Histological parameters and stromal desmoplastic status affecting accurate diagnosis of extraprostatic extension of prostate cancer using multi‐parametric magnetic resonance imaging

Objective To investigate the clinicopathological factors affecting discrepancies between multi‐parametric magnetic resonance imaging (mpMRI) and histopathological evaluation for diagnosis of extraprostatic extension (EPE) of prostate cancer. Methods One hundred‐and‐three lesions from 96 cases with suspected EPE on preoperative mpMRI, of which 60 and 43 showed bulging and frank capsular breach, respectively, were grouped according to pathological (p)EPE in radical prostatectomy specimens. Additionally, clinicopathological/immunohistochemical findings for periostin reflecting a desmoplastic stromal reaction were compared between these groups. Results pEPE was detected in 49 (48%) of the 103 lesions. Of these, 25 (42%) showed bulging and 24 (56%) showed frank capsular breach on MRI. In the total cohort, the absence of pEPE was significantly associated with a lower Gleason Grade Group (GG) (p