ICD-10-CM > S00-T88 > T20-T25 > T24 > T24.6 > T24.63 > T24.639 T24.639 Corrosion of second degree of unspecified lower leg Non-Billable/Non-Specific Codes T24.639A..., initial encounterT24.639D..., subsequent encounterT24.639S..., sequela