Primary Testicular NK/T-cell Lymphoma presented as testicular abscess: A Case Report and Literature Review of 33 cases

Primary testicular NK/T-cell lymphoma is rare. We report a 61-year-old Thai man who presented with right testicular abscess clinically but tissue obtained from incision and drainage was proven to be NK/T-cell lymphoma. The lymphoma cells were small to medium in size and showed angiocentricity with associated necrosis. The lymphoma cells were CD3+ (cytoplasmic), CD43+, CD56+, TIA-1+, Ki-67+ (nearly 100%) and EBV encoded RNA (EBER)+. Clinical staging was IE. CHOP chemotherapy and intrathecal methotrexate for primary CNS prophylaxis were administered with partial reduction of the testicular mass. However, 5.5 months after diagnosis, the patient developed left testicular enlargement and left facial palsy caused by leptomeningeal involvement. The patient died of progressive disease 9 months after diagnosis. The clinical course in this patient was aggressive, similar to those described in the literature review except for the uncommon CNS involvement. Based on 19 cases of primary testicular lymphoma (including the present case) and 15 cases of testicular involvement by NK/T-cell lymphoma elsewhere, the former seem to be less aggressive than the latter but the difference is not statistically significant in either overall median survival (32 vs. 16 weeks, p = 0.086) or mean survival (29.4 vs. 17.9 weeks, p = 0.083).