53 Year-Old Male with Massive Chest, Abdominal & Pelvic Adenopathy

Guy Nichols, M.D., Ph.D

Specimen Type:

Lymph Node

History:

A 53 year-old male presented with massive chest, abdominal and pelvic adenopathy. There was no known history of malignancy.

Pathologic Features:

Microscopic Findings:

A CT-guided, delicate core needle biopsy and subsequent, confirmatory lymph node excision demonstrated identical histologic features. Routine H&E sections and paraffin immunohistochemistry revealed effaced lymph node architecture consisting overwhelmingly of benign reactive CD3+ T cells. There were sparse, irregularly scattered, malignant appearing CD20+, PAX5+, bcl2+, bcl6+ large B cells. Negative staining for CD15 and CD30, as well as morphology argued strongly against classic Hodgkin lymphoma. Histologic features, including absence of nodularity and absence of progressively transformed germinal centers, argued against nodular lymphocyte predominant Hodgkin lymphoma, although the immunophenotype alone did not exclude this possibility.

Flow Cytometry:

Flow cytometry was noncontributory, since it characterized a >99% population of background T cells. Malignant large cells were most likely mechanically fragile and therefore even further underrepresented by flow cytometry. No light chain restricted, monoclonal B cell population was detected by flow cytometry.

Differential Diagnosis:

Malignant large B cell lymphoma, T-cell-rich B-cell subtype vs. nodular lymphocyte predominant Hodgkin lymphoma vs. benign reactive lymphoid hyperplasia.

Diagnosis:

Malignant large B cell lymphoma, T-cell rich B-cell subtype.

T-cell-rich B-cell lymphoma is an unusual variant of diffuse large B-cell lymphoma demonstrating histologic overlap with atypical reactive lymphoid hyperplasia (especially viral-induced), classic Hodgkin lymphoma and nodular lymphocyte predominant Hodgkin lymphoma. Histologically, it is characterized by a minor population of large, atypical B cells comprising less than 10% of total cells scattered within a predominant background population of reactive T cells. Paraffin immunohistochemistry typically excludes classic Hodgkin lymphoma, since tumor cells are CD15- and CD30-, but there is great phenotypic similarity to nodular lymphocyte predominant Hodgkin lymphoma. Attention to H&E histology as well as follicular dendritic cell architecture will distinguish T-cell-rich B-cell lymphoma from nodular lymphocyte predominant Hodgkin lymphoma in most but not all cases.

References:

  1. Nodular lymphocyte–predominant Hodgkin lymphoma with nodules resembling T-cell/histiocyte-rich B-cell lymphoma: differential diagnosis between nodular lymphocyte–predominant Hodgkin lymphoma and T-cell/histiocyte-rich B-cell lymphoma. Blood. 2003;102:3753-3758.