Dilated Duct Pattern at Mammography

The appearance of symmetric bilateral subareolar ductal dilatation is usually of no clinical importance in postmenopausal women. Asymmetric dilatation is another story. Asymmetrically dilated ducts can be caused by:

• Primary: Intraductal growth of papilloma or intraductal carcinoma
• Secondary: Duct retraction by architectural distortion from adjacent mass, or ductal obstruction from mass.

The following should raise concern for malignancy in an asymmetrically dilated duct:

• Nonsubareolar location
• Interval change
• Suspicious microcalcifications

References

Huynh PT, Parellada JA, de Paredes ES, Harvey J, Smith D, Holley L, Maxin M. Dilated duct pattern at mammography. Radiology. 1997 Jul;204(1):137-41.