This case-insensitive code system http://hl7.org/fhir/us/breast-radiology/CodeSystem/DuctAbnormalityTypeCS defines the following codes:

Code	Display	Definition
DuctNormal	Duct normal	Duct is considered normal. It is surrounded by normal cells and collagen in the breast with no abnormalities. A system of ducts in the breast carries milk to the nipples.
SolitaryDilatedDuct	Solitary dilated duct	When it is malignant, solitary dilated duct appears to indicate the presence of DCIS. In almost all solitary dilated duct cases, the dilated duct appears to be filled with some debris, with or without accompanying fluid, as seen at ultrasound.
DuctEctasia	Duct ectasia	A noncancerous condition that results in clogged ducts around the nipple. While it sometimes causes pain, irritation and discharge, it's generally not a cause for concern. If left untreated, it can eventually obliterate the breast duct. www.healthline.com > health > duct-ectasia-of-the-breast