Case Report Primary Lymphoma of the Prostate Primary Prostate Lymphoma Presented as Urinary Retention in a Young Male Patient: A Case Report Wei-Ching Lee, Po-Hui Chiang Department of Urology, Kaohsiung Medical Center, Chang Gung Memorial Hospital, and Chang Gung University, Kaohsiung, Taiwan We report a rare case of a primary malignant lymphoma of the prostate, which presented as urinary retention in a 32-year-old male patient. A digital rectal examination revealed an enlarged hardly prostate. B-cell lymphoma arising in the prostate was diagnosed by a prostate biopsy and confirmed by an immunohistochemical examination. The patient received doxorubicin-based combination chemotherapy, which showed a good outcome in terms of both decreasing the size of the tumor and improving the associated symptoms during 9 months of follow-up. To our knowledge, there are only a few reported cases of a primary malignant lymphoma arising in the prostate. We recommend that the digital rectal examination be used in young male patients who reveal abnormal urinary voiding function. (JTUA 20:86-8, 2009) Key words: malignant lymphoma, B-cell lymphoma, prostatic neoplasm. INTRODUCTION To the best of our knowledge, there have only been a few large-series studies on malignant lymphomas involving the prostate. A primary malignant lymphoma of the prostate is especially rare, and represents 0.09% of prostate neoplasms and 0.1% of all non-Hodgkin lymphomas.1 Moreover, this type of lymphoma tends to occur in elderly men at an average age of 62 years.2 We report a case of primary lymphoma of the prostate in a young male patient who presented with urinary retention. The diagnosis was confirmed by histopathology and a series of other examinations. The patient was treated with doxorubicin-based combination chemotherapy, which showed a good outcome. there was no significant abnormality. Blood tests revealed a prostate-specific antigen (PSA) level of 3.63 ng/ml and serum creatinine level of 1.0 mg/dl. Transrectal ultrasonographic imaging of the prostate revealed an irregular contour with homogenous echogenicity, and the volume of the prostate measured 77 ml. The patient underwent needle biopsy of the prostate under transrectal ultrasonographic guidance. A malignant prostate tumor was confirmed by the histopathological examination, and the tumor cells immunostained positively for T200, CD20 (Fig. 1), and neuron-specific enclose (NSE). Hence, the malignant lymphoma was CASE REPORT A 32-year-old male patient visited our hospital complaining of difficulty in urinary voiding for several months, which led to urinary retention that was restored by Foley catheterization. The patient underwent a digital rectal examination, and a large prostate with a hard consistency was palpated. Urine analysis showed that Address reprint requests and correspondence to: Po-Hui Chiang, MD Department of Urology, Chang Gung Memorial Hospital, 123 Ta-Pei Rd., Kaohsiung 807, Taiwan Tel: 886-7-7317123 E-mail: cphtem@yahoo.com.tw US Fig. 1. Positive CD20 stain (400×). JTUA 2009 20 No. 2 W. C. Lee, et al confirmed to be of B-cell lineage. We then performed an abdominal and pelvic computed tomographic (CT) scan; the scan revealed a large tumor in the prostate gland, which extended into the posterior wall of the bladder (Fig. 2A). However, there was no evidence of any systemic lymph node enlargement. Subsequently, a bone marrow biopsy of the left iliac crest was performed; no lymphomatous involvement was observed. Since the patient was diagnosed with a primary malignant lymphoma of the prostate, he received 6 courses of cyclophosphamide, hydroxydoxorubicin, oncovin (vincristine), and prednisolone (CHOP) combination chemotherapy. The patient was able to void urine without difficulty, and hence the Foley catheter was removed after the second course of CHOP chemotherapy. A CT scan performed during the followup revealed tumor size reduction (Fig. 2B). The size of the prostate measured by transrectal ultrasonographic imaging was originally 77 ml (Fig. 3A) and had decreased to 16 ml (Fig. 3B) after 8 months. DISCUSSION A primary malignant lymphoma of the prostate is very rare and difficult to distinguish from other diseases of the prostate. To our knowledge, there have been no large-series studies of this condition except for a few case reports.3,4 Approximately 40% cases of lymphoma involve extranodal organs, including the gastrointestinal tract, skin, kidney, bone, and other organs and tissues. Moreover, primary and secondary lymphomas involving the prostate are often found in elderly male patients. We report a case of a 32-year-old male patient, who presented with a feature of urinary obstruction, and subsequently, a primary lymphoma of the prostate was confirmed. Taking into consideration the complications of radical surgery and/or radiotherapy,5 such as incontinence and/or erectile dysfunction, we prescribed chemotherapy for this young patient. The patient received 6 courses of CHOP chemotherapy,6 which led to marked tumor size reduction and restoration of good urinary A A B B Fig. 2. CT scan. (A) Before treatment; (B) after treatment. JTUA 2009 20 No. 2 Fig. 3. Transrectal ultrasonogram. (A) Before treatment; (B) after treatment. UT Primary Lymphoma of the Prostate voiding function. On the basis of the outcome of this case, we can predict that young men can suffer from a primary lymphoma of the prostate. Although hematuria is sometimes present in young patients,7 lower urinary tract symptoms (LUTS) are the most frequent clinical obstruction in cases of tumor infiltration that lead to an increase in prostate volume.8 Evaluation of the prostate by a digital rectal examination is important for any male patient presenting with LUTS, especially patients with a normal serum PSA level. This patient had consulted several urologists, who misdiagnosed his condition as prostatitis, since a digital rectal examination was not performed. At a time when PSA can be used as a tumor marker, the importance of a digital rectal examination cannot be overemphasized. If a digital rectal examination and imaging study indicate the presence of a prostate neoplasm, the differential diagnosis includes benign prostate hyperplasia, carcinoma or sarcoma of the prostate or bladder, and prostate abscess or tuberculosis.9 The diagnosis is dependant on a histopathological examination. In the literature, almost all primary lymphomas were diagnosed with transurethral resection of the prostate (TURP). However, it was not performed in this patient since TURP may cause complications such as retrograde ejaculation. Thus, we recommend a prostate biopsy instead of TURP for young male patients. The prognosis of a prostate lymphoma is poor, and no long-term disease-free survival has been documented.10 However, our patient was relieved of urinary symptoms with normalization of the prostate size and has led a disease-free life for 9 months until the time of this writing. Long-term follow-up is required to evaluate the outcome of a pri- UU mary lymphoma of the prostate in young patients who undergo the CHOP regimen treatment. REFERENCES 1. Sarris A, Dimopoulos M, Pugh W, Cabanillas F. Primary lymphomas of the prostate: good outcome with doxorubicin-based combination chemotherapy. J Urol 1995; 153:1852-4. 2. Bostwick DG, Iczkowski KA, Amin MB, Discigil G, Osborne B. 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