband, Akihito, abdicated on April 30. Their son Naruhito ascended the Chrysanthemum Throne on May 1.

Doctors also found in June that Michiko has a minor heart problem that needs monitoring, though she has continued to make private outings. Michiko also had cataract operations in late June.

Doctors said Michiko has lost weight in recent months, presumably because she was busy preparing for and attending events related to Akihito's abdication, palace officials said. They said she needs to regain her stamina before having an operation, which is expected sometime after September.

Michiko is to travel to Karuizawa in central Japan, where she and Akihito first met at a tennis match, in late August, and to the hot springs resort of Kusatsu as part of their annual vacation plans.

Michiko is the first commoner to become empress in modern Japanese history. Catholic-educated Michiko Shoda and Akihito married on April 10, 1959, after what is known as their tennis court romance.

They broke with traditions and brought many changes to the monarchy. They chose to raise their three children themselves, spoke more often to the public, and made amends for war victims in and outside Japan. Their close interactions have won them deep affection among Japanese.