[Primary Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma with Large Cell Transformation of the Prostate : A Case Report].

Primary mucosa-associated lymphoid tissue (MALT) lymphoma of the prostate is rare. MALT lymphoma with large cell transformation like a diffuse large B-cell lymphoma (DLBCL) of the prostate is extremely rare. To the best of our knowledge, only one case has been previously reported. A 65-year-old man with difficulty on urination was referred to our department, in April 2014, because of abnormal findings of magnetic resonance imaging (MRI) and positron emission tomography-computed tomography imaging. Routine laboratory tests including prostate specific antigen and soluble interletkin-2 recepter were within normal limits, and the physical examination was unremarkable. In July 2007 and August 2009, he was submitted for a transrectal prostate biopsy, and then a histological examination for chronic prostatitis. In addition to the biopsy, transurethral resection of the prostate was performed. Histological examination revealed primary MALT lymphoma with large cell transformation of the prostate. Complete clinical investigation, including bone marrow biopsy, did not show any involvement of other sites by lymphoma, he received 3 cycles of chemotherapy consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) followed by radiation therapy with a total dose of 46 Gy. The patient has been in complete remission for 6 months after the chemoradiation therapy.