Jorge Mas Canosa spent his final days secluded, with his closest relatives at his bedside, and no one in his inner circle talking to outsiders about his condition.

For months, Mas Canosa and his family tried to keep the seriousness of his illness private, because Mas Canosa did not want to show any sign of weakness to his greatest foe -- Fidel Castro, associates said.

Behind the family's walled compound in the exclusive South Dade neighborhood of Pinecrest, he was unreachable even by longtime friends and associates of the Cuban American National Foundation who rallied around the family to guard their privacy and kept mum about what little they knew of his ill health.

''He didn't want to give the regime of Fidel Castro the pleasure of knowing he was very ill. Even most of us at the foundation knew he was ill -- but we didn't know exactly the magnitude,'' said Eloy Cepero, president of the Latin Builders Association and a foundation director. ''We always clung to the hope that he would recuperate.''

Friends and family respected his wish to the end. Mas Canosa, the foundation's chairman and a founder, died at home Sunday after a battle with lung cancer.

Details of his ill health remain a tightly guarded secret. It was still unclear Monday if Mas Canosa suffered from lung cancer all along or from another type of cancer that spread to the lungs.

''He was conscious until last night,'' his doctor, Alberto Hernandez, said at a press conference Sunday. Hernandez, who takes over Mas' title of chairman of the Cuban American National Foundation, stood by Mas Canosa's casket for most of the all-day and night vigil Monday and did not give further details.

During a recent stay at Pan American Hospital's intensive care unit, Mas Canosa's chart was kept under lock and key. Halls were cleared of all visitors and personnel and sealed off to transport Mas Canosa to radiology, hospital sources said.

His oldest son, Jorge Mas Jr., spoke for the family, mostly through written statements and in short interviews with selected Spanish-language reporters. Mas Jr. insisted that Mas Canosa suffered from Paget's disease and was under such intense treatment that it made him sick. Paget's is a debilitating bone disease but does not usually cause death.

It was widely rumored in the Cuban community, however, that Mas Canosa suffered from life-threatening cancer. The powerful exile leader had been absent for months from major news events in Miami and Washington, as well as from significant private gatherings he customarily attended.

''We knew he was gravely ill, but we never asked questions out of respect for the family,'' anti-Castro activist Silvia Iriondo said at Mas Canosa's viewing Monday. ''We still don't really know the details.''

The last time Cepero saw Mas Canosa was in July, during the foundation's annual congress in Palm Beach. Everyone knew Mas was gravely ill, he said, but they knew few details. Mas Canosa looked ashen and frail. But as usual, he addressed the directors on the topic of Cuba. He said nothing of his health.

''When he finished, he got a standing ovation, and everyone started crying,'' Cepero said. ''We all suspected it would be his last speech.''

The publicly traded company that Mas Canosa led, MasTec, did not disclose Mas Canosa's condition, either.

Publicly owned companies have no obligation to disclose serious illnesses -- or even the death -- of their top executives to investors or the Securities and Exchange Commission. But many companies try to keep investors informed.

Barnett Banks announced Chairman Charles E. Rice's entry into an alcohol rehabilitation program. Coca-Cola openly discussed its late chairman Roberto Goizueta's battle with lung cancer. And W.R. Grace & Co. disclosed Chairman Albert Costello's recent heart attack in a filing with the SEC.

Copyright © 1997 The Miami Herald