Rationale: About 95% of prostate cancers are adenocarcinoamas. Depending on the detection method used, neuroendocrine cells are found in 10% to 100% of prostate cancer specimens.

Objective: A 64-year-old patient was diagnosed in 2006 with adenocarcinoma of the prostate, PSA 4.1 ng/ml, Gleason 6, T3b, positive PSA immunohistochemistry.

Methods and results: The patient was started on hormone therapy: orchidectomy followed by flutamide 750 mg/day for three years, and underwent radiotherapy 6400 R. The patient was asymptomatic for three years. In 2009, the patient complained of perineal and rectal pain, but the PSA remained normal. In 2010, the patient underwent TUR of the prostate for acute urinary retention. Pathological exam revealed Gleason 8 adenocarcinoma of the prostate (different pathologist suggested Gleason 9) and foci of neuroendocrine cells. Immunohistochemistry detected 15-20% positivity for Cromogranin A and 10% for synaptophysin. The patient developed multiple liver metastases in October 2010 and underwent five cycles of etoposide, carboplatin. The patient died of liver failure in March 2011.

Discussion: Regarding prevalence, neuroendocrine differentiation is the second phenotype after prostate adenocarcinoma, but still remains undiagnosed. It is resistant to radiation therapy and chemotherapy. Detection of the neuroendocrine differentiation is recommended during the clinical, biochemical, histopathological and immunohistochemical follow up of prostate cancer patients treated by EBRT and / or androgen deprivation.

Abbreviations CT computerized tomography; MRI magnetic rezonance imaging; NE neuroendocrine; NSAID nonsteroidal anti-inflamatory drug; PSA prostatic specific antigen; EAU European Association of Urology; PET Positron Emission Tomography; EBRT external beam radioyherapy