Please help. Excision of ear cyst on tympanic membrane

Hi, I need to know the best code for a cyst removal on tympanic membrane for a child. I looked at 21011 and 69145. Is there a better code? I am stuck.. And I don't have more information than the "child is going to have removal of cystic mass which overlies the tempanic membrane.. Any suggestions would really help a girl out.. Thanks all!!!