Foamy gland adenocarcinoma of the prostate: incidence, Gleason grade, and early clinical outcome

Foamy gland carcinoma is a variant of prostatic acinar adenocarcinoma characterized by abundant foamy cytoplasm and often pyknotic nuclei. Limited data exist regarding outcome and the clinicopathologic attributes of this variant. We screened 477 radical prostatectomies for foamy gland carcinoma to determine the incidence, amount, and Gleason grade/score of foamy gland carcinoma within the prostate. Time until prostate-specific antigen biochemical recurrence after radical prostatectomy was compared for both foamy and control/nonfoamy cases. For validation of incidence, Gleason grade, and pathologic stage, a second series of 100 consecutive radical prostatectomies was screened for foamy gland carcinoma. Foamy gland carcinoma was found in 69 (14.5%) of 477 cases. The median Gleason score of the foamy component was 7, which was not significantly different from the Gleason score of the nonfoamy component within those cases or the 408 nonfoamy cases. The most common Gleason score was 7 (44/69). There was no difference between foamy gland and nonfoamy gland cases in recurrence rate (23% versus 22%) or the average time to prostate-specific antigen recurrence (130 versus 151 months). In the second series, foamy gland carcinoma was found in 23% of cases and had a median Gleason score of 7; and the most common Gleason score was 7 (11/23). Foamy gland carcinoma exists in a significant subset of prostatic carcinomas. This variant does not appear to harbor a different prognosis compared with usual acinar adenocarcinoma, but diagnostic recognition of foamy gland carcinoma is important because there is a Gleason grade 4 element in the majority of cases.