Discordant Radiologic and Biochemical Response With Inflammatory Activity in Metastatic Prostate Cancer: A Case Report.

Discordance between imaging findings and biochemical markers represents a significant diagnostic and therapeutic challenge in metastatic prostate cancer. We report the case of a 72-year-old male with high-risk prostate adenocarcinoma (Gleason 4+5=9) and extensive bone metastases, who demonstrated partial radiologic and metabolic response on prostate-specific membrane antigen PET/CT and single-photon emission CT/CT imaging following systemic therapy while simultaneously exhibiting rising prostate-specific antigen levels and elevated systemic inflammatory markers. Despite imaging-defined response, CT revealed persistent mixed osteoblastic and osteolytic bone lesions, suggesting underlying biological heterogeneity and asynchronous tumor behavior. This discordant pattern indicates that radiologic improvement may not fully reflect ongoing systemic disease activity. This case supports the hypothesis that systemic inflammatory activity, in conjunction with biochemical progression, may reflect early tumor-host interaction and emerging treatment resistance, potentially preceding overt radiologic progression. These findings underscore the need for integrated, multimodal monitoring strategies combining imaging, biochemical, and inflammatory markers to better capture dynamic disease activity and enable earlier detection of treatment resistance in metastatic prostate cancer.