At a Glance

T-cell histiocyte rich large B-cell lymphoma (THRLB-CL) is considered a diffuse large B-cell lymphoma, but it is difficult to diagnose because of the paucity of large B-cells and the preponderance of T-cells and/or histiocytes. It is a rare lymphoma, accounting for less than 10% of diffuse large B-cell lymphomas and affects predominantly middle-age males (most reports indicate approximately 75% of patients are males). Unlike the typical diffuse large B-cell lymphoma, patients with THRLB-CL frequently present with bone marrow, liver, and spleen involvement and with systemic symptoms of fever and malaise.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

Diagnosis is often difficult, but is usually made on a biopsy of an enlarged lymph node or bone marrow. Because there are relatively few neoplastic large B-cells, flow cytometry on fresh tissue is frequently non-diagnostic. Immunohistochemistry studies performed on sections of paraffin embedded tissue are essential to demonstrate the large neoplastic cells as B-cells (CD20 positive) that are positive for CD45 (leukocyte common antigen). Frequently, a large panel of immunohistochemistry studies is needed to distinguish THRLB-CL from Hodgkin’s lymphoma, which may have a similar histologic appearance.

Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications – OTC drugs or Herbals – that might affect the lab results?

As indicated, morphologically, the differential diagnosis includes classical Hodgkin’s lymphoma, as well as nodular lymphocyte predominant Hodgkin’s lymphoma (NLPHL) and T-cell lymphoma. An extensive panel of immunohistochemistry studies is usually needed to distinguish between these entities.

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What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

The patient should be referred to an oncologist experienced in treating lymphomas. THRLBCL is considered an aggressive lymphoma, although a considerable amount of clinical variability is described. Once the diagnosis is made, staging includes imaging studies and a bone marrow biopsy performed to assess the extent of disease.