ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.4 > T25.49 > T25.491 T25.491 Corrosion of unspecified degree of multiple sites of right ankle and foot Non-Billable/Non-Specific Codes T25.491A..., initial encounterT25.491D..., subsequent encounterT25.491S..., sequela