The 3 main causes of fat necrosis: Surgery, radiation, and injury. So yes, it can happen. Good that you're getting it checked. It will show up on imaging, it may require a shorter interval follow up, and perhaps even a biopsy to confirm that's what it is.

Fat necrosis is common after ANY trauma to the breast (including post-surgical changes/lumpectomy). It also appears very classic on imaging. Nonetheless, you can evaluate this newly palpable lump with mammography which can easily confirm if what you are feeling is indeed fat necrosis.

Riverajoe, yes, what you are noticing could be fat necrosis.

The good news is that fat necrosis is harmless. The bad news is that on mammogram imaging, while sometimes fat necrosis can be easily identified, other times fat necrosis can mimic the appearance of cancer. So while this hopefully won't be the case, a biopsy may be required depending on how the mass appears on imaging. I am someone who in fact did have to have a core needle biopsy one time for a lump that turned out to be fat necrosis. So that's not to scare you but to warn you... even if a biopsy is needed - and hopefully it's not - this still could be something completely benign and harmless like fat necrosis.

What is Fat Necrosis? https://breast-cancer.ca/necrofat/

"Fat necrosis forms into a lump or pseudo-mass due to fat cells that have either died or been damaged. A mammogram will easily detect this mass.

The only concern is that sometimes the shape and features of a fat necrosis pseudo-mass can be very similar to certain kinds of breast cancer.

Fat necrosis tends to have an irregular or rounded outline. Furthermore, these lumps tend to be smaller in size than other types of masses, usually less than 2cm in diameter."

peggysmom, are you a Breast Radiologist?

I provided a link and quote from a Breast Radiologist. I have personal experience in that I had a mass that had the appearance of cancer but turned out to be fat necrosis. And I've been hanging around here long enough to have seen many others who've had the same experience. Yes, hopefully if Riverajoe's mass is fat necrosis, it will be clear on the imaging. But to say that a mammogram will "easily confirm" if a mass is fat necrosis is setting an expectation that might not be met, as my own experience shows. As I said in another post, we always need to be careful when making definitive statements, because not much about breast imaging and diagnostics is definitive.

peggysmom, Good to know.

We've certainly been missing djmammo these past few months, with a few of us trying to fill the gap. Of course it's a different role when fellow patients are offering advice and our thoughts about someone's situation based on our experiences and learning, vs. someone who is professionally trained. djmammo's presence and knowledge was invaluable, as I'm sure your presence will be, if you continue to post. I always found it interesting that in his responses, djmammo was much less specific and direct than any of the rest of us would be. Over time I've learned from that and try to follow his approach.

peggysmom, question from me as well.

When I had my biopsy for fat necrosis, it was 20+ years after I'd had a couple of excisional biopsies on that breast. The fat necrosis had never shown up on my imaging before, and it was in the same location as those previous surgeries. I always wondered if the surgeries could have been the cause of the fat necrosis, all those years later. Can fat necrosis develop many years after a breast surgery, or was there perhaps some other trauma (that I wasn't even aware of) that caused it?

Hi all. To be perfectly honest, I came to this site seeking solace and wanting to connect with people as a "human" not a breast imager. Maybe it's selfish, but I am here as a patient. Am happy to help out, but really wanted to keep the focus on figuring out how to move forward with my own decisions.

That being said- Fat Necrosis evolves and what it looks like on imaging depends on where it is on the timeline. We see fat necrosis multiple times on a daily basis, it's common! It can be seen from setting ranging from seatbelt injury to post-surgical changes following breast conserving surgery. It doesn't have to be a big trauma, one of the most common scenarios believe it or not is people with large dog/dogs that jumps up on their chest. Most people can't recall an inciting minor trauma!

Fat necrosis can be seen on all modallities, including MRI. Most of the time women don't know they have fat necrosis, it's something imagers see.

Ultrasound is very helpful in the acute setting (in conjunction with mammo) and there are telltale things that support the suspicion of fat necrosis. Fat necrosis from minor trauma typically resovles in a few months. Sometimes, radiologists may assign BiRads-3 for fat necrosis if it's an unusual situation (i.e. Male breast, no definite inciting trauma, etc)- ensure it resolves or "evolves appropriately" over time. By 3 months it should be gone or have evolved into "classic slam-dunk appearing" fat necrosis.

On mammo it is most commonly seen as oil cysts and coarse calcifications. These calcifications 99% of the time LOOK like fat necrosis (maybe not to the untrained eye). The appearance evolves for years due to fibrosis (scarring). After a few years, we dont expect coarse calcifications to further coarsen- there is a plateau afterwhich the fat necrosis changes we see are stable for 10, 15, 20+ years. If there is a change... particularly if the chaging fat necrosis is at site of lumpectomy- it raises suspicion for recurrence and will need to be biopsied. Fat necrosis does not show up far remotely from the time of trauma (i.e. fat necrosis many years after site of excisional biopsy)- however it may take up to 1.5 yrs after trauma until it is FELT by man or woman. (that's how long it takes for that palpable scarred fibrotic calcified lump to form fully). But remember, fat necrosis can be seen on imaging at all stages- it is not necessary to be palpable, radiologists can still see whats happening in the breast even if you cant feel it!

My lumpectomy site was followed for 2-3 years, every six months via mammogram with a description of "likely developing fat necrosis ". Finally it was noted as B-9 and am now on yearly mammogram schedule. Glad they were careful but also glad things have settled!

Riverajoe, thanks for the update, and sorry that you don't have answers and require more testing. Get yourself a copy of today's mammogram and ultrasound report; maybe the written report will provide some insight into what the radiologist thinks this might be.

Good luck with the MRI. Please let us know what happens.

I'll start out saying I have severe anxiety. I have a hard area that formed in breast where surgery and radiation were. I had a lumpectomy end of April. Breast reduction End of May with delayed healing then finished radiation October 20th. My Oncatype was 4 They did mammogram and ultrasound and said most likely fat necrosis but to ease anxiety do a biopsy. Biopsy next week. Am I reading right that they would know 100% of it were fat necrosis from ultrasound? Has anyone ever heard of this ? I have been terrified.

"Am I understanding right that they would have known for sure if it was fat necrosis?"

Unfortunately that answer does not appear to be clear. According to peggysmom, who is a breast radiologist, fat necrosis in most cases "appears very classic on imaging. Nonetheless, you can evaluate this newly palpable lump with mammography which can easily confirm if what you are feeling is indeed fat necrosis." That said, I was sent for a biopsy for what turned out to be fat necrosis, as were many other people who've come through this site, precisely because it was not clear enough on imaging that what we had was fat necrosis.

In your case, if from the appearance on imaging the radiologist believes that what you have is fat necrosis, then it would appear that short-term follow-up imaging would be a reasonable approach instead of having a biopsy now. As peggysmom said, "By 3 months it should be gone or have evolved into "classic slam-dunk appearing" fat necrosis."

What was suggested as follow-up if you opt to not have the biopsy?

Hi Bessie. We didn't discuss other options. He said most patients he would follow up with in 6 months or at annual mammogram. He felt I couldn't handle that. I guess I have to trust what he says. The waiting is a nigh

Great news, Ashlyn! Thanks for letting us know.

Thanks for sharing! So awesome to see you doing well!

Great news Ashlyn!

Amanda, I think that just recently happened to me. I am 2 years out and mine got red, painful and changed. I too have lost weight and think that made a difference. It is getting better but it is a hard lump which I will have to live with. I have not had it looked at yet but common sense said it is not the original cancer because that was slow growing. Thanks for sharing! Congrats on your 10 years~! Happy New Year!