Breast Fibrosis

Fibrosis refers to a thickening or increase in the density of breast tissue. Fibrous breast tissues include ligaments, supportive tissues (stroma), and scar tissues. Sometimes these fibrous tissues become more prominent that the fatty tissues in an area of the breast, possibly resulting in a firm or rubbery bump.

This page still has some great information. However, check out our new page on breast fibrosis. It has more up-to-date information!

Breast fibrosis is usually caused by menstrual changes, but may also develop following breast surgery or radiation therapy.

Betty Betty
Also, fibrosis naturally develops around breast implants.


Fibrosis of the breast is not associated with breast cancer and does not increase breast cancer risk.

breast fibrosis

Dr. Halls Dr. Halls
The wavy darker purple diagonal on the picture, is actually the fibrosis.

Talking Moose
Talking Moose
That looks like a truck tire track.

Megan Megan
Be nice Moose, or you’ll end up tied to someones roof racks.


Breast fibrosis is a common breast change associated with menstruation

Breast fibrosis is caused by hormonal fluctuations, particularly in levels of estrogen, and can be more acute just before the menstruation cycle begins. Some women experience occasional nipple discharge, usually dark green or brown in color. Fibrosis, along with the development of cysts, are common breast changes that may occur in women through the natural hormonal fluctuations associated with menstruation.

This aspect is basically Fibrocystic disease, and I encourage you to visit that link. But if there is mostly just fibrosis and hardly any cysts, then this page is OK.

Breast stromal fibrosis is common

With stromal fibrosis, the breasts may develop lumps or thickening of breast tissue. Quite often the condition is accompanied by tenderness and pain in the breast. Usually these changes occur in both breasts simultaneously, and the size of the lumps may fluctuate, which are both good clues that there is no concern of breast cancer. (breast tumors tend to occur in one breast only) . Breast fibrosis is also termed more formally as ‘hyaline fibrosis of stroma‘, which simply means a variable increase in dense connective breast tissue. It is a very common finding, occuring in up to 7% of suspicious breast lesions examined by biopsy.

Extremely low risk of breast fibrosis ‘concealing’ an underlying breast cancer

There may be some concern that breast fibrosis might ‘conceal‘ an underlying breast carcinoma, but the evidence is strongly to the contrary. Statistically, un-diagnosed breast cancers occur in less than 3% of breast fibrosis lesions sent for biopsy. As a result, most women with breast fibrosis are recommended for short-term follow up only, unless there are clearly exceptional imaging features which cannot be convincingly distinguished from a malignant tumor. In that case, a second biopsy might be recommended.

Mammographic appearance of breast fibrosis is highly variable

On a mammogram breast fibrosis does not have a specific appearance. The majority of breast fibrosis lesions appear as asymmetric densities. Less commonly they appear as a circumscribed mass or a concealed mass. Breast fibrosis may also appear as a lobulated or microlobulated mass, or just an architectural distortion.

breast fibrosis

Dr. Halls Dr. Halls
This very old ultrasound picture of breast fibrosis, shows the dark area. It blocks ultrasound, so you can’t see below it with ultrasound.

Dr. Halls Dr. Halls
The words “breast fibrosis” in the picture are below the fibrosis, not inside it. The fibrosis was only in the middle of the picture.


With ultrasound, breast fibrosis tends to be variable and somewhat indeterminate, with about 25% showing suspicious features that might prompt a biopsy. About 75% of breast fibrosis lesions are visible to ultrasound, and the majority do appear as a moderately well-defined hypoechoic mass, but they may also appear as either an ill-defined mass or simply as marked shadowing without any visible mass.

Mass-like, nodule-like, and ‘haphazard’ structures

Microscopically, breast fibrosis tends to form into either a ‘mass-like‘ fibrosis, nodular-fibrosis, or simply a ‘haphazard‘ fibrosis. The ‘mass-like‘ cellular configuration tends to feature dense fibrous tissue in which ductal and lobular elements are ‘entrapped‘, dilated, or completely absent. The ‘nodular‘ pattern of breast fibrosis will tend to demonstrate a discrete lobulocentric focus of fibrous tissue, while a ‘haphazard‘ organization would typically show irregular patches of fibrous tissue admixed with fat tissue.

Breast fibrosis does not increase risk for breast cancer

Breast fibrosis does not increase risk for breast cancer in any way, and does not need to be treated. However, it is a good idea to have any breast lumps checked out by your doctor, particularly if it is the first time that breast lumps have been noticed. Some medications can help control symptoms when fibrosis is associated with hormonal changes.

Breast Fibroids

The phrase ‘breast fibroid‘ is not official, not used by doctors when speaking to other doctors. They don’t use it in medical textbooks and you won’t find it published in scientific articles on PubMed. (Go ahead and search on that link, if you don’t believe me).

However, in common use in different parts of the world, it can refer to a benign fibroadenoma, or can be used for anything that feels like a lump that isn’t cancer, for instance a cyst.

The word ‘fibroid‘ by itself, it totally official, and refers to the uterus. Uterus fibroids are leiomyomas. Actually, the breasts can have leiomyomas too, but they are extremely rare.

Fibrosis around breast implants, causes capsular contracture

Any foreign substance implanted in the body, naturally causes the body to lay down some fibrous tissue around it, fibrosis. Over time, particularly around breast implants, the fibrosis gets thicker, and tightens up around the implant. This tightening force is called contracture, and it forces the implant into a more rounder shape, and it feels harder. Another word for this is encapsulation. The encapsulated implant breast augmentation implant, once it occurs, cannot be un-fibrosed.

Radiation fibrosis, radiotherapy treatment effect on the breast

I should make a separate page on this, but because I’m not a radiation oncologist, I’m going to refer you to some other links. I do see often, that post-radiation fibrosis in breasts become harder, and the thickened appearance of the breast is visible on mammograms.

Q and A list:

  • What is stromal breast fibrosis? The word stromal, just means “the whatever-stuff that this part of the body is made of“. So it’s a redundant word. “breast fibrosis” and “stromal breast fibrosis” mean the same thing. Same with “parenchymal“, so parenchymal breast fibrosis, where parenchymal means “whatever-stuff this part of the body is made of“.
  • How to prevent breast fibrosis? I have no idea, about fibrosis prevention, but read-up about fibrocystic disease prevention.
  • Is breastfeeding an issue? Nope. Is “menopause” going to help? Yes. Fibrosis gets thinner as people grow older, and fibrocystic changes certainly recede a lot after menopause.
  • Does radiation to the breast cause fibrosis? YES. thanks for asking. Radiation reaction is a sequence of things that happen, and as it slowly heals itself, from the inflammation, the leaked proteins, the debris of breast cells that died, the body DOES respond to the clean-up and healing by laying down extra fibrosis.


  1. Sklair-Levy M, Samuels TH, Catzavelos C, Hamilton P, Shumak R. Stromal fibrosis of the breast. AJR Am J Roentgenol. (Sept. 2001) 177(3):573-7.
  2. Collette S, Collette L, Budiharto T, Horiot JC, Poortmans PM, Struikmans H, Van den Bogaert W, Fourquet A, Jager JJ, Hoogenraad W, Mueller RP, Kurtz J, Morgan DA, Dubois JB, Salamon E, Mirimanoff R, Bolla M, Van der Hulst M, Wárlám-Rodenhuis CC, Bartelink H; EORTC Radiation Oncology Group. Predictors of the risk of fibrosis at 10 years after breast conserving therapy for early breast cancer: a study based on the EORTC Trial 22881-10882 ‘boost versus no boost’. Eur J Cancer.(Nov. 2008) 44(17):2587-99.
  3. Worsham MJ, Raju U, Lu M, Kapke A, Cheng J, Wolman SR. Multiplicity of benign breast lesions is a risk factor for progression to breast cancer. Clin Cancer Res.(Sept. 2007) 13(18 Pt 1):5474-9.
  4. Revelon G, Sherman ME, Gatewood OM, Brem RF. Focal fibrosis of the breast: imaging characteristics and histopathologic correlation.. Radiology. (July 2000) ;216(1):255-9.
  5. Trujillo, K. A., Heaphy, C. M., Mai, M., Vargas, K. M., Jones, A. C., Vo, P., Butler, K. S., Joste, N. E., Bisoffi, M. and Griffith, J. K. (2011), Markers of fibrosis and epithelial to mesenchymal transition demonstrate field cancerization in histologically normal tissue adjacent to breast tumors. International Journal of Cancer, 129: 1310–1321.
  6. Boyd NF, Lockwood GA, Martin LJ, Knight JA, Byng JW, Yaffe MJ, Tritchler DL. Mammographic densities and breast cancer risk. Breast Dis 1998; 10: 113–26.
  7. Kalluri R, Neilson EG. Epithelial-mesenchymal transition and its implications for fibrosis. J Clin Invest 2003; 112: 1776–84

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