The prostate is an interesting organ where only two diagnoses (Benign Prostatic Hyperplasia (BPH) and prostate cancer (PCa)) cover more than 95% of the cases where a prostate patient is seeing a urologist. Other specific diagnoses of the prostate such as metastatic disease from other organs or lymphoma of the prostate are extremely rare and suitable as case reports. BPH and prostate cancer are both cell growth-related disease entities, but their interaction is not well understood. In theory, there are three possible models of interaction: 1. BPH is precancerous (the more cell growth due to BPH, the higher the incidence of PCa); 2. There is no interaction between them (like migraine is not associated with the incidence of bone fractures); 3. BPH is protective of PCa (the larger the prostate due to BPH, the lower the incidence of PCa). No other options of interaction are possible. Although this is a clinically important question even lay people do understand, the official textbooks in Urology do not provide any definitive answers.