ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.7 > T21.70 T21.70 Corrosion of third degree of trunk, unspecified site Non-Billable/Non-Specific Codes T21.70XA..., initial encounterT21.70XD..., subsequent encounterT21.70XS..., sequela