American Urological Association - Lymphoma
- Lymphomas in prostate can be primary (35%) or secondary (48%).
- Diagnosis as primary requires that:1) lymphoma involves prostate with no or minimal involvement of periprostatic tissue; 2) symptoms are attributable to enlarged prostate; and 3) no involvement of hematopoietic system (peripheral blood, lymph nodes, liver or spleen) within 1 month of diagnosis.
- Incidental lymphoma may be seen in prostate with or without carcinoma.
- Symptomatic patients present mainly with obstructive urinary symptoms and occasionally with hematuria.
- Usually in men in their 60's.
- Cystoscopically, may show urethral luminal narrowing and bladder trabeculation indistinguishable from those seen secondary to BPH.
- Majority of incidental and concurrent (with known disease elsewhere) prostatic lymphomas are low-grade B-cell lymphomas.
- Most primary lymphomas are diffuse large B-cell lymphoma (55% of primary and 37% of secondary) and small lymphocytic lymphoma (18% of primary and 27% of secondary).
- Lymphomas tend to be diffuse and involve the fibromuscular stroma.
- In marginal zone lymphoma, lymphoid cells may infiltrate the prostatic acini and form characteristic lymphoepithelial lesions.
- DDX: chronic prostatitis, which mimics low-grade lymphomas.
- Unlike lymphoma, chronic prostatitis is composed of polymorphous cells (mature T and B cells, large activated B cells, plasma cells and histocytes), has infiltrates with pushing borders and often is periglandular in location.
- Immunohistochemistry: CD45, CD20 (for B cells) and CD3 (for T cells) will highlight lymphoid monoclonality (image D).
- Reported lymphoma specific 1 and 5 years survivals were 64% and 33%, respectively.