Significance of Paneth-cell-like differentiation in prostatic adenocarcinoma: A retrospective cohort study of 80 cases.

The grading and prognosis of prostatic adenocarcinoma with Paneth cell-like differentiation (PanEC) of the prostate is controversial with limited available data. We identified 80 cases, not previously published, of PanEC first identified on biopsy (n=69), transurethral resection (TURP)(n=1) and radical prostatectomy (RP) (n=10). Out of 69 biopsies, 22 did not have a grade assigned. In the remaining 47 biopsies, the Grade Groups (GG) of the associated usual prostatic adenocarcinoma were GG1-2 (n=34) and GG 3-5 (n=13). Of 10 radical prostatectomies (RP), the GG were GG1-2 (n=8), GG4 (n=1), treatment effect (n=1), pathological stages were pT2 (n=8), and pT3a (n=2), all with negative lymph nodes. We analyzed 19 cases with available follow-up only associated with GG1-2 conventional cancer; 9 underwent RP, GG at RP: GG1-2 (n=7); treatment effect (n=1), missing data (n=1); pathologic stages were pT2 (n=6) and pT3a (n=3); no positive regional lymph nodes; 3 were managed with active surveillance, without follow-up progression; 5 patients underwent radiation +/- hormone therapy, none showed follow-up progression; 2 (10.5%) patients were recommended to undergo radiotherapy with no further follow-up. Out of the cases with available follow-up, 9 were not associated with conventional adenocarcinoma; the majority of these cases were treated with radiation therapy or active surveillance without evidence of progression. In summary, although a minority of PanEC are associated with conventional higher grade adenocarcinoma and have progression after treatment, the majority have favorable findings justifying the consideration of them as more indolent tumors despite cases where the PanEC resembles Gleason pattern 5 adenocarcinoma.

Human pathology. 2020 May 20 [Epub ahead of print]

Daniela C Salles, Douglas A Mata, Jonathan I Epstein

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: ., Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY., Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland; Departments of Urology and Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: .