ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.6 > T21.65 T21.65 Corrosion of second degree of buttock Non-Billable/Non-Specific Applicable To Corrosion of second degree of anus Codes T21.65XA..., initial encounterT21.65XD..., subsequent encounterT21.65XS..., sequela