99mTc-HDP Bone Scintigraphy, SPECT/CT, and 18F-FDG PET/CT Diagnosis Imaging of Incidental Pleural Mesothelioma in a Patient With Biochemical Recurrences of Prostate Cancer: Is it Really a Coincidence?

We present the case of a 69-year-old man with history of prostate carcinoma treated with prostatectomy and subsequently with external beam radiotherapy and hormone therapy because of biochemical recurrences. More than 10 years after the diagnosis, follow-up Tc-HDP bone scans and SPECT/CT images demonstrated an incidental diagnosis of osteoblastic pleural plaques that quickly evolve to mesothelioma. PET/CT achieved the definitive diagnosis by guiding the biopsy to the highest and most accessible focus of glucidic hypermetabolism. Our case report raises the association between prostate cancer patients treated with external beam radiotherapy and the development of pleural mesothelioma despite having no history of exposure to asbestos.