Lobular carcinoma in situ: Clinical sciences

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Introduction0:00–0:48

Lobular carcinoma in situ, or LCIS, refers to the non-invasive proliferation of epithelial cells in the terminal ductal lobular unit of the breast.
LCIS typically presents as an incidental finding on a breast biopsy done for a separate reason. Further management depends on its histologic type, which includes classic LCIS or other more aggressive variants.
Classic LCIS is not considered a malignant finding requiring treatment, but rather a risk indicator for the later development of invasive carcinoma in either breast.
On the other hand, more aggressive variants include pleomorphic or florid LCIS, which are more likely to progress into invasive lobular carcinoma.When assessing a patient that presents with LCIS, first obtain a focused history and physical exam.

Initial assessment0:48–1:30

Patients often discover LCIS from getting a core needle biopsy after an abnormal screening mammogram for a different concern.
Your next step is to ask about risk factors, such as age over 40, a personal or family history of breast cancer or genetic mutations, and any usage of hormone replacement therapy, especially for more than five years.
On physical exam, LCIS does not usually have any significant findings, but in rare cases, you might be able to palpate a breast lump.
Ok, now that we’ve performed our history and physical exam, let’s take a closer look at the results of the biopsy specimen that showed LCIS in the first place.

Pathology assessment of LCIS histology1:30–2:01

It’s important to know that LCIS can be broadly classified as classic LCIS and more aggressive variants. While they have a few things in common, they vary by the amount of cellular atypia and proliferation, and therefore the degree of risk for malignancy they carry.
So, as you can imagine, each type has a different management. Alright, let’s start with classic LCIS.

Classic LCIS2:01–3:52

So, core needle biopsy might show small, round, uniform, discohesive cells that fill and expand greater than half of the acini of the breast lobule.
Although the acini are distended, the overall architecture of the lobule and its basement membrane remains intact. If you see these findings, you have a diagnosis of classic LCIS.
In terms of management, the treatment of classic LCIS is going to largely focus on close surveillance and risk reduction.
Follow up in six to twelve months with a clinical exam, and make sure to get yearly screening mammograms. Also, consider adding a breast MRI to the yearly screening.
Risk reduction starts with counseling on modifiable lifestyle factors, such as exercise, maintaining a normal BMI, and limiting alcohol use.
You’ll also want to talk to your patient about starting chemoprevention, such as a selective estrogen receptor modulator or SERM like Tamoxifen, which can significantly reduce the risk of future breast cancers in both breasts.
In the past, many patients actually underwent prophylactic bilateral mastectomy for LCIS, but for most patients, it turns out this is not necessary.
However, some patients, either according to their individual values and wishes or because they fall under a high-risk group, may still want to consider this option.
High-risk patients include those with known BRCA mutations, significant family histories of breast or ovarian cancer, or prior thoracic radiation at an age of less than thirty.
If this is the case, refer them to a breast surgeon for further discussion. Ok, now that we’ve talked about classic LCIS, let’s go back to the core needle biopsy results to consider more aggressive variants.

More aggressive variants of LCIS3:52–4:54

Let’s say your biopsy shows large, discohesive cells with pleomorphic nuclei, that markedly distend the acini of the breast lobules, and may even have some central necrosis.
This is suspicious for a more aggressive variant of LCIS, which is basically LCIS with increased cellular atypia and proliferation.
Or, let’s say you have a core needle biopsy result that looks like classic LCIS on histology, but some finding on the diagnostic imaging makes you suspicious that the tissue sample may not fully explain the imaging findings, such as a solid nodule.
When this happens it is called radiologic-pathologic discordance. If either of these situations occurs, suspect a more aggressive variant of LCIS.
The next step would be to get a surgical biopsy to examine more tissue and confirm the diagnosis. Alright, now that the biopsy has been performed, re-evaluate the histology findings.

Biopsy4:54–6:28

If the biopsy only showed the same small, uniform, discohesive cells filling the lobule acini, you can confirm classic LCIS.
In this case, management is the same as mentioned earlier, meaning surveillance, risk reduction with lifestyle modifications and chemoprevention, and individualized considerations for a prophylactic bilateral mastectomy.On the other hand, if the biopsy still shows large, discohesive cells, go ahead and confirm the diagnosis of a more aggressive variant of LCIS.
Then, make sure to assess the margins of the resection specimen. If they are clear and do not have any evidence of LCIS, there is no need for further resection.
As before, long-term management will consist of surveillance, risk reduction with lifestyle modifications and chemoprevention, and individualized considerations for a prophylactic bilateral mastectomy.
Okay, let’s take a step back. If margins are not clear of pleomorphic LCIS, the patient will need re-excision to ensure clear margins.
Once this is done, and it is again confirmed that the resection margins are clear, go ahead and proceed with the same long-term management as before, including surveillance, risk reduction with lifestyle modifications and chemoprevention, and individualized considerations for a prophylactic bilateral mastectomy.Okay, let’s go back to biopsy and talk about other possible findings.

Concurrent DCIS6:28–7:25

Sometimes, a biopsy might reveal additional findings that might diagnose a concurrent malignancy. For example, if your biopsy has evidence of classic or a more aggressive variant of LCIS, but may also show findings like neoplastic ductal epithelial cells confined by basement membrane, consistent with concurrent ductal carcinoma in situ, or DCIS.
Unlike LCIS, which is considered a risk for cancer, DCIS actually is cancer. You will treat the patient according to the more dangerous lesion, which in this case is DCIS.
This includes establishing the estrogen receptor status, surgical consultation for a partial or total mastectomy, and, depending on circumstances, adjuvant therapies such as radiation and hormone therapy.
Now that we’ve talked about finding DCIS, let’s consider the possibility of finding an invasive lobular carcinoma. Your biopsy might show classic or more aggressive variants of LCIS, with evidence of invasive cancer.

Invasive lobular carcinoma7:25–7:53

If this happens, you can diagnose an invasive ductal or lobular carcinoma. Your next step here is to perform TNM staging, and treat accordingly.Alright, as a quick recap… LCIS usually presents as an incidental finding after a core needle biopsy performed for another indication.

Review7:53–8:49

Start by determining if the histology is classic or a more aggressive variant. In classic LCIS, management consists of surveillance, risk reduction, chemoprevention, and for select patients prophylactic bilateral mastectomy.
If a more aggressive variant of LCIS is suspected, get a biopsy to confirm the diagnosis. If the biopsy shows a classic LCIS, manage it as described.
Now, if the biopsy confirms a more aggressive variant of LCIS, check the margins of the specimen to make sure they’re clear.
If the margins are not clear, re-excision is necessary. Once margins are clear, manage it the same as before.
Finally, if concurrent DCIS or an invasive lobular or ductal carcinoma are found on biopsy, the patient has breast cancer and should be treated accordingly.
on biopsy the
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