Q. I need help with this question from Robbins:

15 year old boy with fever of 10 days. Petechial hemorrhages on trunk and extremities. CBC shows Hg 13.2, Hct 38.9%, MCV, 93, plt ct 175,000 and WBC ct 1860 with 1% segs, 98% lymphs, and 1% monocytes. BM biopsy shows no abnormal cells. What’s the diagnosis?

The answer was overwhelming bacterial infection! It said you are supposed to multiply the percentages in the differential by the total WBC to get absolute values. Any tips for reading WBC counts and diffs? They are so daunting! Would it possibly be included in The Complete But Not Obsessive Hematopathology Guide? I’ve definitely gotten some questions right just from reading pathologystudent though! Such as the difference between a CML and leukomoid reaction!

A. This is a great question! Yes – there is quite a bit about the diff in The Complete Hematopathology Guide. You might just start by downloading the Top 10 Anemias if you haven’t already (it’s free) – I have a bit in there about normal CBC values. I think once you understand the diff and the CBC, it becomes a lot less overwhelming. You do need to know how to multiply the percentages to get the absolutes…but you definitely don’t have to do that on every case. And for most cases, it’s fine to just do a ballpark figure.

Why do you need to look at absolute counts?
The reason you need to look at absolute counts is because if you just look at percentages, you could mess up. Let’s say you have 60% neutrophils in a particular patient. You might take a quick look at that and go, oh, yeah, that looks fine. But if you don’t take the time to find out the absolute neutrophil count, you could be missing something. If the WBC count in that particular patient is very low, say 1.5 (normal being 4-11), then the patient would have a low number of neutrophils even though the percentage of neutrophils is normal.

So we had this lecture on malaria on Thursday, and I decided that we needed a little object lesson to go along with it. Something interesting, and preferably tasty. It was a joint pathology + pharmacology lecture, so it needed to tie both of those together too.

I ended up making cookies that looked like malaria-infected red cells (photos below). And we had some tonic water to go along with the cookies (tonic water contains quinine, a drug that is still used today in the treatment of malaria). That way, the students could eat all the malaria-infected cookies they wanted, but they would be protected with quinine prophylaxis.

Here are the stages of the organism that ended up getting depicted in cookie form:

1. Gametocyte (see the photo above). The gametocyte is the sexual form of the plasmodium organism. In most species, it’s just a blobby thing. But in plasmodium falciparum, it’s a curvy, banana-shaped thing.

Which brings me to the title of this post. I never knew this (and hence could never remember which species had the banana-shaped gametocytes) – but falciparum comes from two Latin words: falx (which means a curve-shaped thing) and parum (which means to give birth to). That’s why the falx cerebri in the brain is named that way: it’s a curve-shaped structure.

The gametes in plasmodium falciparum (but not in other species!) are curved structures (falx) that are the sexual forms (give birth to) of the organism. Cool, huh? I don’t for sure whether that’s the reason the species was dubbed “falciparum” but it’s a pretty amazing (and fortuitous) coincidence if it was unintentional.

There you go: now you will always remember that falciparum is the species with the curved gametocytes.

2. Ring form (trophozoite). This is the first manifestation of the plasmodium organism in the red cell. All species have ring forms. They are kind of cute: little bluish circles with one or two reddish-purple chromatin masses.

3. Schizont. This form comes after the trophozoite. It is actually a whole bunch of little baby plasmodia all grouped together in one cell. Eventually, the red cell ruptures, and all the little babies (which are called merozoites now) come out, and start infecting other red cells. Some of the merozoites turn into gametocytes, which wind up in the mosquito, where they reproduce sexually and complete the life cycle of the plasmodium.

4. These cookies (below) are sickle cells, not plasmodial forms. I made them to remind the class that patients with sickle cell disease have a natural protection against malaria. If a patient with sickle cell disease does get infected, the infection is usually less severe, and is cleared more rapidly. Which explains why areas endemic for malaria have the highest incidence of sickle cell disease.

Q. I wanted to check a fact with you because my friend and I were confused by something in First Aid, and it wasn’t listed in one of the errata for the new edition. Under non-megaloblastic macrocytic anemias, it lists liver disease, alcoholism, reticulocytosis, and drugs such as 5FU and AZT and hydroxyurea as potential etiologies. Is this right?

A. Huh. In general, I like First Aid – but there are some things that are just plain wrong. Let’s take a look.

Okay, so we know that antinuclear antibodies are seen in many different autoimmune diseases (including lupus).But how do you make antibodies against something (a nuclues) that is not “visible” to the immune system? And once you’ve made the antibodies, how do they cause problems?

How are these antibodies made?
It turns out that ultraviolet radiation (the sun) and other environmental insults lead to the apoptosis (programmed death) of cells. As these cells die off, they bust open and their nuclei are exposed. If you don’t completely clear away the dead cells, the nuclei will sit around for a while. In lupus, there is an abnormality in the process of self-tolerance (where the immune system learns to recognize the body’s own antigens, and any immune cells that react against self are deleted). So patients with lupus can (and do) make antibodies against these cell nuclei.

Complexes of the nuclear antigens and antinuclear antibodies are formed. These complexes bind to Fc receptors on B cells and dendritic cells, further stimulating B cells to make autoantibodies as well as immune-system-enhancing cytokines (which can cause more apoptosis). So it’s a nasty self-perpetuating cycle; once you get going, it’s hard to turn off the cycle.

How do the antibodies cause problems?
Most of the organ-based symptoms in lupus (like kidney disease and skin disease) are caused by immune complexes. Anti-DNA antinuclear antibodies are virtually diagnostic of lupus; you can find DNA-antiDNA complexes all over in patients with lupus. It’s not a good idea to have these immune complexes around, because they can stick to endothelial cells in vessels, where they call in inflammatory cells and complement, both of which are damaging to the vessel wall. This process is called a type III hypersensitivity reaction – and it happens in lots of other diseases besides lupus too.

Sometimes, you can see evidence of the antinuclear antibodies in tissues. Antinuclear antibodies will bind to any damaged cells within a particular organ or tissue, causing the chromatin to become more smooth-looking. You can see these weird-looking nuclei (called LE, or lupus erythematosus, bodies) under the microscope. Sometimes, you can even see phagocytic cells (neutrophils or macrophages) eating up these denatured nuclei. These dead-nucleus-containing phagocytes are called LE cells, and you can see one in the image above (the dead nucleus is the curvy, bland-looking one on the right). In fact, in the olden days, the lab would take a tube of blood and shake it up (to disrupt the cells, expose the nuclei, and allow the patient’s antinuclear antibodies to bind) as a test for lupus! If you saw LE cells, that would be indicative of lupus.

The design

Our final product is what you see here: our logo cells on the front (that’s a blast from a case of acute promyelocytic leukemia) and Pathology Student/Living the Dream on the back. We put the Living the Dream part in Latin (Somnium vivens) because it’s so much cooler that way. Most students felt that having the cells alone on the front makes for an intriguing shirt with a path-geek vibe. As Isaac said, people will see the front of the shirt and go “Hey, that’s a cool shirt. This person has their life together.” Plus it gives you a chance to say, “Why thank you. It’s from Pathology Student, and I am living the pathology dream.”

The shirt

The t-shirt itself is a heavyweight, pre-shrunk 100% cotton tee (white, short sleeves). Sizes are:

• Small (chest width 18″, length 28″)
• Medium (chest width 20″, length 29″)
• Large  (chest width 22″, length 30″)
• X-large (chest width 24″, length 31″)

To get a decent price, we need to order in batches of 150. So for this first batch, I’d like to get pre-orders before I go ahead and place the order. The pre-order price will be $13.50 (plus $4.50 shipping, for US orders), which is a little lower than the future regular price (which will be a little over $15.00).

To Pre-Order a Shirt

The pre-order price is $13.50 (plus $4.50 shipping, for US orders), which is a little lower than the future regular price (which will be around $15.00). The print shop is estimating a delivery date around May 7. To order a shirt, choose your size and click the add to cart button. If you’re outside the US, choose your country and postal code, and shipping will be calculated for you.

Systemic lupus erythematosus (SLE) is a multisystem, autoimmune disease. It’s characterized by the formation of many different autoantibodies, the most notable of which are antinuclear antibodies. These antibodies are useful for diagnosis, and they also play a big part in the pathogenesis of the disease.

Antinuclear antibodies
Antinuclear antibodies are just what the name implies: antibodies against specific antigens within the cell nucleus. They can be grouped into four categories: 1) anti-DNA antibodies, 2) anti-histone antibodies, 3) antibodies against non-histone proteins bound to RNA, and 4) anti-nucleolar antibodies.

Antinuclear antibodies in general are found in many different autoimmune diseases (like systemic sclerosis and rheumatoid arthritis). Antibodies to double-stranded DNA and a particular antigen called the Smith (Sm) antigen, however, are virtually diagnostic of lupus. Patients with lupus have other, non-antinuclear antibodies too – but here we’re just talking about the antinuclear ones.

How a FANA works
Autoantibodies are usually detected using fluorescent antinuclear antibody (FANA) testing. You can use other methods – like enzyme-linked immunosorbent assay (ELISA) – but immunofluorescent microscopy is the gold standard method. In this method, the lab takes a slide coated with fixed, permeable cells (bought from a manufacturer) and adds some of the patient’s serum to that slide. The serum is allowed to incubate, and is then washed off.

At this point, if the patient has antinuclear antibodies, they will be bound to the slide. You can’t see them, of course, so a second antibody with a fluorescent tag (also bought from a manufacturer) is then applied to the slide, allowed to incubate, and washed off. If the patient has antinuclear antibodies that are bound to the cells on the slide, these antibodies will now fluoresce under the microscope.

This test is cool because you can tell not only if antibodies are present (by seeing green stuff on the cell nuclei) but also what kind of antibodies they might be (by seeing what pattern of positivity is present). Here’s a short summary of different patterns:

• Homogeneous (diffuse) pattern (the whole nucleus stains green – see the above photo): found with antibodies to chromatin, histones, and (occasionally) double stranded DNA. This pattern is seen in lupus and occasionally in other autoimmune diseases.
• Speckled pattern (random speckles all over the nucleus): found with antibodies to non-DNA nuclear antigens (like ribonucleoprotein). This is the most common immunofluorescent pattern overall – and the least specific for any particular autoimmune disease.
• Nucleolar pattern (a few spots of green within the nucleus): found with antibodies to RNA. Found most frequently in patients with systemic sclerosis (a different autoimmune disease)
• Rim or peripheral pattern (green around the periphery of the nucleus): found with antibodies to double-stranded DNA. This pattern is seen frequently in lupus.

What if the FANA is positive?
Most patients with lupus have positive FANA results. So if the FANA is positive, and the patient has symptoms of lupus, then the patient probably has lupus. If the FANA is positive, but the patient does not have symptoms, then it may not be lupus (and you’d just watch closely for signs/symptoms of lupus developing later). FANAs can be positive in people with no autoimmune disease – and the rate of false positivity increases with age. So to make a diagnosis of lupus, you have to use clinical symptoms and the patient’s history along with the FANA results.

Next time we’ll talk about how these antibodies cause problems in lupus.

Q. While doing some reproductive medicine practice questions in a boards question bank I came across one I couldn’t reason through and was hoping you could help:

A 32 year-old schoolteacher in her first trimester of pregnancy is concered about a student in her class who develops a bright red rash on her cheeks. Two days later, the student’s shoulders, upper thorax, and arms become red, and develop a lacy, reticulated appearance. The physician should monitor this pregnancy closely for the development of which of the fetal conditions?

A.      Congenital heart disease
B.      Cutaneous scarring
C.      Hemolytic anemia
D.      Hydrocephalus
E.      Non-immune hydrops

E. Non-immune hydrops, was the correct answer. I selected C., hemolytic anemia. I was able to pick up on the likely parvovirus B-19 infection of the student and knew that it could cause an aplastic crisis. I think the main problem is that I can’t distinguish the difference between a hemolytic anemia and an aplastic crisis or what non-immune hydrops is.

A. You were correct in your identification of parvovirus B19 (the slapped-cheek disease) as the causative agent in this question. It’s a virus you worry about both in pregnancy and in patients with chronic hemolytic anemias, because parvovirus arrests red cell maturation at the late pronormoblast stage. It also affects platelets, but the main sequelae have to do with red cells.

I just realized that it’s been four years (and one day) since I started this blog! I feel so lucky to be able to connect with so many smart people from so many different countries on our website and through our email lists (check them out over on the left). I hope it’s also fun (and even more important, educational) for you too.

Pathology Student has grown a lot in four years. Here’s some numbers (because it’s fun to measure things):

• We’ve gone from 0 visitors to about 2,500 unique visits per day.
• As of 1:15 today, we’ve had a total of 1,793,358 page loads (59,691 in 2009, 212,297 in 2010, 417,716 in 2011, 777,938 in 2012, and  325,724 so far this year)
• We have 280 posts on everything from general path to specialized hemepath stuff.
• We have 6 books (including a nice free one) that are used a lot by students
• Our two email lists (Path Bites and our Blog Post email) have well over 5,000 subscribers
• We have 6,504 likes on Facebook, and 4,351 followers on Twitter

I’m sure there are some other numbers that I could list, but I’m getting bored with numbers. What really makes me happy is to get emails from readers saying that they get a lot of use out of the website and/or books, or that there is some pathology question they would like help with. Just one nice comment makes my day – and students studying pathology seem to be way up there on the nice scale. So thanks to everyone who has written in with comments or suggestions!

I’ve got some fun stuff planned for this year, including:

• a cool t-shirt
• two more books
• some wild ideas that I will reveal in due time. 

I thought I’d share a list of the posts that have been the most popular over the years. Thanks for visiting!

1. Nephrotic vs. nephritic syndrome

2. Conjugated vs. unconjugated bilirubinemia

3. A quick summary of the 6 types of necrosis

4. Identifying normal leukocytes

5. 10 things to be sure you look at when you read a blood smear

6. What is an M spike?

7. A monoclonal immunoglobulin is present – now what?

8. How to study for boards, part I, part II and part III

9. How can you differentiate between iron-deficiency anemia and thalassemia?

10. Iron-deficiency anemia vs. anemia of chronic disease

11. The Little Orphan Annie tumor

12. Owl’s eye nuclei

13. Teardrop red cells

14. Coagulation quiz

15. A beginner’s guide to the endocrine system

16. What’s the difference between ischemic and hemorrhagic brain infarcts?

17. How to differentiate between acute and chronic inflammation in sections

18. The four main types of rosettes in pathology

19. Does “differentiated” mean it looks different?

20. What’s the difference between pemphigus vulgaris and bullous pemphigoid?

Q. I have myeloma and have relapsed after a stem cell transplant.

I think I understand the disease fairly well, but I don’t get how the M spike relates to IgG, IgM, etc. and also kappa and lambda. Also – what are heavy chains and free light chains, and what does it mean if they are polyclonal or monoclonal?

A. I’m so sorry to hear about your relapse. I’ll try to shed some light on the areas you mentioned; hopefully we can clear those things up for you.

As you probably already know, in multiple myeloma, the main problem is that there are malignant plasma cells in the bone marrow. All the symptoms and complications in myeloma arise from the presence of these cells.

Normal plasma cells are a special kind of lymphocyte that makes antibodies (also called immunoglobulins or Ig, for short). Immunoglobulins have a structure that looks like a Y that has two chains: a shorter (“light”) one and a longer (“heavy”) one. You can see a bunch of Y-shaped antibodies in the image above; one of them is binding to a cell. There are five different kinds of heavy chains (gamma, mu, epsilon, delta, alpha) and two different kinds of light chains (kappa and lambda). The heavy chains are abbreviated G, M, E, D, and A. To make an immunoglobulin molecule, you pick one heavy chaina and one light chain – so there a bunch of different combinations: IgG kappa, IgG lambda, IgM kappa, etc.

Normal immunoglobulins are all slightly different. First, you have all the different types (IgG kappa, etc.). Then, even within those types, there is a huge amount of variability, because of the huge amount of bad stuff, like viruses, that we encounter in the environment. We need to have antibodies against all these different things!

In myeloma, the plasma cells are what we call monoclonal. That means they all descended from an initial cell, which divided into two, and then those two divided into four, and so on. So all the cells in this malignant population of plasma cells are exactly the same (monoclonal), and they all make the exact same kind of immunoglobulin (IgG kappa, say), which we can measure in the blood. Normal plasma cells, in contrast, are called polyclonal, because they are all different from each other.

You can use the words monoclonal and polyclonal to describe immunoglobulins too. Monoclonal immunoglobulins are all exactly the same and are made by a population of monoclonal plasma cells. Polyclonal immunoglobulins are all slightly different from each other, and are made by normal, polyclonal plasma cells.

It’s this big group of monoclonal immunoglobulins, made by the monoclonal, malignant plasma cells, that we refer to as the M-spike (some sources say the M stands for monoclonal). An M spike can be IgG kappa, or IgA lambda, or any possible combination of heavy and light chains. Sometimes, the malignant plasma cells make just heavy chains or just light chains (these are called “free light chains”). The cells are malignant, so they can do whatever they want – they don’t have to make correctly-formed immunoglobulins if they don’t feel like it. So sometimes the M spike will consist of just gamma chains, or just kappa chains, for example.

As part of your initial workup, the lab will find out what type of M-spike you have – and then this M-spike will be followed throughout the course of your disease. When it goes down, it’s assumed that there are less malignant plasma cells around. When it goes up, that means there are more malignant plasma cells. Myeloma treatment has improved drastically in the last several years – and I hope your M spike goes way down! In fact, I hope you never see it again.

• Case 1: 20-year-old male who died suddenly
• Case 2: 72-year-old male with right calf mass
• Case 3: 67-year-old female with pancytopenia
• Case 4: 59-year-old male with severe headaches
• Case 5: 38-year-old female with deep venous thrombi
• Case 6: 13-year-old male with cerebellar mass
• Case 7: 45-year-old male with pulmonary emphysema
• Case 8: 38-year-old male with AIDS and headaches

Back to this case. Take a look at the photo and the question, then scroll down for the answer.

A 25-year-old male presents with a mass on the volar aspect of his forearm. He first noticed the lesion 2 weeks ago, when he developed pain in his arm, and since then it has grown rapidly to reach its current size of approximately 5 cm. A biopsy is shown here. What is the diagnosis?

A. Lipoma
B. Nodular fasciitis
C. Neurofibroma
D. Myxoid liposarcoma
E. Osteosarcoma

(Scroll down for the answer)

The diagnosis in this case is nodular fasciitis. Nodular fasciitis is a benign disorder which most commonly occurs in adults, and most commonly is found on the volar aspect of the forearm. It’s thought to be an over-reaction to trauma (though if you ask patients, many will not remember any preceding trauma).

This lesion is the bane of budding pathologists everywhere. It looks horrible! You’d swear it was some sort of myxoid sarcoma thing – but it’s totally benign. It is composed of plump spindle-shaped fibroblasts with conspicuous nuclei arranged in a myxoid background, usually with some small, thin-walled blood vessels, extravasated red cells, and scattered lymphocytes. Which in and of itself is scary-looking. But in addition, it’s hypercellular, and it has increased mitotic activity – two things you see often in sarcoma.

One point I’d like to make about mitoses: just seeing mitoses is not, in and of itself, diagnostic of malignancy. Lots of benign tumors have an increased mitotic rate. Malignant tumors tend to have more mitoses than benign tumors – but this doesn’t always hold true. Even normal tissues have mitotic figures. So while sometimes helpful in the diagnosis of tumors, in reality, the presence of mitoses just means that the thing, whatever it is, is making new cells.

If you see an atypical mitosis, however, then you worry. One of the most significant and characteristic forms of atypical mitosis is the tri-polar (or pentapolar, or septapolar, though those are less common) mitosis. Normal mitoses do not have an odd number of poles! If you see one of those babies, it’s a malignancy until proven otherwise (and it probably won’t be).

Back to the lesion. The prognosis is excellent for patients with this diagnosis. Excision is curative, and the thing does not come back.