Variability in Diagnostic Opinion Among Pathologists for Single Small Atypical Foci in Prostate Biopsies

Theodorus Kwast, A Evans, G Lockwood, D Tkachuk, DG Bostwick, JI Epstein, PA Humphrey, R Montironi, Arno van Leenders, CG Pihl, I Neetens, PM Kujala, M Laurila, C Mazerolles, L Bubendorf, A Finelli, K Watson, J Srigley

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Pathologists are increasingly exposed to prostate biopsies with small atypical foci, requiring differentiation between adenocarcinoma, atypical small acinar proliferation Suspicious for malignancy, and a benign diagnosis. We Studied the level of agreement for such atypical foci among experts in urologic pathology and all-round reference pathologists of the European Randomized Screening study of Prostate Cancer (ERSPC). For this purpose, we retrieved 20 prostate biopsies with small (most < 1 mm) atypical foci. Hematoxylin and eosin-stained slides, including 10 immunostained slides were digitalized for virtual microscopy. The lesional area was not marked. Five experts and 7 ERSPC pathologists examined the cases. Multirater K statistics was applied to determine agreement and significant differences between experts and ERSPC pathologists. The K value of experts (0.39; confidence interval, 0.29-0.49) was significantly higher than that of ERSPC pathologists (0.21; confidence interval, 0.14-0.27). Full (100%) agreement was reached by the 5 experts for 7 of 20 biopsies. Experts and ERSPC pathologists rendered diagnoses ranging from benign to adenocarcinoma on the same biopsy in 5 and 9 biopsies, respectively. Most of these lesions comprised between 2 and 5 atypical glands. The experts diagnosed adenocarcinoma (49%) more often than the ERSPC pathologists (32%) (P < 0.001). As agreement was particularly poor for foci comprising < 6 glands, we would encourage pathologists to obtain intercollegial consultation of a specialized pathologist for these lesions before a carcinoma diagnosis, whereas clinicians may consider to perform staging biopsies before engaging on deferred or definite therapy.
Original languageUndefined/Unknown
Pages (from-to)169-177
Number of pages9
JournalAmerican Journal of Surgical Pathology
Issue number2
Publication statusPublished - 2010

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  • EMC MM-03-24-01

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