When Interpreting Skin Biopsies, Pathologists Often Disagree

MedicalResearch.com Interview with:

Joann G. Elmore M.D., M.P.H. Professor of Medicine,  Adjunct Professor of Epidemiology, University of Washington School of Medicine Harborview Medical Center Seattle, WA 98104-2499

Dr. Elmore

Joann G. Elmore M.D., M.P.H.
Professor of Medicine,
Adjunct Professor of Epidemiology,
University of Washington School of Medicine
Harborview Medical Center
Seattle, WA 98104-2499

MedicalResearch.com: What is the background for this study?

JE: Previous studies on diagnostic accuracy in interpreting melanocytic lesions exist but have small sample size, inclusion of experts only, or small numbers of specimens. We sought to examine accuracy and reproducibility in melanocytic skin lesions by improving upon the methodological limitations of previous studies. Specifically, we recruited a large national sample of practicing community and academic pathologists with a wide range of experience, and we utilized a large sample of biopsy cases that were carefully selected. Given that diagnostic errors can lead to patient deaths and invasive melanoma kills more than 9,000 Americans each year, we wanted to study the issue of diagnostic accuracy in interpreting melanocytic skin lesions in a very robust fashion.

MedicalResearch.com: What are the main findings?

JE: The main finding of our study is that pathologists agreed with the consensus reference panel for the majority of skin biopsies that were benign or high stage invasive melanoma. However, for intermediate lesions in the large gray zone, agreement with the consensus reference panel was less than 50%. When pathologists interpreted these cases on two separate occasions separated by many months, they also disagreed with their initial diagnosis on these intermediate cases about 40% of the time.

MedicalResearch.com: What should readers take away from your report?

JE: It is important to mention that our results do not point the finger at pathologists. Rather, our findings reflect the difficulty of the gray zone of intermediate lesions, and highlight that our diagnostic processes are limited by our current technology in addition to the insufficient criteria currently in use for distinguishing these intermediate lesions. Future advances in diagnostic technology and molecular sciences may improve accuracy, but in the meantime uncertainty in medicine needs to be acknowledged.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

JE: Future studies should focus on developing better diagnostic tools to support pathologists and examine the utility of a standardized classification system. We are currently in the process of further studying our own MPATH-Dx© classification system, in hopes that it, or some other standardized classification system, will be adopted into clinical practice. This might improve communication amongst pathologists, treating physicians, and patients.

MedicalResearch.com: Is there anything else you would like to add?

JE: As I mention in my associated opinion piece in The BMJ (1), I greatly appreciate the time and commitment pathologists put into their clinical work, and they do so with the utmost skill and thoughtful commitment. These skin biopsies are challenging to interpret. We are very grateful to the pathologists who participated in our study, as they invested an incredible amount of their personal time to help move the field forward.

MedicalResearch.com: Any disclosures?

JE: As noted in the acknowledgements in The BMJ, this work was supported by the National Cancer Institute, NIH.


Joann Elmore: When diagnostic uncertainty hits home


The BMJ   June 28, 2017 article on pathologists’ diagnosis of invasive melanoma and melanocytic lesions: accuracy and reproducibility.

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Last Updated on July 3, 2017 by Marie Benz MD FAAD