B-Cell Lymphoma

Abstract

A 70-year-old male presented to his primary care physician complaining of a left neck mass. He was otherwise healthy and asymptomatic. He was referred for fine needle aspiration to further characterize his neck mass. The fine needle aspiration revealed that the mass was an enlarged lymph node with an admixture of small lymphocytes and scattered highly atypical lymphoid cells consistent with lymphoma. Subsequently, an excisional biopsy was performed of the left neck lymph node. A touch preparation of the lymph node showed small mature lymphocytes and larger degenerated lymphoid cells. Sections of the node revealed a nodular proliferation of atypical lymphoid cells with an increased number of large atypical cells (Fig. 11.1). Flow cytometric immunophenotyping failed to identify any unique cell populations. Immunostaining for CD3 (pan T-cell marker), CD10 (common acute lymphoblastic leukemia antigen), CD20 (mature B-cell marker), CD21 (part of the B-cell coreceptor complex, positive on follicular dendritic cells), CD30 (marker of activated B and T cells), CD45 (leukocyte common antigen), CD57 (human natural killer-1 protein), and BCL2 (B-cell lymphoma-2 protein, antiapoptotic protein) was performed. The stains for CD3 and CD20 demonstrated that both B and T cells were present. CD3 stained many small lymphocytes within the nodules. CD20 stained both small and large atypical lymphoid cells. CD10 and CD21 highlighted the follicular dendritic network. In addition to staining for CD20, the large atypical cells also stained for CD30, CD45, and BCL2. CD57 positive cells were increased in the nodules but did not occur as a rim around the larger atypical cells.