An Unusual Case of Metachronous Tumors of Prostate and Parotid Gland: A Diagnostic Dilemma.

If diagnosed early, prostate cancer (PCa) has a good prognosis and an excellent five-year survival rate. However, this favorable behavior can be drastically worsened by the presence of another synchronous or metachronous higher-grade malignancy. In the current case report, we present and analyze a 76-year-old patient who underwent radical prostatectomy because of prostate gland adenocarcinoma, diagnosed on needle biopsy. The low Gleason score and the early stage of the PCa are in significant contrast with the widespread metastatic disease that is observed during the follow-up. Additional clinical examination, imaging, and histological evaluation reveal a high-grade salivary duct carcinoma, a metachronous primary in the left parotid gland. The presence of these two malignancies raises a series of diagnostic difficulties faced by medical professionals, in part because of the tendency of prostate gland and salivary gland tumors to show some overlapping features regarding their biological behavior and immunohistochemical aspects.