[1285] CD5-Positive MALT Lymphoma: A Clinicopathologic Study of 9 Cases.

Jesse Jasso, Lei Chen, Pei Lin, Shaoying Li, Roberto N Miranda, L Jeffrey Medeiros, C Cameron Yin. UT MD Anderson Cancer Center, Houston, TX; UT Medical School, Houston, TX

Background: Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade B-cell lymphoma characterized by localized disease and an indolent clinical course. MALT lymphoma has a non-specific immunophenotype, often expresses pan B-cell markers but not CD5 or CD10. Scattered cases of CD5-positive MALT lymphoma have been reported. The clinicopathologic features remain incompletely described. We studied clinicopathologic features of 9 cases of CD5-positive MALT lymphoma to assess if these cases represent a distinct subtype of MALT lymphoma.
Design: We searched the database at our hospital for MALT lymphoma that was positive for CD5 by immunohistochemistry (IHC) and/or flow cytometry immunophenotyping (FCI). Clinicopathologic data were obtained from medical records. Cytogenetic analysis was performed on 4 cases.
Results: We identified 9 cases of CD5-positive MALT lymphoma that represent <1% of all MALT lymphoma at our hospital (5 men, 4 women, median age 68 years, range 34-87). MALT lymphoma was initially diagnosed in colon in 2, salivary gland in 2, skin in 2, lung in 1, lip in 1 and abdominal mass in 1. At presentation, 1 had localized disease; 8 had disseminated disease with multifocal lymphoma (n=6), lymphadenopathy (n=6), or bone marrow involvement (n=4). None presented with anemia, neutropenia, thrombocytopenia, lymphocytosis, monoclonal gammopathy, elevated LDH, B-symptoms or splenomegaly. ß2M was elevated in 3. Morphologically, the neoplasms had typical features of MALT lymphoma being composed of small to medium-sized cells with round to slightly irregular nuclei, dispersed chromatin and a moderate amount of cytoplasm. Lymphoepithelial lesions were noted in 2. CD5 was positive by IHC (8/8) and/or FCI (6/6). The lymphoma cells also expressed CD20 (9/9), CD19 (6/6), BCL-2 (4/4), CD22 (2/2), Pax-5 (2/2), CD23 (2/7) and CD43 (1/2). All were negative for CD10 and cyclin D1. Karyotypic analyses in 4 cases showed +3 in 2, t(3;17)(q27;q21) in 1 and diploid in 1. With a median follow-up of 70 months (range 14 to 114) in 7 patients with data available, 4/5 who required chemotherapy had progressive disease; the other was in remission. 2 patients had excision surgery and radiotherapy, respectively; both achieved remission. The overall survival at 5-years was 100%.
Conclusions: Our results show that CD5 positivity is a rare occurrence in MALT lymphoma, and is often associated with non-gastric disease and an increased tendency to present with disseminated disease. Overall survival is still excellent with appropriate therapy.
Category: Hematopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 196, Wednesday Afternoon


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