ICD-10-CM > N00-N99 > N60-N65 > N60 > N60.4 N60.4 Mammary duct ectasia Non-Billable/Non-Specific Codes N60.41Mammary duct ectasia of right breastN60.42Mammary duct ectasia of left breastN60.49Mammary duct ectasia of unspecified breast