Recently replaced Fiat Chrysler Automobiles CEO Sergio Marchionne suffered an embolism while undergoing an operation for an invasive shoulder sarcoma and has irreversible damage to his brain function, an Italian business website reported Tuesday.

The executive failed to tell FCA Chairman John Elkann of the seriousness of his illness, the report said.

Lettera43, in a report Tuesday citing anonymous sources, said Marchionne, 66, had been diagnosed "long ago" with the invasive shoulder sarcoma — a malignant form of cancer that can develop in the body's soft tissue — and "expressed some doubts" about the effectiveness of the high-risk operation he underwent at the University of Zurich in late June.

Sources told Lettera43, which has led coverage of Marchionne's illness, that during the operation, he was struck by a cerebral embolism, plunging him into a coma. It also claims Marchionne is being kept alive only by machines, and that doctors said there was no hope of recovery.

According to the American Heart Association, an embolism occurs when a blood clot or piece of fatty plaque breaks loose and travels through the bloodstream and becomes lodged in a blood vessel and blocks blood flow. When an embolism blocks the flow of blood to the brain, it is called a cerebral embolism, a type of stroke.

Lettera43 said Marchionne suffered for some time from "severe shoulder pain that made arm movements difficult," according to a translation, and that he took cortisone to soothe it. It said Marchionne also suffered from a chronic thyroid condition for which he had been taking medications for an extended period, which other sources have told Automotive News.

A spokeswoman for FCA US declined to comment on the report.

— You can reach Larry P. Vellequette at [email protected].