ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.2 > T21.21 T21.21 Burn of second degree of chest wall Non-Billable/Non-Specific Applicable To Burn of second degree of breast Codes T21.21XA..., initial encounterT21.21XD..., subsequent encounterT21.21XS..., sequela