Is there any condition where a sitting president could extend his term of office beyond the maximum two terms as president?

Yes. If a person becomes president following the death or incapacity of his/her predecessor, and if the person serves less than one half of the predecessor's term, then that person can run for two terms on his/her own. So a person could in theory serve as president for up to 10 years minus one day. If more than half of the predecessor's term is filled by the person, then that person may have only one additional term.