Criteria: The Currency of Fundamentals by Mark A. Hurt, MD
Entry posted by Mark A. Hurt MD
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Criterion ("criterion." Webster's Third New International Dictionary, Unabridged. Merriam-Webster, 2002. [url="http://unabridged.merriam-webster.com"]http://unabridged.merriam-webster.com[/url] (23 Apr. 2012)
1) a characterizing mark or trait
2) a standard on which a decision or judgment may be based
3) an expression by whose value varieties of a mathematical form may be distinguished
Etymology: Greek kritrion, from krits judge, from krinein to separate, decide -- more at CERTAIN
The first two definitions are applicable to dermatopathologists, but the etymology gets at the heart of the matter. It is what we do every day, perhaps a few dozen to a few score to even a few hundred times a day. It is what we look for to establish a diagnosis.
So, how do we know what to look for? How do we establish a valid criterion that leads to a diagnosis? If you introspect, you will find that when your were beginning as a resident in pathology or dermatology, you were inundated with reading material -- in addition to case work. As one who trained in pathology before becoming a dermatopathologist, I was inundated with reading and with cases from patients, the diagnosis of most I had no real clue. My teachers indicated that such and such was the diagnosis, but even they did not often know why it was the diagnosis.
Why, indeed!
Given that concepts of disease stem from separating a host of concrete, mostly perceptual data, in the case of dermatopathology, it is the actual separation of the data into their differences and similarities that occurs before the judgment, conceptually, of the data. The judgment is the diagnosis -- the end result.
But what of the separation? The separation of what?
The deeper meaning of a criterion is that it is the result of observing things in nature and separating them out into groups of a similar kind based on their differences and similarities. This is the most basic kind of observation that one makes in the beginning of his career in observing the changes in tissues under a microscope. Because it is so fundamental, the observations must be defined uniformly so as to be the "currency" of communication before one is able to reach the goal of making a diagnosis. This "currency" of language, however, is not often uniform. Because of the lack of uniformity of definition in the fields of pathology and dermatopathology, controversies develop, and, as a consequence, whole schools, that advocate a particular point of view, emerge.
Let's consider just one example. In the study of melanocytic proliferations, there is the school that advocates the terms "atypia" and "dysplasia" for a wide variety of cellular and structural findings. There is another school, a minor one, that rejects both concepts as invalid; this school advocates that classes of lesions need sharp definition based on criteria, and that the terms "atypia" and "dysplasia" preclude sharp definition of any criteria.
I am of the latter school. I argue that when one looks through a microscope, one identifies specific, concrete things. One sees cells and stroma in a variety of patterns; one identifies cells that are monomorphic or pleomorphic. The nuclei have a specific quality; the cytoplasm has a variety of colors and quantity. The terms "dysplasia" and "atypia" don't come close to stating these changes; those terms were not meant to come close. Those terms are highly abstract; therefore, they are used in a variety of ways, often with disparate meanings. In short, "dysplasia" and "atypia" are closer to diagnostic terms than terms of direct perception, yet they diagnose nothing, and they were never meant to do so. In fact, the real meaning of those terms is to express one's uncertainty about a finding.
How, then, should one use concrete findings toward developing a diagnosis? The answer is surprisingly simple, but the implementation is difficult. A diagnosis is the sum, and simplest statement, of its criteria. The implementation, however, requires identification of the fundamental elements that constitute each criterion, identification of the criteria that are relevant in a given case, and weighing whether sufficient criteria have been identified that establish a definitive diagnosis in a given case.
I can say that in the realm of melanocytic lesions, as well as all neoplasms, there are only 4 possible diagnoses: malignant, benign, malignant in conjunction with benign, and I don't know. It might be surprising to learn that, perhaps, only 3 to 4 criteria are required to establish a diagnosis in most cases. "Atypia" and "dysplasia" won't help you.
For further reading, you might be interested in a recent article by Mello-Thoms et al., who analyzed residents attempting to make diagnoses of inflammatory skin diseases. Their results are interesting, but I think it might be more interesting to analyze the results of dermatopathologists 1 year out of training vs. 10 years out vs. 20 years out. I think it might be more interesting because this spectrum of dermatopathologists would have had real world experience in rendering a diagnosis on which someone's life depends, rather than in a residency, where the wrong diagnosis will be overridden, as a rule, by an attending. The pressure of rendering a diagnosis, and taking responsibility for it, has a profound effect.
Reference:
Mello-Thoms C, Mello CAB, Medvedeva O, Castine M, Legowski E, Gardner G, Tseytlin E, Crowley R. Perceptual Analysis of the Reading of Dermatopathology Virtual Slides by Pathology Residents. Arch Pathol Lab Med 2012; 136:551-562.
[url="http://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2010-0697-OA"]http://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2010-0697-OA[/url]
1) a characterizing mark or trait
2) a standard on which a decision or judgment may be based
3) an expression by whose value varieties of a mathematical form may be distinguished
Etymology: Greek kritrion, from krits judge, from krinein to separate, decide -- more at CERTAIN
The first two definitions are applicable to dermatopathologists, but the etymology gets at the heart of the matter. It is what we do every day, perhaps a few dozen to a few score to even a few hundred times a day. It is what we look for to establish a diagnosis.
So, how do we know what to look for? How do we establish a valid criterion that leads to a diagnosis? If you introspect, you will find that when your were beginning as a resident in pathology or dermatology, you were inundated with reading material -- in addition to case work. As one who trained in pathology before becoming a dermatopathologist, I was inundated with reading and with cases from patients, the diagnosis of most I had no real clue. My teachers indicated that such and such was the diagnosis, but even they did not often know why it was the diagnosis.
Why, indeed!
Given that concepts of disease stem from separating a host of concrete, mostly perceptual data, in the case of dermatopathology, it is the actual separation of the data into their differences and similarities that occurs before the judgment, conceptually, of the data. The judgment is the diagnosis -- the end result.
But what of the separation? The separation of what?
The deeper meaning of a criterion is that it is the result of observing things in nature and separating them out into groups of a similar kind based on their differences and similarities. This is the most basic kind of observation that one makes in the beginning of his career in observing the changes in tissues under a microscope. Because it is so fundamental, the observations must be defined uniformly so as to be the "currency" of communication before one is able to reach the goal of making a diagnosis. This "currency" of language, however, is not often uniform. Because of the lack of uniformity of definition in the fields of pathology and dermatopathology, controversies develop, and, as a consequence, whole schools, that advocate a particular point of view, emerge.
Let's consider just one example. In the study of melanocytic proliferations, there is the school that advocates the terms "atypia" and "dysplasia" for a wide variety of cellular and structural findings. There is another school, a minor one, that rejects both concepts as invalid; this school advocates that classes of lesions need sharp definition based on criteria, and that the terms "atypia" and "dysplasia" preclude sharp definition of any criteria.
I am of the latter school. I argue that when one looks through a microscope, one identifies specific, concrete things. One sees cells and stroma in a variety of patterns; one identifies cells that are monomorphic or pleomorphic. The nuclei have a specific quality; the cytoplasm has a variety of colors and quantity. The terms "dysplasia" and "atypia" don't come close to stating these changes; those terms were not meant to come close. Those terms are highly abstract; therefore, they are used in a variety of ways, often with disparate meanings. In short, "dysplasia" and "atypia" are closer to diagnostic terms than terms of direct perception, yet they diagnose nothing, and they were never meant to do so. In fact, the real meaning of those terms is to express one's uncertainty about a finding.
How, then, should one use concrete findings toward developing a diagnosis? The answer is surprisingly simple, but the implementation is difficult. A diagnosis is the sum, and simplest statement, of its criteria. The implementation, however, requires identification of the fundamental elements that constitute each criterion, identification of the criteria that are relevant in a given case, and weighing whether sufficient criteria have been identified that establish a definitive diagnosis in a given case.
I can say that in the realm of melanocytic lesions, as well as all neoplasms, there are only 4 possible diagnoses: malignant, benign, malignant in conjunction with benign, and I don't know. It might be surprising to learn that, perhaps, only 3 to 4 criteria are required to establish a diagnosis in most cases. "Atypia" and "dysplasia" won't help you.
For further reading, you might be interested in a recent article by Mello-Thoms et al., who analyzed residents attempting to make diagnoses of inflammatory skin diseases. Their results are interesting, but I think it might be more interesting to analyze the results of dermatopathologists 1 year out of training vs. 10 years out vs. 20 years out. I think it might be more interesting because this spectrum of dermatopathologists would have had real world experience in rendering a diagnosis on which someone's life depends, rather than in a residency, where the wrong diagnosis will be overridden, as a rule, by an attending. The pressure of rendering a diagnosis, and taking responsibility for it, has a profound effect.
Reference:
Mello-Thoms C, Mello CAB, Medvedeva O, Castine M, Legowski E, Gardner G, Tseytlin E, Crowley R. Perceptual Analysis of the Reading of Dermatopathology Virtual Slides by Pathology Residents. Arch Pathol Lab Med 2012; 136:551-562.
[url="http://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2010-0697-OA"]http://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2010-0697-OA[/url]
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