ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.5 > T21.53 T21.53 Corrosion of first degree of upper back Non-Billable/Non-Specific Applicable To Corrosion of first degree of interscapular region Codes T21.53XA..., initial encounterT21.53XD..., subsequent encounterT21.53XS..., sequela