An extraordinary T/NK lymphoma, nasal type, occurring primarily in the prostate gland with unusual CD30 positivity: case report and review of the literature

Extranodal NK/T cell lymphoma(NKTCL), nasal type, occurring primarily in the prostate gland, is extremely rare. We present a case of primarily prostatic NKTCL in a 59-year-old man suffering from dysuria. Histological examinations revealed that diffused, large-sized, pleomorphic lymphocytes were arranged in an angiocentric distribution with large areas of geographic necroses. Additionally, the prostatic glands were diffusely infiltrated by heteromorphous lymphocytes forming lymphoepithelial lesions. The tumor cells were strongly expressed CD3ϵ, CD56, TIA-1, granzyme B and EBV-encoded RNAs. And interestingly, the lymphoid cells were also strongly immunoreactive with CD30. A rearrangement study showed T-cell receptor γ-chain gene rearrangement with monoclonal appearance. Though postoperative combination of chemotherapy was given, the patient died four months later. Our observation and other literatures indicate that extremely rare NKTCLs unusually express CD30. TCR gene rearrangement existed in some NKTCL, suggesting that a subset of NKTCL may be a mixed NK/T-cell differentiation.