Eli Lilly & Co. said John Lechleiter, the drugmaker’s chairman and chief executive officer, will undergo surgery for a dilated aorta, an asymptomatic condition from which he is expected to recover.

Lechleiter, 59, is scheduled to have surgery May 13 to fix the condition that was caught on an unrelated exam, the Indianapolis-based company said Monday in a statement. He is expected to return to work in several months, Lilly said in the statement.

“It is a serious situation but it has been caught early enough,” Edward Sagebiel, a Lilly spokesman, said in a telephone interview. “He is expected to make a full recovery.”

In Lechleiter’s absence, Chief Financial Officer Derica Rice will serve as acting CEO and Ellen R. Marram, Lilly’s lead independent director who has been on the board since 2002, will serve as acting chairman, the company said.

A dilated aorta is a bulge or ballooning of the large artery that carries blood from the heart through the chest and abdomen, according to the National Institutes of Health. The condition can often develop before causing any symptoms.