Rare Presentation of Prostate Cancer Mimicking Malignant Lymphoma with Generalized Lymphadenopathy

Prostate cancer typically metastasizes to bones and regional lymph nodes. Generalized lymphadenopathy is a rare manifestation of metastatic prostate cancer. We report a case of prostate cancer in a 65-year-old male with initial presentation of generalized lymphadenopathy and no urinary symptoms. Lymph node biopsy revealed metastatic adenocarcinoma, and immunohistochemical staining was positive for prostate-specific antigen (PSA) compatible with a prostatic origin. Directed biopsy confirmed that the tumor originated in the prostate. Therefore, the prostate should be considered a possible origin of metastatic adenocarcinoma in men, and presentations consistent with generalized lymphadenopathy cannot exclude a diagnosis of prostate cancer.