Wrestleview.com’s own Josh Boutwell passed this along:

Perro Aguayo Jr. Hospitalized

AAA star, Perro Aguayo Jr., is currently in Intensive Care at a hospital after having surgery Sunday morning to remove a tumor that was reported to be the “size of a golf ball” from his stomach. Following a Tag Team match last weekend he complained of stomach pains and it got progressively worse as the week went on and was checked into a Hospital on Friday. There have been other outlets that have claimed that he also bursted an ulcer and the tumor may have been cancerous. More news should be on this in the Lucha column. All well wishes go out to Perro Aguayo Jr. and his family!

Source: http://www.revistaluchas2000.com.mx/sac/index.php?option=com_content&view=article&id=1698:perrito-aguayo-ia-cirugia&catid=5:perros-del-mal&Itemid=14