[869] Lymphomas of the Genitourinary Tract: A Clinicopathologic Study of 40 Cases

SD Schniederjan, AO Osunkoya. Emory University School of Medicine, Atlanta, GA

Background: Lymphomas of the genitourinary tract are rare, comprising only 3% of all primary extranodal lymphomas. Few reports have been published describing the predominant sites and subtypes of genitourinary tract lymphomas. Further characterization of these rare neoplasms may contribute to a more complete understanding of the pathogenesis of the disparate entities of this heterogeneous disease category.
Design: We identified 40 patients with lymphomas of the genitourinary tract. H&E slides and immunohistochemical stains were reviewed.
Results: Mean age was 56 years (range 4-86 years). Among renal, bladder, and ureter lymphomas, a male predominance was noted (1.6:1). In most cases (25, 63%), the genitourinary tract was the site of initial presentation of lymphoma. The lymphoma subtypes observed were diffuse large B-cell lymphoma (19 cases, 48%); Burkitt lymphoma (5 cases, 12.5%); extranodal marginal zone lymphoma (4 cases, 10%), with one case arising within a myelolipoma; SLL/CLL (4 cases, 10%); follicular lymphoma (4 cases, 10%); pre-B ALL (2 cases, 5%); plasmacytoma, and T-cell lymphoma NOS (1 case, or 2.5% each). The kidney (15 cases, 37.5%) was the most frequent site of disease. Other affected sites included testis (9 cases, 22.5%), prostate (8 cases, 20%), bladder (5 cases, 12.5%), penis (2 cases, 5%), and ureter (1 case, 2.5%). Two patients eventually had involvement of more than one genitourinary site.
Conclusions: Genitourinary tract lymphomas most commonly occurred in the kidney. B-cell non-Hodgkin lymphomas predominated, with diffuse large B-cell lymphoma being the most common subtype. Extranodal marginal zone lymphoma was seen only in the kidney, rather than the bladder, where it is typically thought to be more common. Burkitt lymphoma was the second most prevalent subtype, and occurred most often in the kidney. This may reflect overrepresentation of pediatric and HIV-positive individuals in our institution's patient and referral base population, as Burkitt lymphoma is more prevalent in these groups. While this study confirms the predominance of diffuse large B-cell lymphoma in extranodal sites, the findings also highlight the variety of lymphomas that may occur in the genitourinary tract. This diversity of subtypes affirms the importance of fully characterizing lymphomas by immunohistochemistry and other modalities, which are indispensable for accurate diagnosis.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 1:00 PM

Poster Session II # 103, Monday Afternoon