Clinicopathological characteristics of glomeruloid architecture in prostate cancer

Glomeruloid architecture is the least common Gleason 4 growth pattern in prostate adenocarcinoma. Its clinicopathological features and relation with cribriform architecture, which has been recognized as an adverse feature, remains to be established. Our objective was to investigate clinicopathological features of glomeruloid architecture in radical prostatectomies. We reviewed 1064 radical prostatectomy specimens and recorded Grade Group, pT-stage, margin status, Gleason pattern percentages, and growth patterns. Simple and complex glomerulations were distinguished by gland size and intraluminal cribriform protrusions. Clinical endpoint was biochemical recurrence-free survival. Glomerulations were identified in 365 (34%) specimens. In 472 Grade Group 2 patients, 210 (44%) had simple and 92 (19%) complex glomerulations. Complex glomerulations coincided with cribriform architecture more often than simple glomerulations (67% versus 52%; P = 0.01). Men with simple glomerulations had significantly lower prostate specific antigen (PSA) levels (9.7 versus 12.1 ng/ml; P = 0.03), percentage Gleason pattern 4 (19% versus 25%; P = 0.001), extra-prostatic extension (34% versus 50%; P = 0.01), and positive surgical margins (25% versus 39%; P = 0.04) than those with cribriform architecture. Extra-prostatic extension (37%) and positive surgical margins (30%) in men with complex glomerulations resembled those with simple glomeruloid rather than those with cribriform architecture. In multivariate Cox regression analysis adjusted for PSA, pT-stage, margin status, and lymph node metastases, cribriform architecture had independent predictive value for biochemical recurrence-free survival (hazard ratio (HR)) 1.9; 95% confidence interval (CI) 1.2–2.9; P = 0.004), while simple (HR 0.8; 95% CI 0.5–1.2; P = 0.26) and complex (HR 0.9; 95% CI 0.5–1.6; P = 0.67) glomerulations did not. Both simple and complex glomeruloid architecture are associated with better outcome than cribriform architecture in Grade Group 2 prostate cancer patients. Therefore, glomeruloid pattern and particularly complex glomerulations should not be classified as a cribriform growth pattern variant in radical prostatectomy specimens.