Dr. Ahsanuddin Online: Lecture Supplementary Materials - FYI Only
Dr. Ahsanuddin Online: Lecture Supplementary Materials - FYI Only
I expect you to recognize basic tissue types and neoplasms, based on clinical and pathologic data. Images may be a part of that information, but will not be the only clues provided (unless there is a defining pathologic feature that gives you the diagnosis immediately - that I would expect you to know). Remember: my primary goal is not to have you to regurgitate simple facts back to me on the exam. Rather, I want you to be able to synthesize, analyze, and USE the information I have given you.
Again, my job is to teach you to think clinically. I will ask straightforward questions, designed to test whether you know (very) basic morphology and elements that go into a pathologic diagnosis, as well as being able to reason through a differential diagnosis to reach a final answer, taking into account clinical presentation, physical exam, labs, and any secondary screening tests, as necessary.
As for suggested study topics, I want you to know how to differentiate between clinical disease states; the difference between benign and malignant neoplasms (as well as borderline tumors, if relevant) IN GENERAL; and the clinicopathologic differences between tumor categories that are specific enough to narrow your differential.
Don’t overthink it. I will ask no trick questions. You’re second-years, not pathology residents, and I am fully cognizant of that fact. All I want, is for you to be able to ask the right questions to get to a diagnosis, and understand what that diagnosis means in terms of clinical importance, prognosis, epidemiology, etc.
Normally, when people ask me what areas of a topic they should study, I get frustrated: you can’t be an effective physician if you only know the part of medical knowledge that’s in BOLD PRINT.
HOWEVER, since hematopoietic neoplasms (especially lymphomas) are fairly unique in that they often look exactly the same, morphology is often of limited value, and these entities have to be differentiated by immunophenotype and molecular studies.
Therefore, I would suggest you focus your attention on the information I have given you in the following hierarchy of importance (for each entity):
You do not have to memorize all the pictures. They are there for reference. I expect you to recognize basic tissue types and neoplasms, based on clinical and pathologic data. Images may be a part of that information, but will not be the only clues provided (unless there is a defining pathologic feature that gives you the diagnosis immediately - that I would expect you to know). Remember: my primary goal is not to have you to regurgitate simple facts back to me on the exam. Rather, I want you to be able to synthesize, analyze, and USE the information I have given you.
Again, my job is to teach you to think clinically. I will ask straightforward questions, designed to test whether you know (very) basic morphology and elements that go into a pathologic diagnosis, as well as being able to reason through a differential diagnosis to reach a final answer, taking into account clinical presentation, physical exam, labs, and any secondary screening tests, as necessary.
As for suggested study topics, I want you to know how to differentiate between clinical disease states; the difference between benign and malignant neoplasms (as well as borderline tumors, if relevant) IN GENERAL; and the clinicopathologic differences between tumor categories that are specific enough to narrow your differential.
Don’t overthink it. I will ask no trick questions. You’re second-years, not pathology residents, and I am fully cognizant of that fact. All I want, is for you to be able to ask the right questions to get to a diagnosis, and understand what that diagnosis means in terms of clinical importance, prognosis, epidemiology, etc.
I have noticed some trends in the questions I've received on these lectures over the years, so I have some general suggestions:
I don’t expect you to be pathologists. I only want you to recognize the basic uses of the various stains I touched on in class, as well as morphologic findings which are SPECIFICALLY linked to a particular organism or condition. If it's not uniquely associated with a particular organism or disease entity, then I don't consider it particularly important at this stage in your training.
In general, on exams I will try to give you multiple clues in a patient scenario, whether clinical, laboratory, or morphologic, so that you can come to the right answer in multiple ways. The importance is to narrow your differential to get a diagnosis, and then know enough about that diagnosis to be able to answer the question. I mostly want you to learn how to think through a problem to reach a conclusion, and less so necessarily to just memorize images.
You need to be able to recognize (histologically) the difference between follicular (FL), diffuse (DLBCL, LBL, ALCL, extranodal NK/T), and starry sky architectural patterns (Burkitt, but also may be seen in LBL and DLBCL), and know the lymphomas associated with them.
You need to be able to recognize (cytologically) neoplasms with distinctive cell morphology: classic Hodgkin lymphoma, anaplastic large cell lymphoma (ALCL), adult T cell leukemia/lymphoma (ATLL), acute promyelocytic leukemia (APL), AML with inv16, etc.
You need to know the distinctive cytogenetic abnormalities that underly various neoplasms (e.g. CML has a 9;22 translocation), as well as specific molecular lesions that define hematopoietic disease entities (eg. t(9;22) in CML = BCR-ABL1 fusion).
Lastly, you need to know the phenotypic markers that distinguish specific neoplasms from each other, and the context in which they are diagnostically important: eg. naive B cell tumors (CLL and MCL) are both positive for CD20 and CD5. However, MCL is also positive for BCL1, while CLL is not (CLL is also positive for LEF1, unlike MCL).
In the broadest sense, B lineage cells have three stages of development: (blast, mature lymphocyte, and plasma cell), and the mature B lymphocyte subset has three major steps in maturation (Pre-GC, GC, and Post-GC). T cells can be said to have two stages of development (blasts to lymphocyte), and mature T lymphocytes go through three (main) stages of development: CD4/CD8 double negative, CD4/CD8 double positive, and then single positive (CD4 or CD8).
A LOT of people have expressed confusion about CD markers and which ones I expect you to know. I realize it can be overwhelming, but it’s the best way to tell these tumors apart (and this is how we do it in clinical practice). More information on each marker is included in the Appendices, for reference. This additional material is for your information (FYI) only. You will not be tested on the Appendix material.
What I want you to understand from all this, is that markers are clustered by lineage, stage of development, stage of maturation, etc. In this way, you can tell one lymphocyte from another, even if they look the same under the microscope. By analogy, you can tell the lymphomas apart by the phenotype of the cells from which they are derived (the 'Ontogeny' model).
These are the markers I want you to know. I would suggest you break down the different markers for each disease by the unique features of their corresponding normal counterpart:
Normal:
B cell lymphomas
Oddballs: B cell lymphomas without a well-defined normal counterpart
T cell lymphomas
Non-lymphoid hematopoietic malignancies:
On a philosophical note, memorization may be required to master the Science of medicine, and you have your entire careers to learn it. There's a lot to learn, and you'll need it for board exams like the COMLEX, but that won't make you doctors.
Analysis is the Art of medicine, and that the most important preparation for clinical practice next year, when you hit your clerkships. Learn to think through a problem, from the clinical context, history, and physical evidence, to get to a differential diagnosis. Then determine what more information you need to get to a final diagnosis, and how to acquire it. Once you identify a diagnosis, that will inform your treatment decisions, which is the ultimate goal of everything you have done up to this point.
I do want you to learn the science, because that's the basis for the knowledge you will gain throughout the rest of your professional lives.
But if I can help you learn how to think, then I have achieved my highest goals. Good Luck.
Respectfully,
Dr. Ahsanuddin
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