Characteristics of CD5-positive splenic marginal zone lymphoma with leukemic manifestation ; clinical, flow cytometry, and histopathological findings of 11 cases

Incidental Splenic Marginal Zone Lymphoma With Extreme Macrocytosis After Hydroxyurea Use: A Case Report

Splenic marginal zone lymphoma (SMZL) is a low-grade mature B-cell lymphoma that typically presents in the form of splenomegaly and lymphocytosis. The diagnosis is traditionally made through splenic histology, the presence of circulating villous lymphocytes, or bone marrow biopsy. Its treatment can be in the form of chemotherapy, such as rituximab, or active surveillance. This case presentation discusses a 76-year-old female with a long history of hydroxyurea use for an unknown reason presenting with atypical symptoms requiring bone marrow biopsy to diagnose SMZL. This unique case demonstrates the importance of further research and studies into atypical SMZL presentations and hydroxyurea's potential in precipitating secondary malignancies.

Diagnostic challenges in an aggressive case of peripheralizing marginal zone lymphoma

B-cell lymphomas with atypical presentation or immunophenotype pose diagnostic challenges. Conventional ancillary tests (cytogenetics, FISH) can help, but have technical limitations. New technologies such as mate-pair sequencing (MPSeq) offer a route around these technical limitations.

Differential diagnosis of chronic lymphocytic leukemia/small lymphocytic lymphoma and other indolent lymphomas, including mantle cell lymphoma

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) accounts for approximately 1% of all lymphomas in our department. In this article, we describe the differential diagnosis of CLL/SLL from other indolent lymphomas, with special reference to follicular lymphoma, marginal zone B-cell lymphoma, lymphoplasmacytic lymphoma, and mantle cell lymphoma, although the latter is considered to be aggressive. CLL/SLL often exhibits proliferation centers, similar to follicular lymphoma. Immunohistological examination can easily distinguish these two lymphomas. The most important characteristic of CLL/SLL is CD5 and CD23 positivity. Mantle cell lymphoma is also CD5-positive and there are some CD23-positive cases. Such cases should be carefully distinguished from CLL/SLL. Some marginal zone lymphomas are also positive for CD5 and such cases are often disseminated. Lymphoplasmacytic lymphoma should also be a differential diagnosis for CLL/SLL. It frequently demonstrates MYD88 L265P, which is a key differential finding. By immunohistological examination, the expression of lymphoid enhancer-binding factor 1 is specific for CLL/SLL and can be a good marker in the differential diagnosis.

Prognostic significance of aberrant CD5 expression in B-cell leukemia

Aberrant expression of CD5 (as a T-cell marker) is seen in some leukemia and lymphoma of B lineage origin. Given that the signaling resulting from the expression of this marker plays an essential role in the development of leukemia and lymphoma, evaluating the expression of this marker is of paramount importance. Therefore, our goal in this study was to investigate the prognostic importance of CD5 expression in B-cell leukemia and lymphoma. We evaluate CD5 expression in normal and leukemic B-cells by identifying relevant literature through a PubMed search (1998-2018) of English language papers using the terms: ‘CD5,’ ‘B-cell,’ ‘Leukemia,’ and ‘Lymphoma.’ We are doing this thorough comparison of results from CD5 positive and negative cases to make a correct decision about prognostic importance of CD5 expression in these malignancies. In a number of B-cell malignancies, CD5 is expressed in varying degrees. Due to the different origins and characteristics of these malignancies, the results of CD5 expression evaluations are heterogeneous and impossible to generalize. However, CD5 expression is sometimes associated with clinicopathologic findings, more invasive clinical course, and even resistance to treatment (specifically in DLBCL) among CD5- positive patients, which appears to be a function of CD5 signaling and its downstream factors such as STAT3. Depending on the type of malignancy, CD5 expression is associated with good or bad prognosis, which can be used as an auxiliary prognostic factor to assess the clinical course of B-cell malignancies. Moreover, the difference in expression levels of CD5 in a variety of B-cell malignancies allows for differential diagnosis of these malignancies, which can be helpful when diagnosis is difficult.

Splenic B-Cell Lymphomas with Diffuse Cyclin D1 Protein Expression and Increased Prolymphocytic Cells: A Previously Unrecognized Diagnostic Pitfall

Prolymphocytic transformation is a concept usually applied in the context of chronic lymphocytic leukemia/small lymphocytic lymphoma to describe the presence of a high percentage of prolymphocytes in peripheral blood (usually more than 55%). Prolymphocytic transformation has also been reported in mantle cell lymphoma (MCL) but only rarely in splenic marginal zone lymphoma (SMZL). We present two splenic B-cell lymphomas presenting in the leukemic phase and with increased prolymphocytes, both classified as SMZL with prolymphocytic transformation. One case clinically simulated B-prolymphocytic leukemia (B-PLL). Both lymphomas were very unusual because the tumor cells diffusely and strongly expressed cyclin D1 despite lacking the t(11; 14)(q13; q32) as detected by several approaches including next-generation sequencing, fluorescence in situ hybridization using CCND1 break apart probe and fusion probes for t(11; 14)(q13; q32), and conventional karyotyping. These cases therefore simulated prolymphocytic variants of MCL. The incidence of this phenomenon is unknown, and awareness of this potential alternate protein expression pattern is important in order to avoid diagnostic errors.

Successful Treatment of Leukemic Mature B-Cell Lymphoid Neoplasm with Similar Features to Splenic Marginal Zone Lymphoma Possessing Aberrant Myeloid Markers

In splenic marginal zone lymphoma (SMZL), there are cases that cannot accurately be classified as such because of overlapping morphologic and/or immunophenotypic features. We report here a 76-year-old Japanese female, who showed leukemic B-cell lymphoproliferative disease possessing characteristic features identified for SMZL. The patient was leukemic with white blood cell counts 49,400/µL (abnormal cells, 78.5%) and neoplastic cells were characterized by aberrant expression of myeloid markers with CD19⁺CD13⁺ (64.2%) and CD20⁺CD11c⁺ (25.1%). Considering her history of previous chemotherapy and systemic leukemic phase of the disease, we treated the patient without performing splenectomy, with successful use of a combination of rituximab/bendamustine hydrochloride and of rituximab/cladribine. The patient has been in a complete remission longer than 44 months, with no detectable M-protein.

Flow cytometric analysis of lymphoid enhancer-binding factor 1 in diagnosis of chronic lymphocytic leukemia/small lymphocytic lymphoma

OBJECTIVES

Nuclear overexpression of lymphoid enhancer-binding factor 1 (LEF1) assessed by immunohistochemistry has been shown to be highly associated with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) among small B-cell lymphomas. The purpose of this study was to evaluate the utility of flow cytometric analysis of LEF1 in the diagnosis of CLL/SLL.

METHODS

Normal peripheral blood was used to validate the test. Flow cytometric analysis of LEF1 was performed in 64 patient samples qualitatively and quantitatively by comparing the staining intensity and the ratios of the median fluorescence intensities (MFIs) of LEF1 in B cells of interest to the internal reference cell populations. The results were correlated with the pathologic diagnosis.

RESULTS

Proper sample processing ensured sufficient separation of positive LEF1 staining in T cells from negative staining in normal B and natural killer (NK) cells. Qualitative analysis of patient samples showed that all 25 cases of CLL/SLL but none of the other small B-cell lymphomas were positive for LEF1. Using a B/NK MFI ratio of 1.5 and B/T MFI ratio of 0.45 separated CLL/SLL cases from non-CLL lymphomas.

CONCLUSIONS

Flow cytometric analysis of LEF1 is sufficient to differentiate CLL/SLL from other small B-cell lymphomas and may serve as a useful tool in the diagnosis of CLL/SLL.

Clinicopathologic features of CD5-positive nodal marginal zone lymphoma

OBJECTIVES

To describe the clinicopathologic findings of seven patients with CD5-positive nodal marginal zone lymphoma (NMZL).

METHODS

We searched cases of NMZL over a 10-year interval and identified seven cases of CD5-positive NMZL. The clinical, histologic, and immunophenotypic findings of this group were reviewed, and the frequency of dissemination in this group was compared with that of 66 patients with CD5-negative NMZL.

RESULTS

Other than CD5 expression, the histologic and immunophenotypic findings were typical of NMZL. Six (86%) of seven patients had lymphadenopathy above and below the diaphragm, and all six patients assessed had bone marrow involvement. In the CD5-negative group, 28 (42%) patients had lymphadenopathy above and below the diaphragm, and 36 (55%) had bone marrow involvement (P = .045 and P = .037, respectively). Six of seven patients were alive at last follow-up, with a median follow-up of 32 months (3-154 months).

CONCLUSIONS

CD5 expression in NMZL correlates with a higher frequency of dissemination, but patients have an indolent clinical course and excellent overall survival.

Tissue flow cytometry immunophenotyping in the diagnosis and classification of non-Hodgkin's lymphomas: a retrospective evaluation of 1,792 cases

A retrospective analysis of 1,792 solid tissues suggestive of lymphoma, submitted over a 12-year period, was carried out and flow cytometry (FC) results were compared with histologic findings. The final histologic diagnosis of cases documented in this report is as follows: 1,270 non-Hodgkin's lymphomas (NHL); 17 composite lymphomas; four NHL plus carcinomas; five post-transplant lymphoproliferative disorders; 105 Hodgkin's lymphomas (HL); eight acute leukemias; 42 tissue cancers; and 341 non-neoplastic diseases. A strong correlation between morphology and FC data was observed among hematological malignancies (1,268/1,304, 97.2%) with the exception of HL. Among B-NHL, FC detection of clonally restricted B-cell allowed the identification of lymphomas that were not histologically clear and the differential diagnosis between follicular lymphoma and reactive hyperplasia. A high correlation level (r = 0.83; P < 0.0001) was obtained in comparing proliferation results obtained by FC and immunohistochemistry. Among T-NHL, FC detection of an aberrant phenotype direct histologic diagnosis in cases having less than 20% of neoplastic cells. In nine cases, FC suggested the need to evaluate a neoplastic population, not morphologically evident. Results show that FC routinely performed on tissue samples suspected of lymphomas is a fundamental adjunct to morphology in the diagnosis of NHL and may enhance the performance of the histologic evaluation so as to achieve the final diagnosis. To the best of our knowledge, this is the first report in the literature of a wide series of tissues also studied by FC.

Extranodal and splenic small B-cell lymphoma

Although almost any non-Hodgkin lymphoma can involve the spleen or an extranodal site as part of more widely disseminated disease, there is a group of small B-cell lymphomas that specifically arise in these locations. These are important to recognise as some appear to have a behaviour and prognosis that is distinct from their nodal counterparts. In addition, there are entities that are specific to extranodal locations (such as extranodal marginal zone lymphoma) and to the red or white pulp of the spleen. In this review, the characteristics of these entities will be presented as well as clues to help distinguish lymphoma from reactive infiltrates in extranodal sites and measure to distinguish between small B-cell lymphomas encountered in the spleen and at extranodal locations.