Thursday April 12, 2001



Thursday April 12, 2001

Pathology 9 a.m.

Dr. David L. Morgan

Masters of the Universe: Rishi/Zee

Dr. Morgan cited a classification system of lymphomas from a recent article in the New England Journal of Medicine that classified lymphomas as “good ones”, “not so good ones”, “bad ones”, and “ones that aren’t what they seem”. That’s easy! Unfortunately, that’s not going to be on the test. So, don’t study this … please. Unfortunately, since I didn’t put a disclaimer in front, that means you have read it and now you are doomed to never forget it, all the while forgetting other minutiae that WILL be on the exam. Sorry.

Proofers note (aka The guru of underlining) here we go again ,only look at the bold font and nothing but the bold. All other stuff is to be ignored. Otherwise you will use up the limited neuronal space we have and so desperately need more of. I have underlined things that might be helpful in understanding this material, are interesting or just cause I felt like it. Then again you shouldn’t really be reading this stuff it is not in bold! As Rishi would say by the power of grey skull let us begin!!!

I. Hodgkin’s Disease

A. Clinical presentation: Arises in a single lymph node or a single lymph node region with painless lymphadenopathy. Presents like a high grade malignant lymphoma, which should be present in the ddx of patients with these symptoms

1. Spreads to neighboring nodes or contiguous lymph nodes

2. Patients may also present with system symptoms like fever, nightsweats (also found in malignant lymphomas)

3. Average age of diagnosis: 32 years

4. Good news!! Aggressive chemotherapy and radiotherapy make Hodgkin’s a very curable disease

5. Dr. Hodgkin … I mean Dr. Morgan showed a picture of a patient with a severe lymphadenopathy

6. So how do we distinguish Hodgkin’s from malignant lymphomas?

a. Therapy for each pathology is totally different, so it’s important to diagnose correctly

b. We want to look for the diagnostic Reed-Sternberg cells mixed with a non-neoplastic background of inflammatory cells. In fact, the malignant cells are in the minority and may be difficult to see among the inflammatory cells (lymphocytes, plasma cells, eosinophils, and macrophages). Fig. 15-24 A

B. Morphology of Hodgkin’s

1. The different types of Hodgkin’s disease can be classified based upon differing proportions of the various inflammatory cells found in the lesion

2. The diagnostic Reed-Sternberg cells, “classically”, are large cells with amphophilic (purple-staining) cytoplasm and a mirror image binucleate or bilobed nucleus. He showed a slide of this. Important things to note are the large size of the cell, the purple cytoplasm, the mirror image nuclei and the rather large nucleoli giving these cells the classic “owl eye” appearance (Oh yeah! I hate the classic “owl eye” appearance. It seems every other histo slide we look at has an “owl eye” appearance! Not so classic, is it! Don’t forget “owl eye”!)

3. Multinucleate or mononuclear Reed-Sternberg cells are also typical of the various subtypes of Hodgkin’s but are in and of themselves not diagnostic in the absence of the classical RS cells described above, so we definitely need to find these to make the diagnosis. He showed a slide of a mononuclear RS cell. However, this slide may only appear as a mononuclear cell due to plane of the cut that was made in preparing the slide. We may very well be looking at a classical binucleate RS cell. Who knows? I certainly do not.

4. We may also find “lacunar cells”, which display a retraction artifact when we (well, more like “they” since I will never do this.) fix them in formalin. The cytoplasm shrinks away leaving a nucleus in a hole of wispy nucleus. If you will, this looks like a nucleus in a “lake”. Hence, “lacunar”. These cells are typical of a subtype of Hodgkin’s disease known as nodular sclerosing Hodgkin’s disease.

5. They may also find a subtype of cell which are very large with very convoluted nuclei exhibiting vacuolated chromatin called lymphocyte/histiocyte or L & H cells. Dr. M. prefers the term popcorn cells because they look like popcorn ( I prefer the term “popcornular” or maybe, “owl’s eye”!). These are typical of the subtype of Hodgkin’s known as lymphocyte predominant.

6. Dr. M. proceeded to show slides of the following:

a. classic Reed-Sternberg cell

b. Multinucleate Reed-Sternberg cell

c. Lacunar cell: shrunken with empty space around it. His words, not mine.

C. Classification: prognosis of Hodgkin’s can be determined by histological classification and extent of the disease. Well actually, nowadays, extent of the disease is solely used to determine prognosis. But we, I mean “they”, must be familiar with the various histological subtypes in order to more accurately diagnose Hodgkin’s disease, lest they call it malignant lymphoma instead. “We” must be familiar with it so that we can answer multiple choice questions about it on various exams, standardized or otherwise. There was a Rye conference where the classification was standardized. So, the classification system for Hodgkin’s disease sometimes carries the monniker, “Rye Classification” (see notes). Anywho, let’s get it on!

1. Lymphocyte predominant

a. the inflammatory cells in the background in this subtype are predominantly small mature lymphocytes, giving a very homogenous appearance. They must be careful not to misdiagnose this as small lymphocytic lymphoma.

b. One way they can stay clear of making this mistake is by spotting the infamous “popcorn” cells we discussed above, which will prompt them to look for the diagnostic classic Reed-Sternberg cells. 15-24 D

c. Other identifying criteria for this subtype of Hodgkin’s include: Diffuse to vaguely nodular infiltrate of mature lymphocytes, (mostly B cells) [ Still sounds like small lymphocytic lymphoma? Well remember that small lymphocytic lymphoma is CD5+ for B cell antigens and may exhibit monoclonal restriction. Dr M. said we don’t have to worry about these details. Whatever.] very few eosinophils, neutrophils, or plasma cells, very minimal or absent fibrosis/necrosis, few RS cells, and numerous “popcorn cells”.

d. The popcorn cells are CD20 positive and Leu-MI/CD15 negative. ( only one that is cd15 negative) These are opposite staining patterns as those seen in RS cells of other types of malignant lymphoma

e. Typically affects males under 35 years of age with localized disease predominating

f. Excellent prognosis, even predating better chemotherapy

2. Mixed cellularity

a. Often referred to as the “garbage can” of Hodgkin’s disease, when things can’t fit in the other subtypes, they dump it in this category

b. Majority of reactive mature B cells are of the T-cell type, different than lymphocyte predominant.

c. May see some eosinophils, plasma cells, and benign histiocytes.

d. May see small areas of necrosis and fibrosis

e. Won’t have any trouble finding the classic Reed-Sternberg cells, which, in this form, are Leu M1/CD 15 positive, unlike the RS cells found in the lymphocyte predominant type

f. Again, malignant lymphocytes are in the minority in relation to the reactive inflammatory cells.

g. Lymphocyte predominant subtype may indeed be a transition between malignant lymphoma and Hodgkin’s disease. More later.

h. Showed a slide of mixed cellularity subtype demonstrating all the above-mentioned properties

i. Males under 35 predominate

j. More often disseminated with systemic symptoms and worse prognosis

3. Lymphocyte depletion

a. Relative paucity of lymphocytes and histiocytes.

b. Few classical Reed Sternberg cells.

c. Lots of necrosis and fibrosis

d. Two variants, diffuse fibrosis and reticular: diffuse fibrosis variant characterized by hypocellular lymphnode with disorderly background of nonbirefringent proteinaceous fibrillar material in the background. Reticular variant characterized by cellular node with few classical Reed-Sternberg cells (Leu-M1/CD15 positive), many large pleomorphic RS variants called sarcomatous variants.

e. Occurs more often in older patients with disseminated disease and systemic symptoms

f. Worst prognosis, even with modern chemotherapy

4. Nodular sclerosis

a. clinically and histiologically distinct from the other forms.

b. Will see lymphocytes of the T-cell type, plasma cells, and numerous eosinophils.

c. Few classical Reed-Sternberg cells (Leu-M1/CD15 positive)

d. Many RS variants such as lacunar cells [see B.4.]

e. Variable degrees of fibrosis with dense birefringent bands of collagen dividing the node into circumscribed cellular nodules, typical of nodular sclerosis. Dr. M. compared the nodules in the “empty space” of protein to the lacunar cells also sitting in an “empty space”. Did this analogy strictly for mnemonic purposes only. Don’t memorize this unless it helps.

f. Most common form of Hodgkin’s disease and the only form more common in women.

g. Tends to occur in lower cervical, supraclavicular, and mediastinal lymph nodes in young patients.

h. Excellent prognosis

D. Etiology and pathogenesis

1. Currently felt that the RS cells and their variants ( represent the malignant cells in the disorder.

2. The associated inflammatory cell infiltrate is believed to be a repsonse to cytokines produced by the malignant cells, including IL-5, IL-4, tumor necrosis factor (, GM-CSF, and TGF-(. IL-5 correlates with eosinophilia ( characteristic of mixed cellularity and nodular sclerosis subtypes). TGF-( correlates with fibrosis production, found most commonly in nodular sclerosis subtype.

3. Molecular analysis has demonstrated variability amongst the subypes with RS cells of some being positive for B-cell associated antigens (lymphocyte predominance) and others being of T-cell origin. Dr. M. again mentioned theory that lymphocyte predominant subtype is a transition from malignant lymphoma, which is also of B-cell type, to Hodgkin’s disease. Some cases have shown clonal abnormalities suggesting monoclonality; light chain restriction in B-cells and T-cell receptor gene rearrangements, also seen in malignant lymphoma. Epstein Barr virus infection has been proposed to be a causative agent.

E. Prognosis

1. With modern treatment protocols, tumor burden (stage) rather than histological subtype is the most important prognostic variable. Lymphocyte depletion subtype is an excpetion to the rule.

2. Currently, the 5-year survival reate of patients with stages I and IIA is close to 90% and many can be cured. Even with advanced disease (stages IVA and IVB), 60 to 70% five-year disease-free survival can be achieved.

3. However, survivors have an unfortunate increased risk of developing therapy-induced malignancies including acute non-lymphocytic leukemias, lung cancer, malignant lymphoma, breast cancer, gastric carcinoma and melanoma due to chemotherapeutic agents

F. Slides he showed

1. Classic RS cell

2. Mononuclear variant of RS cell

G. Clinical Staging of Hodgkin’s and malignant lymphomas

1. Based on a system decided in Ann Arbor, Michigan

2. Based on physical examination, lymphangiography, chest x-ray, liver and bone scan, bone marrow biopsy, and computed tomography

3. In reality, they first do a physical examination and then a bone marrow study because by defintion, if there is bone marrow involvement, the patient is in stage 4 disease and there is nothing we can do to help. Furthermore, bone marrow biopsy is a fairly beningn procedure.

4. If the disease appears localized, a staging laparotomy may be performed with visualization and possible biopsy of retroperitoneal lymph nodes, liver biopsy, and splenectomy.

5. With today’s modern imaging techniques, staging laparotomy has become obsolete

6. Now, they usually do physical examination, bone marrow studies, and radiological stuff.

7. He didn’t go over the “self-explanatory” listing in the text and notes of the various stages. Things to know: increasing numbers mean increased involvement (Oh! That’s why I got all those questions wrong on the last Path test!!), stage IV indicates bone marrow involvement, each stage is subdivided into A and B. “A” indicated absence of and “B” indicated presence of systemic symptoms such as fever, night sweats, and/or unexplained weight loss.

Plasma Cell Dsycrasias

A. Clonal expansion of immunoglobulin-producing plasma cells. These are malignancies in which the cells have become stuck at the plasma cell stage of lymphocyte transformation. The monoclonal immunoglobulin produced by these plasma cells and/or its fragments (heavy or light chains) produce a characteristic paraprotein “spike” or M (monoclonal) component on serum or urine protein electrophoresis.

B. Dr. M. showed a slide of a serum protein electrophoresis. It displays bands representative of various serum proteins. The major bands we see are referred to as the albumin, alpha-1, alpha-2, beta, and gamma bands. The gamma band represents the various immunoglobulins found. Since there are various polyclonal immunoglobulins (IgG, IgA, IgM, etc.) to be found, the gamma band is normally broad. However, sometimes, they may see narrow M “spikes’ which indicates a predominance of a single type of monoclonal immunoglobulin such as IgG (most common), IgA, or IgM (rarely IgD, or IgE). The unique specificity of the monoclonal immunoglobulin may be specific for nothing or may represent an autoantibody.

C. Another finding may be decreased concentration of normal polyclonal immunoglobulins due to the plasma cells with the monoclonal immunoglobulin in question “crowding out” the normal plasma cells. Dr. M. then reminded us that the monoclonal immunglobulins may not be intact but may represent only certain light chains or heavy chains or non-functional combinations of both.

D. Bence-Jones proteins (free light chains) are rapidly cleared by the kidneys and concentrated in the urine. Thus, we may have to depend on urine protein electrophoresis as opposed to serum protein electrophoresis in order to detect them. Irreversible damage to renal tubular epithelia may ensue on deposition of monoclonal immunoglobulin on the epithelium. Tissue deposition of monoclonal immunoglobulin light chains may lead to devlopment of amyloidosis. We can treat this condition by plasmapharesis or treating the underlying multiple myeloma.

E. Dr M. showed an immunofixation gel electophoresis, which determines whether the paraprotein spike represents a monoclonal immunoglobulin and characteristizing the immunoglobulin if indeed that’s what it is.

1. Dr. M. showed a normal immunofixation electophoresis. It has wells designated, as before, albumin, alpha-1, alpha-2, beta, and gamma. The gamma wells each have an antihuman antibody to the heavy chains of various classes of immunoglobulin (IgG, IgA, IgM, IgD, IgE) and various light chains (( and (). In the normal patients, we see the various immunoglobulins form a broad band with IgG representing the greatest/strongest band. IgA unusually travels farther than the alpha bands, thus representing another (rather unusual) place to look for M spikes. The normal ratio of ( to ( light chains seen is 2:1.

2. Now, we move on to the patient. We see a dark band among the general proteins and we see that band corresponds to IgG among the gamma bands. We also observe a decrease in amount of other immunoglobulins, typical of multiple myeloma. Also seen travelling with the IgG band is a band corresponding to the ( light chain. So, a viable diagnosis would be multiple myeloma expressing intact immunoglobulin with IgG and ( chains.

3. Thought question: If we observed another ( band in the electrophoresis that didn’t correspond to the other IgG band or the other ( band, what would we be looking at? We would be looking at free light chain disease superimposed on the underlying multiple myeloma since the second ( band didn’t have a corresponding IgG band of its own. Now, the possibility of renal complications is known

4. Dr. M. showed a picture of the liver affected with amyloidosis. Among the hepatocytes, a pink-staining, proteinaceous material is observed. This is amyloid. The monoclonal immunoglobulins, again, may act as autoantibodies making these diseases complicated by disorders such as hemolytic anemia, or bleeding [Remember the type of hemophilia which was a result of a lymphoproliferative disorder, such as malignant lymphomas or plasma cell dyscrasias?]

II. Multiple Myeloma

Most common plasma cell dyscrasia

A. The “myeloma” part doesn’t refer to granulocytic precursors but to the bone marrow in general which suffers “multiple” punched out lesions. More later.

B. The peak incidence is between 50-60 years of age. Both sexes are affected equally

C. Monoclonal IgG seen most frequently (55%), followed by IgA or light chain only (25% each) IgM, IgD, IgE are rarely involved.

D. Quantitation of monoclonal immunoglobulin in the paraprotein spike usually demonstates serum levels greater than 3 g/dL. A poor prognosis (irreversible kidney disease) is associated with urine Bence Jones protein levels greater than 6 mg/dL

E. Infiltrates of mature appearing plasma cells may produce multiple “punched out” lytic bone lesions or generalized osteoporosis, both leading to pathological fracture.

1. Hypercalcemia from bone resorption may produce confusion, weakness, lethargy, constipation, and polyuria.

2. Osteoclast induced bone resorption is stimulated by tumor produced cytokines including TNF-(, IL-1,IL-6, and macrophage colony stimulating factor (M-CSF).

3. Showed a x-ray of skull. When you see something like this, you should think of the two M’s, multiple myeloma or metasteses, which produce multiple punched out lesions like this. In fact, the multiple punched out lesions aren’t even seen in the majority of those afflicted with multiple myeloma (max 50% incidence, others having only generalized osteoporosis).

4. Showed a slide of pathologic vertebral fracture due to multiple myeloma. This is a quite common clinical picture. Multiple myeloma itself is a quite indolent disease. So, the patient will be asymptomatic for years and then first come to your office with rapid onset of paralysis.

F. Although the malignant cells have more or less mature plasma cell morphology and function, this is believed to represent a disease of hematopoietic stem cells. The reason for this belief lies in the fact that myeloma cells not only express plasma cell-associated antigens on their surface but those of other cells as well, including megakaryocytes, early B-cells, and granulocytes.

G. Suppression of normal immunoglobulins may lead to recurrent infections with encapsulated bacteria (e.g. pneumococci). This occurs via malignant cells “crowding out” the good plasma cells that could actually fight infections

H. Another complication is hyperviscosity seen in about 7% of patients, most commonly in those with monoclonal IgA due to its ability to polymerize into larger molecules contributing to viscosity in the blood stream. Manifestations include retinal hemorrhages, prolonged bleeding, and neurological changes such as headache, dizziness, deafness, and stupor. We can treat this with plasmpharesis to remove the IgA from the blood stream.

I. Peripheral blood findings include normochromic, normocytic anemia (the anemia of chronic disease), rouleaux formation, and rarely leukemic involvement (plasma cell leukemia, which results in late stages of the disorder where there has already been so much proliferation and so much bone marrow destruction that they start leaking out)

1. Side note on rouleux formation: rouleaux formation, the clumping of erythrocytes, occurs due to a decrease in the repulsive electrostatic zeta potential normally found between erythrocytes due to all of them having a negative charge. This reduction in the negative charge, and hence repulsion, is due to an increase in the ratio of surface protein to red cell count, since protein coating the outside of an erythrocyte decreases its negative charge for some reason. Hence, conditions that increase the amount of ambient protein ( i.e. multiple myeloma, inflammatory disorders) or decrease the amount of red blood cells (i.e. anemia) will lead to rouleaux formation. Rouleaux formation can be measured by erythrocyte sedimentation rate (ESR) in order to possibly monitor inflammatory conditions. However, measuring acute phase reactants such as C-reactive proteins is a better way to measure rouleaux formation.

J. Bone marrow examination discloses increased plasma cells in a diffuse or nodular pattern. Must be discriminated from causes of reactive plasmacytosis.

1. Plasma cells normally don’t make up more than 6-10% of the bone marrow cells. In any sort of chronic or inflammatory condition, they can increase. In patients with AIDS, plasma cells make up 20-30% of the marrow cells. However these cells are normal plasma cells and not malignant plasma cells. So how do we tell the difference?

2. We will have to look for morphological changes. The more abnormal the plasma cells look, the worse the prognosis. Normal plasma cells have quite a bit of dark blue cytoplasm, a clear zone around the nucleus known as a a Hoff zone (a golgi apparatus), an eccentric nucleus with heavily clumped chromatin with clock-faced appearance and peripheral condensation of chromatin around the margins of the cell. Showed a slide of this. Abnormal plasma cells of multiple myeloma look “constipated” “us medical students know nothing about this word”( with numerous cytoplasmic globules and vacuoles of immunoglobulin. Some multiple myelomas, in fact, consist of abnormal plasma cells that can’t secrete the monoclonal immunoglobulins in their vacuoles and there is no extraneous M proteins or the “spikes” that they cause. Abnormal plasma cells may also be binucleate. He showed a slide of this. Dr. M. showed a bone marrow slide. He asked us to note that there wasn’t significant hypercellularity but there were noticeable clumps of cells. Looking at these at higher power, we note these cells have rather large nucleoli.

3. We can also look at the distribution of the plasma cells. Normal plasma cells will congregate around capillaries of bone marrow during a condition such as an inflammatory disorder. Plasma cells of multiple myeloma will not be localized around these blood vessels but will proliferate in a diffuse or nodular pattern. What nails the diagnosis is when we stain for ( and ( chains and find in a nodule of plasma cells in the bone marrow that they all stain for ( chains when 2/3 of them should be staining for ( instead. Thus, we know it is multiple myeloma for sure since the mere existence of hypoglobulinemia due to multiple myeloma in which there is no secretion of monoclonal immunoglobulins by the abnormally secreting malignant plasma cells described above could be caused by other conditions.

K. Sometimes the proliferation of plasma cells is contained within a single tumor. This is known as a solitary plasmacytoma, which is an infrequent variant consisting of an isolated neoplastic mass of plasma cells in the bone or soft tissue. Extraosseous plasmacytoma is often cured by surgical removal alone. Osseous plasmacytoma typically progresses to multiple myeloma regardless of therapy; however, this may not occur for up to 20 years, in which time the more commonly older patient may have contracted a more harmful condition (heart disease, diabetes, etc.).

L. Referred to as Heavy-chain or Light-chain disease in the absence of demonstrable associated monoclonal light chains or heavy chains respectively. Non-secretory myeloma (described above in J.2.) occurs rarely.

M. Associated with chromosomal abnormalities, most commonly chromosome 14. Those associated with chromosomal abnormalities have a worse prognosis.

N. More than anything, prognosis depends upon the stage of advancement at time of diagnosis. Again, this disease is very indolent and those afflicted will be asymptomatic for quite a long time before they present. When they do present, they will present with a high stage of the disease with bone marrow involvement and subsequent anemia, thrombocytopenia, etc.

O. Patients with many bony lesions, if untreated, rarely survive longer than one year. In advanced cases, chemotherapy with alkylating agents prolongs median survival to 2-3 years. Actually, this is no longer true. Beginning five years ago, newer treatments have greatly helped in our ability ot treat this disorder. They now see patients who have successfully removed all the multiple myeloma from their bone marrow with no evidence of remission. Yaaayyy!!! Of course, they don’t know exactly how much they’ve bettered these patient’s prognosis since the newer treatments have only been around for five years. Still, if we’re lucky, they may be on the road to curing multiple myeloma.

P. Increases in serum IL-6 is associated with poor prognosis. Clinically irrelevant so not important. Whatever.

Buh …Bee … Buh … Bee … B-Beeeep … That’s all folks!!

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