Primary CNS T-Cell Lymphomas: Clinical, Morphologic, Immunophenotypic and Molecular Analysis
Madhu P Menon, Armin Jegalian, Mark Raffeld, Stefania Pittaluga, Liqiang Xi, Elaine S Jaffe. National Cancer Institute/National Institute of Health, Bethesda, MD; Cleveland Clinic, Cleveland, OH
Background: Primary central nervous system (CNS) lymphomas are rare, accounting for 4% of primary brain tumors and 4-6% of extranodal lymphomas. The most common is diffuse large B-cell lymphoma. Primary CNS T-cell lymphomas account for <5% of the CNS lymphomas with few published case reports. We report on 9 cases of primary CNS T-cell lymphoma describing the age distribution, sex, morphology, immunophenotype and molecular characteristics.
Design: 9 cases were identified from consultation files of the Hematopathology section between 2004 and 2011; all cases were submitted as brain biopsies. Immunoperoxidase stains were performed as follows: CD2, CD3, CD4, CD8, CD5, CD7, β-F1, TIA1, Granzyme-B, Perforin and CD56. For T-cell receptor gamma (TRG) rearrangment, DNA was extracted from formalin-fixed paraffin-embedded tissue block and either 1) single multiplexed PCR was done with primers directed against all known Vg family members, and the Jg1/2, JP1/2 and JP joining segments or 2) two separate reactions were performed, one with primers Vg101, Vg11 and Jg12 (set 1) and a second with primers Vg 101, Vg11 and Jp12 (set 2). Products were analysed either via acrylamide gel electrophoresis or by capillary electrophoresis on ABI 3130xl Genetic Analyzer.
Results: All patients were males (median age of 57 years; range 21-81). In all cases, neoplastic cells were small to medium in size, with irregular nuclei. In two cases, there were few large cells with vesicular nuclei and prominent nucleoli. Areas of necrosis were seen in 5 cases. T cells had the following immunophenotype; CD3+ (9/9), CD2+ (5/6) with one case showing partial loss, TIA1+ (7/9), Granzyme-B+ (3/7) and CD56 neg (7/7). Perforin was negative in three cases analyzed. Regarding CD4 and CD8 immunostains, the findings were heterogeneous: CD4posCD8neg (2/9), CD4negCD8pos (3/9), CD4negCD8neg (2/9) and 2/9 patients had a mix of CD4 and CD8 positive cells. 5/9 cases were CD5+ (2 cases with partial loss) while 5/7 cases were CD7+ (1 case with partial loss). Regarding PCR analysis of TRG, 5/9 were clonal, 2/9 had suspicious clones, 1/9 was polyclonal and in 1 case there was no amplification.
Conclusions: Primary CNS T-cell lymphomas show a marked male predominance with a middle-age distribution. TIA-1 was positive in the majority, but other cytotoxic molecules were less often expressed. Loss of CD5 was the most common antigenic aberration, but all cases were negative for CD56. Clonality by TRG PCR was confirmative in the majority.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 196, Wednesday Morning