ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.5 > T21.50 T21.50 Corrosion of first degree of trunk, unspecified site Non-Billable/Non-Specific Codes T21.50XA..., initial encounterT21.50XD..., subsequent encounterT21.50XS..., sequela