ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.6 > T25.69 > T25.691 T25.691 Corrosion of second degree of right ankle and foot Non-Billable/Non-Specific Codes T25.691A..., initial encounterT25.691D..., subsequent encounterT25.691S..., sequela