Whole mount histopathological correlation with prostate MRI in Grade I and II prostatectomy patients

Multiparametric magnetic resonance imaging (mpMRI) is increasingly used in detection and surveillance of prostate cancer. However, the co-localization of lower grade lesions between mpMRI and histopathologic specimen has not been well established.

We aim to determine the factors on final histopathological exam that correlate to tumor visibility for Grade I and II disease on mpMRI.

Fifty-five patients who underwent radical prostatectomy from July 2014 to June 2016 were analyzed for the study. Of the sample of 55 patients, 18 were found to have Gleason score (GS) of 3 + 3 or 3 + 4 disease, and then were re-reviewed and annotated by a pathologist. Lesion diameter, area, and distance from the prostate capsule were measured. The annotated lesions were co-localized to the MRI report.

Of the 184 lesions identified on the whole mount histopathologic slides, 106 (57.6%), 62 (33.7%), 14 (7.6%), and 2 (1.1%) of the lesions had a GS of 3 + 3, 3 + 4, 4 + 3, and 4 + 4, respectively. On analysis, 27.3% (24/88) of GS 6 (< 1.5 cm in size), and 88.9% (16/18) of GS 6 (> 1.5 cm in size) were identified (p < 0.001). Additionally, when assessing lesion proximity to the prostatic capsule, 46.1% (41/89) of lesions closer (≤ 0.05 cm), and 30.5% (29/95) of lesions further (> 0.05 cm) from the capsule were visualized.

Lesion diameter, area, and capsule proximity correlated with MRI visibility. Further studies are encouraged to validate the findings of our study.