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A pathologist associated with medical education and the explanation of disease mechanisms. The textbook bearing his name distinguishes hypertrophy from hyperplasia, linking changes in tissue size to different underlying cellular processes.^[ref]

Portrait attempt: Royal College of Pathologists Bulletin, January 2022, featured-article photograph caption identifies Professor Sir James Underwood. The pathology textbook title refers to James Underwood.

Joann G. Elmore is a physician whose research examines variability in cancer diagnosis, including how consistently pathologists classify biopsy material. Her research group's description connects that work with statistics and machine learning for evaluating diagnostic decisions.^[ref]

In a 2017 primary study, Elmore and colleagues assembled 240 skin biopsy cases and gave participating pathologists sets of 36 or 48 cases. The design included a second interpretation of the same cases at least eight months later; 187 pathologists completed 8,976 interpretations in the first phase. Comparing an observer with their own later reading, with other observers and with a reference panel answers three different questions about statistical classification.^[ref]

The distinction is within-observer agreement versus reference agreement. In an illustrative set of 20 cases, an observer might repeat 18 of their earlier classifications but agree with a reference classification on only 14: the two proportions are $18/20=90\%$ and $14/20=70\%$. Repeating the same erroneous category increases the first proportion without improving the second. These are invented counts to explain the design, not results from Elmore's study. A consensus reference is an explicitly defined comparison standard; it does not make a panel infallible, and the diagnostic mix of a selected test set must be considered before interpreting an overall agreement percentage.

A pathologist studies and interprets changes in cells, tissues and organs associated with disease. In clinical work, this can involve examination of a biopsy, surgical specimen or body fluid alongside molecular and clinical information. Microscopic organization and molecular test results provide complementary evidence rather than interchangeable measurements. ^[ref]

For example, recognizing an abnormal tissue pattern answers a different question from identifying a particular genetic alteration in the same specimen. Relating both findings to the location and course of disease can refine a diagnosis. The role combines biological mechanism with careful control of specimen identity, sampling and interpretation.

A physician and pathologist who investigated tissue changes and their distribution in disease. His account of amyloid degeneration is an example of connecting microscopic material with alterations across internal organs, while preserving the historical meaning of its terminology.^[ref]

Portrait: Wellcome portrait on Wikimedia Commons.