ICD-10-CM > S00-T88 > S20-S29 > S20 > S20.1 > S20.12 S20.12 Blister (nonthermal) of breast Non-Billable/Non-Specific Codes S20.121Blister (nonthermal) of breast, right breastS20.121A..., initial encounterS20.121D..., subsequent encounterS20.121S..., sequelaS20.122Blister (nonthermal) of breast, left breastS20.122A..., initial encounterS20.122D..., subsequent encounterS20.122S..., sequelaS20.129Blister (nonthermal) of breast, unspecified breastS20.129A..., initial encounterS20.129D..., subsequent encounterS20.129S..., sequela