An indolent type of Epstein-Barr virus-associated T-cell-rich B-cell lymphoma of the skin: report of a case

Primary Cutaneous T-Cell/Histiocyte-Rich B-Cell Lymphoma: A Case Report and Literature Review

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a lymphoproliferative disorder in which the majority of cells are reactive T cells with only a minor population of neoplastic large B cells. THRLBCL is a very rare lymphoma, and most cases are nodal THRLBCL; an extranodal case of THRLBCL presenting primarily on the skin is an extremely rare occurrence with only a few cases reported in the literature. Here, we report a case of a primary cutaneous THRLBCL in a 41-year-old Saudi male who presented unusually with multiple skin lesions. He was successfully treated with electron beam radiotherapy and had a complete resolution with no recurrence as of his 24-month follow-up.

Cutaneous T-cell/histiocyte-rich B-cell lymphoma: a case report and review of the literature

BACKGROUND

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) primarily presenting on the skin is an extremely rare entity with only sporadic cases reported in the literature.

METHODS

We here report an extraordinary case of primary cutaneous THRLBCL with self-healing and 24 months of follow-up.

RESULTS

The lesion was a dermohypodermal/subcutaneous circumscribed ulcerated nodosity. Histological examination with immunohistochemical, molecular analysis and comparative genomic hybridization were performed. A complete staging was negative for secondary involvement.

CONCLUSION

Our case is remarkable because it is the second well-documented primary cutaneous THRLBCL in which we observed a complete self-regression of skin lesions without recurrences or dissemination of the disease. According to the literature, we highlight that the tumoral microenvironment, in our case, could play a relevant role in stopping lymphoma growth. Furthermore, this case supports the observation that THRLBCL primarily presenting on the skin shows an overall good prognosis.

Primary cutaneous T-cell-rich B-cell lymphoma in a zosteriform distribution associated with Epstein-Barr virus infection

T-cell-rich B-cell lymphoma (TRBL) is a lately recognized B-cell lymphoma variant characterized by a minor population of neoplastic B cells existing in a background of predominant polyclonal T cells. We report an 86-year-old man with primary cutaneous TRBL associated with Epstein-Barr (EB) virus infection. Clinically, palpable scaly erythemas were distributed in a zosteriform pattern on the right abdomen. Histologically, massive cellular infiltrates were located in the upper- and mid-dermis. Higher magnification showed that the cellular infiltration was composed mainly of abnormal mononuclear, large lymphoid cells with clear cytoplasm and scattered mitoses and small lymphocytes, which represented in excess of 75% of all the infiltrating cells. Immunohistochemical staining revealed that the large cells were positive for the B cell marker, CD20, but negative for the T cell marker, CD3. On the other hand, the small cells were positive for CD3, but negative for CD20. Polymerase chain reaction (PCR) revealed EB virus DNA in the skin lesion. Primary cutaneous TRBL has only been reported in 15 cases worldwide. To our knowledge, this is the first case of primary cutaneous TRBL in a zosteriform distribution reported in the literature and the second case of primary cutaneous TRBL associated with the EB virus infection. We postulate that the EB virus may be a contributory pathogenetic event leading to monoclonal B-cell proliferation.

Primary cutaneous T-cell-rich B-cell lymphoma: clinically distinct from its nodal counterpart?

The cases of two patients with Stage IE primary cutaneous T-cell-rich B-cell lymphoma (TCRBCL) are described. In both, the lesion showed a dense infiltrate by numerous small T lymphocytes with scattered histiocytes and large atypical B-lymphoid cells. Polymerase chain reaction assays demonstrated that the B cells were monoclonal, with immunoglobulin heavy-chain gene rearrangement. No clonal rearrangements of the T-cell receptor gamma gene were observed. Both patients were disease-free at 4 months and at 5 years after therapy, respectively. Although rare, primary cutaneous T-cell-rich B-cell lymphoma appears to have a better prognosis than its nodal counterpart, with or without skin involvement.

Molecular analysis reveals somatically mutated and unmutated clonal and oligoclonal B cells in T-cell-rich B-cell lymphoma

This paper describes the immunohistology and molecular genetics of 18 cases of T-cell-rich B-cell lymphoma (TCRBL). In all cases, the large B cells stained strongly for CD20, with more variable expression of CD79a, and were negative for CD30 and CD15. The majority of T cells were predominantly positive for TIA-1 and negative for CD57; a large population of histiocytes was present in all cases. Epstein-Barr virus (EBV)-coded RNA (EBER) was found in B blasts from four cases and in one case was present among the background lymphoid cells. IgH PCR products were generated in 16/18 cases and revealed clonal, oligoclonal and polyclonal PCR products in 12, two and two cases, respectively. In addition, TCRG clonal gene rearrangements were identified in two cases. TCRB gene rearrangements were polyclonal. Sequence analysis of seven cases with clonal/oligoclonal IgH gene rearrangements revealed functional sequences with predominant V(H)3 gene usage associated with various D genes and J(H)4 or J(H)6 gene segments. Four cases displayed varying degrees of replacement and silent mutations (1.8-21%), with one case exhibiting intraclonal heterogeneity; the distribution of mutations was indicative of antigen selection in three cases. The remaining three cases, including two cases with functional oligoclonal IgH rearrangements, harboured unmutated V region genes. The EBV-positive cases were associated with clonal, oligoclonal and polyclonal PCR products and with mutated and germline clonal sequences. These data indicate that TCRBL may be a heterogeneous entity associated with clonal and oligoclonal B cells derived from both germinal centre and naïve B cells.

Primary cutaneous T-cell-rich B-cell lymphomas with flow cytometric immunophenotypic findings. Report of 3 cases and review of the literature

BACKGROUND

Primary cutaneous T-cell-rich B-cell lymphoma is a relatively rare entity that has been diagnosed most commonly using immunohistochemical and molecular techniques. Flow cytometric immunophenotyping (FCI) has not been described in this entity. We report the demonstration of B-cell monoclonality by FCI in 3 cases of primary cutaneous T-cell-rich B-cell lymphoma.

METHODS

Clinical and pathologic data were recorded for 3 cases of primary cutaneous T-cell-rich B-cell lymphoma. Immunohistochemical and FCI data were available in all cases; DNA analysis was performed in 1 case.

RESULTS

Flow cytometric immunophenotyping revealed a monoclonal B-cell population exclusively in the monocyte (large cell) region in all 3 cases. Immunohistochemistry confirmed the T-cell richness of the infiltrates within the cutaneous lymphomas; T cells accounted for 65% to greater than 90% of the cells within the infiltrates. DNA analysis by polymerase chain reaction in 1 case did not demonstrate a monoclonal rearrangement of the immunoglobulin heavy-chain gene.

CONCLUSIONS

Flow cytometric immunophenotyping in primary cutaneous T-cell-rich B-cell lymphoma may be useful in demonstrating monoclonality in these cases, especially if there is selective gating on the relatively small population of cells in the large cell region. The FCI data should be correlated with histology and immunohistochemistry.