High levels of serum prostate-specific antigen due to PSA producing follicular non-Hodgkin's lymphoma

Objective: Both carcinoma of the prostate and non-Hodgkin's lymphoma are common in elderly patients. Measurement of serum prostate-specific antigen (PSA) is a frequently used tool to diagnose and monitor prostate carcinoma and is generally specific for diseases of the prostate. Case: We describe a 68-yr-old patient with voiding difficulties and high PSA levels, but without inflammatory or malignant changes upon multiple transrectal ultrasound guided prostate biopsies. Digital rectal examination was normal. Laboratory showed a strongly elevated PSA level (62 μg/L, Immulight 2000®; DPC, USA). A CT-scan showed a retroperitoneal process with mass in the right pelvis and infiltration of the bladder wall, suggestive for metastatic prostate carcinoma. Surgical excision of an axillary lymph node set the diagnosis at a stage IV follicular lymphoma, Berard grade I to II in which the majority of neoplastic cells expressed PSA. After lymphoma-specific treatment, there was a positron emission tomography (PET) confirmed complete remission with normal PSA levels (6 μg/L), which still persists. Conclusion: Although rare, high PSA levels can be due to the presence of non-Hodgkin's lymphoma. Such a diagnosis should be considered when patients present with lymphadenopathy other than regional prostatic lymphadenopathy.