RESPONSE TO QUESTIONS FROM DR. KOPANS. REGARD TO "BREAST TISSUE HYPERPLASIA"

WITH REGARD TO "BREAST TISSUE HYPERPLASIA"

Erplasia” is not valid imaging terminology. “Hyperplasia” is a term that the pathologist uses when looking through a microscope.It basically means that the epithelial cells that usually form a single layer of cells lining the inside of the ducts are forming multiple layers.I am not aware of any valid imaging correlation that can be reliably correlated with this histological finding. 

I suspect that some radiologists are using this term, inappropriately, to describe radiographically dense breast tissue. As you know, the breast contains large amounts of fat (adipose tissue).  There is a wide variation in the normal amounts of connective tissue (regular and specialized) that support the breast and the duct network. The large amounts of regular connective tissue are named after Sir Astley Cooper and called “Cooper’s Ligaments”. 

If we start at the nipple and enter a duct opening, the tube (lined with epithelial cells) will branch back into the breast until we reach the end of the duct and we enter the lobule which is like a hollow bunch of grapes. These cells secrete milk during lactation. The lobules, ducts, and fibrous supporting structures all have the same X-ray attenuation (water density). Consequently, unless you inject a contrast agent into the ducts and fill them back to the lobules, it is rarely possible to differentiate ductal tissue from fibrous connective tissue. All these water containing tissues together are what have been called “dense breast tissue”. 

Since cancers are the same X-ray attenuation as the ducts, lobules (glands), and fibrous tissue, unless they contain calcifications (microcalcifications), or cause architectural distortion, or are set off from the other water density tissues by fat, cancers can be hidden by the dense tissues of the breast.  In the past, radiologists used to describe the dense tissues as “hyperplastic”, but we have dropped this terminology in the U.S. and it is now referred to simply as “dense tissue”.