The Swansea City attacker is racing against time to be fit for the second group game after picking up an injury in the tournament opener and was consequently forced to sit out training on Wednesday and Thursday.
Ghana are already confirmed to be without suspended John Boye and the injured Thomas Agyepong for Saturday's tie.
"Andre Ayew has a small medical problem," Appiah explained in his team update at the pre-match press conference on Friday.
"He trained this morning and he will train this afternoon as well.
"But as to whether he will play or not, I can't give you that information now.
"His availability for the game will depend on today's [second] training.
"Unfortunately John Boye cannot be part of the team but we have other players that can step in."
Andre Ayew and younger brother Jordan, who scored Ghana's second goal against Benin, have been involved in 12 of the Black Stars’ last 16 goals (nine goals and three assists) in Afcon.
Historically, Ghana lost 2-0 to Cameroon in the semi-final of Afcon 2017, and the latter side went on to win the competition.
"The fact that you've beaten a team in the past doesn't guarantee you a win in the next match. It will be a good game. We are ready," Appiah declared.
"We have respect for all teams but this will be a different game. We will give them a very good game."
Ghana currently sit third on the table in Group F, two points adrift of leaders Cameroon.