1. Presented by Dr. Epstein and prepared by Dr. J. David Peske.

Clinical History. A 65 year old man with an elevated serum PSA level underwent 12 core biopsy. Two cores had typical Grade Group 3 adenocarcinoma of the prostate. Three other cores had a more poorly differentiated component. At another institution, the following stains were performed on the poorly differentiated component: PSAP " focally positive; NKX3.1 " negative; P501S " negative; PSA " negative. Cystoscopy was normal.
What is the diagnosis of the cores with the poorly differentiated tumor?











Choose the correct diagnosis: