Micropapillary carcinoma: new variant of prostatic acinar adenocarcinoma

A micropapillary variant of prostatic acinar adenocarcinoma has not been reported in the literature. Herein, we report a case of a 50-year-old patient who presented with an elevated prostate-specific antigen concentration and was subsequently diagnosed with prostatic acinar adenocarcinoma on biopsy. Radical prostatectomy specimen revealed prostatic carcinoma with Gleason score 4 + 5  =  9/10, with micropapillary component constituting 80% of tumor volume. Immunohistochemical studies of the prostate carcinoma showed a homogeneously positive prostate-specific antigen and α-methylacyl-CoA racemase, high-molecular-weight cytokeratin, and p63 protein cocktail pattern of staining in both micropapillary and conventional components. Pelvic lymph nodes were negative for metastatic disease. In contrast to the aggressive behavior of micropapillary carcinomas of other organs, the disease in our patient has thus far followed a more benign course, with low stage on presentation and a 2-year follow-up free of disease. However, prognostic correlation should be established on large series in order to assign this variant to a grade category within the Gleason scheme.