Short Review: General Overview of Invasive Lobular Carcinoma (Breast)

This video covers multiple cases of invasive lobular carcinoma, classical type (breast). Routine H&E and selected immunohistochemical stains are reviewed along with grading schemata.
Please let me know in the comments if you have any suggestions for improvements, topics you found confusing, or things that you think may be interesting to have a review on.
Demographics: 00:00
Histology and Differentials:
Cases 1-3 (grade 1): 01:15
Cases 4-6 (grade 2): 10:27
IHC and Specials:
Case 3 (AE1/AE3): 09:50
Case 4 (ER and PR): 12:10
Treatment and Prognosis: 16:17
Clarification: After completing this video, I realized that I did not cover the rest of the genetics often associated with ILC and a few extra differentials.
These are the mutations you can see (these are not required for diagnosis and some are very rare):
- Gains of 1q and 16q (most common)
- Amplification of 1q32, 8p12-p11.2, 11q13
- Gains of 8q
- Losses of 8p23-q21, 11q14.1-q25, 13q
- CDH1 mutations / loss of 16q (E-cadherin is present at 16q22.1)
- HER2 mutations (RARE)
These are some differential diagnoses to consider:
- Mixed carcinoma (contains both ductal and lobular features)
- Tubulolobular carcinoma
- Gastric signet ring cell carcinoma/hereditary diffuse gastric carcinoma syndrome
- Lymphoma
- Metastatic melanoma
- Myofibroblastoma (epithelioid variant)
- Lymphoid aggregate
This video is for educational purposes only and does not represent or replace medical advice. Please consult your physician if you have questions as a patient. If you are a physician, please ensure you research subjects to ensure you have the most up to date information.
All content presented by KL Roncin, MD, unless otherwise noted. Comments and opinions are my own and are current as of the time the video was taken, unless otherwise noted. Please like and subscribe to my channel to receive notifications on any new pathology content!
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@RoncinMD

[@wandalanders8700]

just diagnosed with invasive lobular carcinoma...trying to learn all I can ...Thank you !

[@kroslidereview]

Thank-you so much for your kind words, I hope my brief presentation was of some help towards understanding your recent cancer diagnosis. Please know that we all stand behind you in your battle and wish you only the best. You've got this! #cancersucks #breastcancerawarenessmonth

[@cousiwa09]

Me too, about 2 week's ago. I've also got ca. In my axilla and apical nodes. I wish you well on your journey. Keep in touch with me if you like to. I'm in Australia.

[@wylethathompson1480]

I was just diagnosed on August 23, 2021. We will beat this!!

[@gsflomos]

It's really amazing that these single round lobular cancer cells thrive within the fibrous stroma. It seems that this unique relationship between ILC and fibrous stroma needs further attention in future studies.

[@kroslidereview]

An interesting idea, and one that I have not seen work on myself. I would wonder if it pertains more towards TLDUs naturally occurring within fibrous stroma and subsequent development of ILC secondary to its loss of cell-to-cell adhesion versus some sort of reactive process, given the relative lack of marked inflammation (such as what we often observe with IDC/IC-NST). But we will have to wait and see what the research (eventually!) tells us.

[@gsflomos]

@@kroslidereview Very interesting point. Since TDLUs is the origin of lobular but not only but also for the majority, if not all, of breast cancers. But I wonder if there is more fibroblast ''infiltration'' specifically in lobulars compared to NSTs.

[@kroslidereview]

@@gsflomos There have been several papers on this (nothing really all that recent). Most of them looked into the properties of cancer-associated fibroblasts (CAFs) and the different protein expressions seen in ILC versus IC-NST (ductal). Including a few links below, which hopefully will be helpful. Sadlonova, A., Novak, Z., Johnson, M.R. et al. Breast fibroblasts modulate epithelial cell proliferation in three-dimensional in vitro co-culture. Breast Cancer Res 7, R46 (2004). doi.org/10.1186/bcr949 Westhoff, C.C., Jank, P., Jacke, C.O. et al. Prognostic relevance of the loss of stromal CD34 positive fibroblasts in invasive lobular carcinoma of the breast. Virchows Arch 477, 717-724 (2020). doi.org/10.1007/s00428-020-02835-3 Park, C.K., Jung, W.H. & Koo, J.S. Expression of cancer-associated fibroblast-related proteins differs between invasive lobular carcinoma and invasive ductal carcinoma. Breast Cancer Res Treat 159, 55-69 (2016). doi.org/10.1007/s10549-016-3929-2

[@gsflomos]

@@kroslidereview Thank you for sharing these studies and again thank you for preparing these educational videos that are fantastic!

[@ncorry8491]

Thanks these videos are great, invaluable to trainees. Nice image quality and practical tips 👍

[@kroslidereview]

Thank-you so much for all your fantastic feedback - I really appreciate it and am so glad these videos are helpful!

[@marybryan8088]

I have been diagnosed with this. It is quite a large mass in my breast! What is strange is what looks like a large purplish rash or bruise on the outer skin. No one mentions this.

[@zaferaksit2009]

The targetoid patern is a “intra lobular” one and the single file type is a exrta lobular one. Prognosis is better with the ‘intra’ one. Pleomorphic is G3 and it does invade the lymph vessel and the blood vessels.

[@cousiwa09]

I've just been diagnosed with PILC Stage 3. The slides are interesting,. I'd love to have seen my own.

[@kroslidereview]

Thank-you for your comment and know that we are all behind you as you embark on this journey. While I cannot speak specifically for the pathologist that read your slides, or the institutional policies they work under, some pathologists will go over slides or discuss the case with patients. There are many ways to do this (via digital pathology or even taking some representative photos to email to you), but I believe it never hurts to ask!

[@melodymelody3096]

Thank you👍🏻👍🏻👍🏻👍🏻💕💕

[@kroslidereview]

You are so welcome!

[@user-fc4ui1ou3m]

Thank you for sharing this information. I was recently diagnosed with IDC with lobular features but One never explained this to me. Im ER PR 100 percent positive and Her2 negative. Is my cancer type the same as ILC? My tumor was also big and missed by yearly mammogram starting at the age of 40. I am 55 now.

[@lorij6796]

Hi, 20 yrs ago I had a breast reduction. The pathology report showed signs of Atipical Lobular pre cancer. With a 60% chance of getting cancer. In May 2021 a 3d mammogram and biopsy showed Metastatic ductal carcinoma. The surgeon suggested a lumpectomy. Because of my age and old pathology report I demanded a bi radical mastectomy with nipple removal. Why didn't the recent path report show the Atipical Lobular Carcinoma? Are the both related?

[@kroslidereview]

Great questions. A lot has changed in breast pathology over the last 20 years, in particular with how we respond to certain entities, like the lobular neoplasias (atypical lobular dysplasia (ALD) and lobular carcinoma in situ (LCIS)). While I cannot speak directly as to which of the variants was found in your reduction mammoplasty, how they treat these lesions has changed drastically. For instance, LCIS is no longer staged alongside other cancerous lesions and is not treated aggressively, with exceptions of rare aggressive subtypes. If this was not listed on your most recent report, it is likely that is because it was either not present in the samples they took or it was present but was a type of lobular neoplasia that would not further change your management, since the ductal carcinoma would be the main driver of your treatment options at that point. As far as if they are related, they are more like cousins than siblings with regard to their overall morphology and behavior. The biggest difference is that ductal carcinomas still try to maintain that ductal/donut-shaped structure (which is lost as tumors go up in grade) but lobular carcinomas no longer have the ability to maintain contact with other cells, so they may not present as a mass lesion but rather single cells in the breast tissue.

[@mariapascarella2526]

Is cryoablation a treatment or any other option available instead of surgery to kill the intermediate cells I have stage “0” so the same could also be done for the milk duct carcinoma DCIS and LCIS grade 2. I am trying desperately to avoid surgery. Please send me your best answer for this issue. Thanks!

[@kroslidereview]

Sorry for the wait on my response to you. Overall pathologic staging is based off of the microscopic size of the largest lesion, so a final pathologic staging is not available without surgery. That said, there may be options available based off of features from your biopsy (for example, hormone therapy, radiotherapy, etc). Since I'm not a medical oncologist or radiation oncologist, I really cannot speak to what would be available in your particular case since there are many other considerations they take into account. There may even be clinical trials available that would allow for a non-surgical treatment arm and I'm sure your oncology team will consider all options available.

[@mingfeiyan9927]

nice!

[@kroslidereview]

Thank-you Mingfei!

[@zaferaksit2009]

Have you ever thought about where these cancer cells are driven from? The acini and/or ducts in the picture are normal. The cancer cells come from yhe mesenchime itself. Think about MET (mesenchymal epitelial transition).

[@zaferaksit2009]

This is not ‘medical pathology’, this is just “patern reading”.

[@zaferaksit2009]

Mostly chemotherapy and/or radiotherapy will not work. Think stem cell carcinoma.