Primary diffuse large B cell lymphoma (DLBCL) of the prostate presenting with lower urinary tract symptoms (LUTS)

Abstract

Malignant lymphomas of the prostate are very rare tumours and are generally not considered in the clinical or pathological diagnosis of prostatic enlargement. We report a case of a 56-year-old man who presented with long-standing history of low back pain and a 2-month history of voiding lower urinary tract symptoms. He denied any history of urinary retention, trauma, catheterisation or any constitutional symptoms. Examination revealed no lymphadenopathy and hepatosplenomegaly. Digital rectal examination showed an irregular, moderately enlarged nodular prostate. His prostate-specific antigen was 1.54 ng/mL. MRI of the pelvis did not show any focal lesion apart from abnormal signal intensity in the central zone. Bone scan was negative. Transrectal ultrasound-guided prostate biopsy revealed diffuse large B cell lymphoma. Bone marrow biopsy and whole body positron emission tomography/CT were unremarkable. The patient achieved complete remission after receiving six cycles of R-CHOP chemotherapy.

Keywords: malignant and benign haematology; pathology; prostate; prostate cancer.

Figure 1

(A) T1-weighted and (B) T2-weighted MRI.

Figure 2

(A) Low-power magnification (10×) H&E: prostatic parenchyma exhibiting diffuse sheets of atypical lymphoid cells. (B) High-power magnification (40×) H&E: prostatic glands and stroma infiltrated by moderate to markedly pleomorphic and hyperchromatic lymphoid cells. (C) Immunohistochemistry (20×): CD20 immunostain showing diffuse strong membranous positivity. (D) Immunohistochemistry (20×): proliferation index (Ki-67): approximately 80% nuclear positivity.