SAO PAULO, April 25 (Reuters) - Brazil's hand-picked presidential successor, Chief of Staff Dilma Rousseff, said on Saturday she is having chemotherapy after lymphoma was found and an isolated tumor was removed.

Rousseff, endorsed by President Luiz Inacio Lula da Silva for the October 2010 election, said she was confident of a full recovery from the cancer, which was found in its early stages.

The tumor, about 2 cm (less than 1 inch) across, was found in her left armpit during routine exams about three weeks ago. The chemotherapy treatment is expected to last for four months.

"The prospects are the best," oncologist Yana Novis told a news conference.

The battle with cancer could cast uncertainty on Rousseff's ability to be a presidential candidate.

By law, Lula cannot seek a third consecutive term. As the global economic crisis pulls at the president's popularity ratings, analysts warn that might impede Lula's ability to push through Rousseff, who trails in early opinion polls.

A tough-talking former left-wing guerrilla, Rousseff has stepped up her campaign in recent months, inaugurating public projects beside Lula and having plastic surgery on her face. (Reporting by Alexandre Caverni and Hugo Bachega; Writing by Inae Riveras; Editing by John O'Callaghan)

AlertNet news is provided by