Should Pathologists Diagnose ‘‘Adenocarcinoma’’When They Encounter a Single Small Atypical
Focus in a Prostate Biopsy?
In Response:
Both Letters to the Editor referring to our paper ‘‘Variability in diagnostic opinion among pathologists for
single small atypical foci in prostate biopsies’’ challenge its recommendation to obtain second opinion of a specialist pathologist before making a diagnosis of adenocarcinoma on a focus, comprising
5 or less atypical acini.4 Dr Dalton1 argues that the clinical outcome of men with these lesions, irrespective
of the diagnosis, is any how favorable.His view seems to be further corroborated by another paper recently published in this Journal5 on false negative prostate biopsies that is, biopsies where the diagnosis of prostate cancer was missed. The missed lesions were small foci of Gleason score 6 (3 +3) denocarcinomas in a single biopsy. Indeed,none of the men with a false-negative biopsy seemed to have a cancer advanced beyond the curable stage at the time of prostate cancer diagnosis 4 to 8 years later and the cancers did not differ from those found in men with a previous truly negative biopsy result.
To our opinion, the argument raised by Dr Dalton1 might be valid at a population level, but may not apply
for the individual man, in whom the small atypical focus could represent the tip of the iceberg, requiring
additional clinical investigations. As literature has shown that intercollegial consultation leads to more definite diagnoses of benign or cancer in prostate biopsies,3 we maintain our recommendation on this matter.The reason for the disagreement of Drs Gilks and Huntsmans2 with our position is the lack of consensus among the experts themselves. On account of this lack of agreement on the diagnosis
of such small foci, no individual expert can function as a ‘‘golden standard’’and therefore, they propose that pathologists should refrain from making a definite diagnosis of cancer when the number of atypical acini does not exceed a given number, for example, 10 acini. In contrast, we would argue that not all lesions with fewer than 6 atypical acini in our study suffered from a lack of consensus among experts, and in average the experts did better than the general pathologists of our study. The proportion
of consensus in these cases might in fact be higher in a real-life situation as compared with this virtual microscopy environment, for reasons outlined in the discussion of our paper. Thus, we do not agree with
a recommendation that would deny a pathologist’s right to render a definite diagnosis of adenocarcinoma when he would feel comfortable enough to do so. Obviously, we endorse the view
that the scientific community should continue to look for additional tools to reduce the diagnostic uncertainty on these small atypical foci. In the mean time, we would encourage pathologists
to seek advice from specialist pathologists to reduce the uncertainty of their diagnosis under these circumstances.

Theodorus H. Van der Kwast, MD,
PhD*
Jonathan I. Epstein, MD, PhDw
*Department of Pathology University
Health Network Toronto, Canada
wDepartment of Pathology
The Johns Hopkins Medical Institutions
Baltimore, MD