Dual-tracer positron emission tomography (PET) imaging with <sup>18</sup> F-FDG-PET/computed tomography (CT) and <sup>68</sup> Ga-PSMA-11 PET/CT showed complete response of prostatic adenocarcinoma with controlled serum prostate-specific antigen level, showed new-onset metastatic brain and liver lesions 12 months later, the biopsy of the later revealed metastatic small cell neoplasia. Here, KLK3 is linked to prostate adenocarcinoma.