Fibrocystic change of the breast

by Vanessa Grace M. De Villa-Atienza, MD, DPSP
November 6, 2022

What does fibrocystic change mean?

Fibrocystic change (FCC) is a term used to describe a group of non-cancerous changes that often develop together in the breast. These changes include cysts, fibrosis, apocrine metaplasia, and adenosis. It is a common finding seen in up to 60% of reproductive-aged women. Another name for FCC is fibrocystic disease.

What causes fibrocystic change?

FCC is believed to develop in response to stimulation from hormones such as estrogen and progesterone.

How do pathologists make the diagnosis of fibrocystic change?

The diagnosis of FCC can be made after a small sample of tissue is removed from the breast in a procedure called a core needle biopsy. The biopsy may be performed after densities or calcifications were seen on mammography. FCC can also be seen in tissue removed to diagnose or treat cancer or other non-cancerous condition in the same breast.

What does fibrocystic change look like under a microscope?

Cysts

Normal glands in the breast are small, round structures that often look empty when examined under the microscope. A cyst is an enlarged, fluid-filled gland. These cysts can be single or numerous and may be varied in size. When groups of cysts or single cysts become large enough, they can be felt when the breast is examined. Over time, some of the calcium in the fluid is left in the tissue where it creates calcifications. These large cysts and calcifications can be seen as abnormalities on ultrasound or mammography.

Stromal fibrosis

If a cyst breaks, the fluid inside will spill into the surrounding stroma. This can cause inflammation and the creation of new stromal fibroblasts. Over time this reaction can create a scar that pathologists describe as fibrosis.

Apocrine metaplasia

Metaplasia is a word that pathologists use to describe a change from the normal cell type to another cell type. It is a non-cancerous type of change. In apocrine metaplasia, the epithelial cells lining the breast ducts change from columnar cells to apocrine cells. Apocrine cells are easy to see under the microscope because they are larger than normal cells and the body of the cell (the cytoplasm) is bright pink.

Adenosis

Adenosis means an increased number of glands in the breast. It is also a non-cancerous change. The new glands may be larger than the normal glands and some may contain fluid. Adenosis is often seen together with columnar cell change and columnar cell hyperplasia.

Is fibrocystic change associated with an increased risk for breast cancer?

Fibrocystic changes are not associated with an increased risk of developing breast cancer.