T-cell/histiocyte-rich diffuse large B-cell lymphoma. Report of a case diagnosed by fine needle aspiration biopsy with immunohistochemical and molecular pathologic correlation

BACKGROUND: T-cell-rich B-cell lymphoma (TCRBL) is a lymphoma of B-cell type associated with a prominent component of T cells (constituting > 50% of the cellular population). We report the first case of TCRBL diagnosed by fine needle aspiration (FNA). It was confirmed by subsequent lymph node excision biopsy. CASE: A 37-year-old woman presented with a short history of chest wall pain. Examination revealed induration, warmth and armorlike swelling of the right anterior chest wall, axilla and upper arm, with matted lymph nodes in the ipsilateral axilla and supraclavicular fossa. FNA showed a polymorphic, lymphoid aspirate, among which were many small lymphocytes, significant numbers of centroblastlike cells and a few markedly atypical lymphoid cells with convoluted nuclei. Histiocytes, freely lying karyorrhectic debris and mitotic figures were readily identified. Plasma cells, eosinophils and Reed-Sternberg cells were not seen. The cell block contained similar cells, with larger lymphoid cells scattered among smaller lymphocytes. Immunohistochemical studies showed that the larger cells were B cells. Molecular studies on the cell block confirmed an immunoglobulin gene rearrangement. CONCLUSION: TCRBL is a distinct type of lymphoma that can be accurately diagnosed by FNA.