Small Cell/Neuroendocrine Prostate Cancer: A Rare Treatment-Resistant Variant Presenting as Acute Onset Severe Back Pain.

Adenocarcinoma of the prostate is the most frequent subtype of prostate cancer. Being an androgen-driven disease, androgen deprivation therapy (ADT) is one of the mainstay treatments for prostatic adenocarcinoma. ADT however can induce androgen resistance and can cause neuroendocrine differentiation of the cells and subsequently can lead to the emergence of neuroendocrine prostate cancer (NEPC). NEPC, despite being rare, is very aggressive with a very low survival period. The majority of the NEPC cases are treatment-emergent. There is no definite guideline on screening for the development of NEPC for patients who are on ADT. Our case highlights the lethality and aggressiveness of NEPC and the relationship between ADT and NEPC. More research is needed to compare different imaging techniques for early detection and identification of NEPC and to establish screening protocols for patients at risk of developing NEPC while on ADT.