Case ‒ Foamy high-grade prostatic intraepithelial neoplasia: A false positive for prostate cancer on multiparametric magnetic resonance imaging?

Thenappan Chandrasekar, Hanan Goldberg, Zachary Klaassen, Nathan Perlis, Antonio Finelli, Andrew Evans, Sangeet Ghai


The introduction of multiparametric magnetic resonance imaging (mpMRI) of the prostate, and specifically the introduction of diffusion-weighted imaging (DWI), has significantly impacted the diagnosis of prostate cancer and the management of clinically localized prostate cancer. Indeed, its localizing ability has now opened up opportunities to target focal lesions in partial gland ablation therapy as a treatment option for localized prostate cancer. With negative predictive rates of mpMRI approaching 90% in certain series,1 mpMRI has the ability to discriminate between clinically significant intermediate-to-high-risk prostate cancer and low-risk indolent disease. However, false positives can occur. In recent studies, lesions observed on MRI were classified as tumour on targeted biopsy in 47.6% to over 94% for tumours larger than 0.5 ml in volume.2,3 Herein, we present a case of a rare non-cancer, but putatively pre-malignant prostatic histology that was found on biopsies directed at a category 5 Prostate Imaging Reporting and Data System (PIRADS) v2 lesion.

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