[1336] B-Cell Lymphoma Composite with T-Cell Malignancy: A Hidden Neoplastic Component; a Clinicopathological Study of 6 Cases.

Paulie Papavassiliou, Charles B Hutchinson, Imran N Siddiqi, Russell K Brynes, Endi Wang. Duke University Medical Center, Durham, NC; University of Southern California Medical Center, Los Angeles

Background: Composite Lymphoma (CL) is the occurrence of two or more lymphomas in a single anatomic site. These lymphomas arise from different clones and can appear simultaneously or sequentially. CLs involving both B and T cell lineages are a rare entity and have been described mostly as single case reports.
Design: We identified 6 cases of CLs by searching our institution's pathology database within the last 10-year period.
Results: Of the 6 cases, 5 are male. Ages range from 18 to 87 years, with median of 70.5. The 18-year-old male was a renal transplant recipient. The CL involved extranodal tissue in 5 cases, including skin (n=1), lung (n=2) and bone marrow (n=2). Of the T-cell component, peripheral T-cell lymphoma (PTCL-NOS) constitutes 5 cases and the remaining case is a T-cell large granular lymphocyte leukemia (T-LGL). Abnormal T-cells were detected by flow cytometry (n= 5), TCRG rearrangement (n=6) and immunohistochemistry (n=5). Of the B-cell component, large B-cell lymphoma (LBCL) comprises 3 cases, chronic lymphocytic leukemia-like small B-cell lymphoma (SBCL) occurs in 2 and hairy cell leukemia (HCL) in 1 (with T-LGL). Abnormal B-cells were detected by flow cytometry (n=2), IG gene rearrangement (n=5) and immunohistochemistry (n=5). Of the 3 LBCLs, all involved extranodal/extramedullary tissues, 2 demonstrated prominent plasmacytic differentiation and 2 were positive for EBV; none were detected by flow cytometry. The B-cell component was inconspicuous and cryptic in a background of overwhelming PTCL in 2 SBCLs and thus detected unexpectedly by flow cytometry. Although both neoplastic components presented in the same tissue, all cases involved multiple sites when the diagnosis of CL was established. All patients presented with clinical signs suggestive of malignancy except for one case of progressive anemia (HCL/T-LGL). Prognosis is difficult to assess due to insufficient follow-up. However, there is at least one known death.
Conclusions: CL tends to occur in older ages. PTCL-NOS is the predominant type of T-cell lymphoma, while LBCL is the main B-cell component. Most cases were in extranodal tissues, particularly LBCL composite with T-cell lymphoma. LBCL composite with T-cell lymphoma can be EBV positive, plasmacytoid and missed by flow cytometry. SBCL can be hidden by an overwhelming T-cell lymphoma. Therefore, a multifaceted analysis is recommended to identify masked components, particularly B-cell lymphoma.
Category: Hematopathology

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 225, Tuesday Morning


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