Positron emission tomography/computerized tomography in the evaluation of primary non-Hodgkin's lymphoma of prostate

Abstract

Primary malignant lymphoma of the prostate is exceedingly rare. Here we report a case of a 65-year-old man who presented with increased urinary frequency, urinary urgency, and urinary incontinence for two years. Benign prostatic hypertrophy was suspected at primary impression. Ultrasound revealed a hypoechoic lesion of the prostate. The total serum prostate-specific antigen was within normal range. Positron emission tomography/computerized tomography (PET/CT) showed a hypermetabolic prostatic lesion. Prostate biopsy was consistent with a non-germinal center diffuse large B cell lymphoma. There was complete remission of the prostatic lesion following six cycles of chemotherapy as shown on the second PET/CT imaging. ¹⁸F-fluoro-deoxy glucose PET/CT is not only a complement to conventional imaging, but also plays a significant role in the diagnosis and evaluation of treatment response of prostatic lymphoma.

Keywords: Evaluation; Fluoro-Deoxy-Glucose; Non-Hodgkin’s lymphoma; Positron emission tomography/computerized tomography; Prostatic lymphoma.

Figure 1

Positron emission tomography/computerized tomography image. A: Whole body positron emission tomography (PET) image (scan) shows nodal hypermetabolic foci in the prostate, and no abnormally high uptake foci in the other sites of the body; B: The PET/computerized tomography (CT) fusion image displays a nodal hypermetabolic lesion located in the right lobe of the prostate, with maximal standardized uptake value (SUV) being 12.7; C: There were no hypermetabolic foci on the whole body PET imaging following six courses of chemotherapy; D: There was complete remission of the prostatic lesion after six cycles of chemotherapy, and the maximal SUV was 2.0.

Figure 2

Combined morphological and immunophenotyping examinations confirmed a diffuse large B cell lymphoma of non-germinal center B-cell origin. A: Intensive proliferation of lymphoid cells (Hematoxylin and eosin, × 400); B and C: Diffuse and consistent expression of CD79a, CD20 (immunohistochemistry, × 400); D: The expression of serum prostate-pecific antigen is negative (immunohistochemistry, × 400).