ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.4 > T25.41 > T25.412 T25.412 Corrosion of unspecified degree of left ankle Non-Billable/Non-Specific Codes T25.412A..., initial encounterT25.412D..., subsequent encounterT25.412S..., sequela