Transcription
What's up guys? How are you doing today? I'm so excited because today's topic is marginal zone b-cell lymphoma. So let's get started.
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I've told you like a million times before, hematological malignancies are leukemias, lymphomas, and myeloma. Lymphoma is a solid tumor of the immune system, not only the lymph node, but spleen, mucosal-associated lymphatic tissues, thymus, etc. Lymphoma used to be classified as Hodgkin's and non-Hodgkin's. Now the new classification is lymphoma has three subtypes: Hodgkin's, b-cell, and t-cell. Just kind of the same, but it's okay. Non-Hodgkin's lymphoma is either aggressive or indolent. We have talked about the diffuse large b-cell lymphoma, Burkitt's, and mantle in previous videos. All of these are aggressive. Today's topic is marginal zone b-cell lymphoma, and this type is indolent.
Indolent lymphomas or low-grade lymphomas occur in older patients, fewer B symptoms, higher stage at presentation. But today's topic, marginal zone lymphoma, is an exception. It can present in earlier stages, sensitive to chemo, of course. Median survival rate is long, and it can change to aggressive lymphoma. And MALToma, which is today's topic, can change into diffuse large b-cell lymphoma, which is high-grade or aggressive.
In case you're wondering where is the margin, so you have to watch my previous video on the anatomy of the lymph node to get an idea. So here is the follicle of the lymph node. The lymph node has a cortex, then paracortex, medulla, and medullary sinuses. The cortex has three regions: the germinal center in the middle, the mantle, and the margin. So where is marginal zone lymphoma? It's here in the cortex. As you know, has the B cells. The paracortex has the T cells. That's why marginal zone lymphoma is a b-cell lymphoma because all of this is still in the cortex. By using Aristotle's deductive reasoning, we start with two premises: number one, since the margin is in the cortex, since the cortex has B cells, conclusion: marginal zone lymphoma is a b-cell lymphoma. Voila!
Marginal zone lymphoma is a b-cell non-Hodgkin's lymphoma. Yes, it's indolent, and this is different from mantle lymphoma, which is aggressive. So marginal zone, indolent; mantle cell lymphoma, aggressive. Median age of presentation is between 60 and 65. Could be nodal, extranodal, or splenic. But you might ask, isn't splenic like the same as extranodal? Yes, but spleen is significant here, so we give it a separate category. Okay, kiddo.
Risk factors: we have autoimmune diseases such as Sjogren's syndrome can lead to salivary gland MALT lymphoma. Hashimoto can lead to thyroid MALToma. Chronic inflammation due to infection that Borrelia burgdorferi can lead to cutaneous MALToma. H. pylori can lead to gastric MALT lymphoma. Hepatitis C virus can lead to splenic MALT lymphoma. Chlamydia C. turkey or C. or whatever can lead to conjunctivitis, which will lead to ocular MALToma or ocular adnexal marginal zone lymphoma. Same thing. Cool.
There are three types of marginal zone lymphoma: nodal, extranodal, and splenic. Nodal affects the lymph nodes, yes, the margin of the follicle of the lymph node. Extranodal can affect the stomach, intestine, orbit, lungs, thyroid, skin, salivary glands, CNS, urinary bladder, or the kidney. Wow, it can affect like a wide variety of organs. Splenic affects on the spleen.
Clinically, patients could be asymptomatic, and depending on the subtype, we have different sets of symptoms. Plus, B symptoms can be in either one of these. These symptoms are fever, weight loss, which has to be unintentional and more than 10% of the total body weight, and drenching night sweats. So nodal will have enlarged, palpable, painless lymphadenopathy. Extranodal, depending on the location: gastric MALToma, nausea, vomiting, anemia, and abdominal mass or a gastric mass. Salivary MALToma can lead to salivary gland mass. Thyroid MALToma, mass. Lung MALToma can lead to dysphasia or difficulty swallowing. Splenic only to splenomegaly and abdominal discomfort because the spleen is gonna press on the diaphragm and it's gonna press on the abdomen, and it's just a mess. Marginal zone b-cell lymphoma can have a leukemic phase, which makes sense because non-Hodgkin's lymphomas have extranodal involvement, and leukemic phases are common.
How to diagnose marginal zone b-cell lymphoma? We need a biopsy of what? It depends. If you have the nodal subtype, biopsy the lymph node. If you have the stomach subtype, biopsy from the stomach, from the salivary gland, from the spleen. And you will find malignant cells in the margin of the lymph node in cases of nodal marginal zone b-cell lymphoma. Immunohistochemical stains and flow cytometry will have CD19 and 20 positive because it's a b-cell lymphoma. BCL-2 can be involved. Increased LDH and increased beta-2 microglobulin, similar to multiple myeloma. If you have gastric MALToma, you need a stool sample to diagnose H. pylori because it's a trigger for marginal zone b-cell lymphoma, called antigen stimulation. If you have cytokine, you need a bone marrow biopsy to determine the cause. Staging: physical exam and CT scan, PET scan can help with diagnosis and follow-up. To diagnose any lymphoma, never use fine needle aspiration. You need either an excisional biopsy or a core needle biopsy. Either one is fine.
The prognosis of marginal zone b-cell lymphoma is relatively good. Why? Because it's an indolent, low-grade lymphoma. Refer to Ann Arbor classification that we have discussed before to know like the prognosis. The higher the stage, the worse the prognosis.
Treatments: no symptoms, no treatment. Why? It's an indolent lymphoma. We use the watch and wait or observation approach. If you have Hep C, treat the Hep C, and the lymphoma should go away. Wonderful. If you have H. pylori, treat the H. pylori, eradicate it, and the lymphoma should go away. Perfect. So here is an example of a lymphoma that can be treated with antibiotics. Did you know that some cancers are treatable using antibiotics? Yes, indeed, and marginal zone b-cell lymphoma is a great example. If you have a local disease, radiate. Diffuse disease, radiation is not gonna be beneficial. So we use single-agent chemo. Again, it's an indolent lymphoma. Start with a single agent such as fludarabine. Also, you can use lenalidomide or bendamustine. You can add rituximab, and as you know, research have shown that adding rituximab is very good. If the lymphoma, like the marginal zone lymphoma, has transformed into diffuse large b-cell lymphoma, which is an aggressive, high-grade lymphoma, you need to be aggressive and use combination chemotherapy such as the R-CHOP therapy discussed in previous videos.
I'm not done yet. We have a case at the end of the video, so stay tuned.
Question of the day: How to eradicate H. pylori infection? Let me know down below in the comments. Pause and comment. And here is a homework for you: search the topic mechanism of action of lenalidomide. If you are one of these folks that are like A+ students, you're one of these people.
Sjogren's syndrome can lead to either extranodal salivary gland marginal zone lymphoma or MALToma, or the same Sjogren's can lead to diffuse large b-cell lymphoma. And as you know, that the marginal zone lymphoma can transform into diffuse large b-cell lymphoma. Both of which are non-Hodgkin's lymphoma. So Sjogren's syndrome can involve like enlargement of salivary glands or parotid glands on both sides, okay? Like right parotid and left parotid. And this is okay. If it has an enlargement of only one gland, be very suspicious that this is lymphoma. Which kind of lymphoma? It's non-Hodgkin's lymphoma. Which subtype? Could be either one, and you need a biopsy to differentiate. Again, don't use a fine needle aspiration. Use a core needle biopsy.
Hashimoto can lead to extranodal thyroid MALToma or diffuse large b-cell lymphoma. Again, both of which are non-Hodgkin's. So here is a case for ya. Sixty-six-year-old male comes to you complaining of epigastric pain. It started eight months ago. The pain has a burning quality. It increases at the end of the day, especially after meals, wearing tight clothes, or lying flat in bed at night. An upper endoscopy with a biopsy was performed, and here are the results. On the biopsy, you see gram-negative rods, okay, in the stomach, as well as malignant lymphocytes in the lymphatic follicles with no invasion to other local structures. LDH was high. Immunohistochemistry, you find CD19 positive and CD20 positive.
Question number one: What's the most likely diagnosis? Is it peptic ulcer disease, mantle cell lymphoma, marginal zone b-cell lymphoma, adult t-cell leukemia, or lymphoma?
Second question: How should you treat? Gastrectomy, antacids, proton pump inhibitors plus amoxicillin plus clarithromycin, or radiation plus R-CHOP? Let me know the answers to both of these questions down below in the comments section.
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