ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.5 > T21.51 T21.51 Corrosion of first degree of chest wall Non-Billable/Non-Specific Applicable To Corrosion of first degree of breast Codes T21.51XA..., initial encounterT21.51XD..., subsequent encounterT21.51XS..., sequela