"It is a small lesion of about 2 centimeters (less than 1 inch) in diameter, very clearly visible," Chavez told state television.
The announcement throws new uncertainty over the country's politics because the socialist leader is seeking re-election this year, hoping to extend his more than 13 years in power.
Chavez, 57, said the new surgery should be less complicated than what he underwent in Cuba in June, when doctors removed cancerous tumor from his pelvic region. From July to September, he received four rounds of chemotherapy, both in Cuba and in Venezuela, and he has since said that tests show he is cancer-free.
On Tuesday he denied rumors that the cancer had spread to his liver.
In recent weeks, he has recovered the hair that he shaved while undergoing chemotherapy and he has appeared vigorous, returning to his full schedule of activities, including marathon television appearances.