Presence of corpora amylacea among prostate cancer cells: an unrecognised feature of intraductal carcinoma of the prostate

Corpora amylacea (CA) is usually present in benign prostatic ducts and acini, and its presence is considered suggestive of negative or low-risk prostate cancer. The clinicopathological definition of CA among prostate cancer cells (CAPCCs)-described as CA entirely surrounded by invasive cancer cells-has not been discussed. As intraductal carcinoma of the prostate (IDC-P) is a well-known adverse prognostic factor in prostate cancer, this study aimed to elucidate the relationship between CAPCC and IDC-P. We enrolled 366 patients who underwent robotic assisted radical prostatectomies between 2012 and 2018 at Aichi Medical University Hospital. All surgical specimens were independently reviewed by two genitourinary pathologists. The median age of the patients was 68.5 years; the median serum prostate-specific antigen was 6.49 ng/mL. IDC-P was observed in 143 (39.1%) patients, while the presence of CAPCC was observed in 47 cases (12.8%). Patients with CAPCC were associated with more advanced clinical and pathological T stages, as well as Gleason scores, than those without CAPCC (p=0.018, p<0.001, p=0.036). Notably, the presence of CAPCC was significantly associated with the presence of IDC-P (39 cases) and a high Gleason score compared with the absence of CAPCC (12 cases) (p<0.001 and p=0.036, respectively). The presence of CAPCC is an adverse pathological feature, often closely related to IDC-P. Therefore, CAPCC may be a surrogate finding to detect IDC-P via haematoxylin and eosin staining.