ICD-10-CM > S00-T88 > T20-T25 > T24 > T24.4 > T24.43 > T24.439 T24.439 Corrosion of unspecified degree of unspecified lower leg Non-Billable/Non-Specific Codes T24.439A..., initial encounterT24.439D..., subsequent encounterT24.439S..., sequela