ICD-10-CM > C00-D49 > D00-D09 > D04 > D04.2 D04.2 Carcinoma in situ of skin of ear and external auricular canal Non-Billable/Non-Specific Codes D04.20Carcinoma in situ of skin of unspecified ear and external auricular canalD04.21Carcinoma in situ of skin of right ear and external auricular canalD04.22Carcinoma in situ of skin of left ear and external auricular canal