Follicular Colonization of Nodal Marginal-Zone B-Cell Lymphoma Resembling Follicular Lymphoma: Report of 6 Cases

Study of the Utility of Myeloid Cell Nuclear Differentiation Antigen (MNDA) in the Diagnosis of Marginal Zone Lymphoma

Myeloid cell nuclear differentiation antigen (MNDA) is normally expressed on myelomonocytic cells and a subset of B lymphocytes. It was found to be differentially expressed between nodal marginal zone lymphoma (MZL) and follicular lymphoma (FL). However, MNDA has not been widely used as a diagnostic marker in clinical practice. To validate its utility, we studied the expression of MNDA by immunohistochemistry in 313 cases of small B-cell lymphomas. Our results showed that MNDA was positive in 77.9% of MZL, 21.9% of mantle cell lymphoma, 28.9% of small lymphocytic lymphoma/chronic lymphocytic leukemia, 2.6% of FL, and 25% of lymphoplasmacytic lymphoma. MNDA positivity varied from 68.0% to 84.0% among the 3 MZL subtypes, with extranodal MZL having the highest percentage. There was a statistically significant difference in MNDA expression between MZL and FL, mantle cell lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia, or lymphoplasmacytic lymphoma. CD43 expression was slightly more frequent in MNDA-negative MZL than in MNDA-positive MZL. Combined use of CD43 and MNDA improved the diagnostic sensitivity for MZL from 77.9% to 87.8%. There was a trend of positive correlation between MNDA and p53 in MZL. In conclusion, MNDA is preferentially expressed in MZL among small B-cell lymphomas and it is a useful marker for the differentiation of MZL and FL.

Adult Nodal Burkitt Lymphoma Forming Nodular Architectures

In this report, we discuss a case of nodal Burkitt lymphoma seen in a 60-year-old Japanese male patient. Microscopic features of the biopsied 30 mm-sized cervical lymph node revealed nodular architectures with starry sky appearance surrounded by small mantle zone B-lymphocytes. Immunohistochemical and molecular studies demonstrated typical features of sporadic Burkitt lymphoma: the atypical cells were positive for CD20, CD79a, CD10, CD23, HLA-DR, bcl-6, PAX5, c-myc, and cytoplasmic IgM, but negative for CD3, CD5, CD15, CD30, CD34, TdT, bcl-2, and MUM1. The mantle zone B-cells were clearly positive for bcl-2 and IgD. In situhybridization (ISH) analysis for immunoglobulin light chains showed kappa-type monoclonality. A few nuclei were labeled for Epstein-Barr virus-encoded small nuclear RNA (EBER). Ki-67 labeling index was nearly 100%. Within the nodule, CD21, CD23, and CD35-positive follicular dendritic cells were scattered with a small number of CD3/CD5-positive small T-lymphocytes, indicating that the nodular architecture represented follicular colonization of Burkitt lymphoma cells. Karyotypic analysis revealed t(8;14)(q24;q32), and IGH-MYC fluorescence in situ hybridization (FISH) demonstrated IGH-MYC fusion signals. The presentation of follicular colonization was quite unique in Burkitt lymphoma in the present case. Differential diagnosis is also discussed.

CD10 down expression in follicular lymphoma correlates with gastrointestinal lesion involving the stomach and large intestine

Follicular lymphoma (FL) shows co-expression of B-cell lymphoma 2 (BCL2) and CD10, whereas downexpression of CD10 is occasionally experienced in gastrointestinal (GI) FL with unknown significance. Gastrointestinal FL is a rare variant of FL, and its similarity with mucosa-associated lymphoid tissue lymphoma was reported. We investigated the clinicopathological and genetic features of CD10 downexpressed (CD10^down ) GI-FL. The diagnosis of CD10^down FL was carried out with a combination of pathological and molecular analyses. The incidence of CD10^down GI-FL was shown in 35/172 (20.3%) cases, which was more frequent than nodal FL (3.5%, P < 0.001). The difference was additionally significant between GI-FL and nodal FL when the analysis was confined to primary GI-FL (55.2% vs 3.5%, P < 0.001). Compared to CD10⁺ GI-FL, CD10^down GI-FL significantly involved the stomach or large intestine (P = 0.015), and additionally showed the downexpression of BCL6 (P < 0.001). The follicular dendritic cell meshwork often showed a duodenal pattern in the CD10^down group (P = 0.12). Furthermore, a lymphoepithelial lesion was observed in 5/12 (40%) gastric FL cases, which indicated caution in the differentiation of mucosa-associated lymphoid tissue lymphoma. Molecular analyses were undertaken in seven cases of CD10^down GI-FL, and an identical clone was found between CD10^down follicles and CD10⁺ BCL2⁺ neoplastic follicles. In the diagnosis of cases with CD10^down BCL2⁺ follicles, careful examination with molecular studies should be carried out.

Richter syndrome with follicular colonization of chronic lymphocytic leukemia/small lymphocytic lymphoma cells mimicking follicular lymphoma

Follicular colonization is occasionally observed in marginal zone lymphoma. In rare cases, it has also been associated with mantle cell lymphoma. Chronic lymphocytic leukemia typically involves nodal or extranodal tissues as diffuse proliferation by complete effacement of the normal architecture. The involvement of chronic lymphocytic leukemia may be less frequently limited to the interfollicular areas. Here, we report a case of Richter syndrome of the small intestine that was initially diagnosed as follicular lymphoma of the gastrointestinal tract because of a partial follicular growth pattern in addition to a mainly diffuse proliferation pattern. The follicular pattern mimicking follicular lymphoma was shown to be composed of reactive follicles with follicular colonization of the original chronic lymphocytic leukemia cells. As the prognoses of Richter syndrome and follicular lymphoma of gastrointestinal tract are quite different, clinicians must carefully diagnose these conditions to avoid a misdiagnosis.

Nodal marginal zone B cell lymphoma with prominent follicular colonization with deletion of chromosome 13

Nodal marginal zone B cell lymphoma is a rare type of malignant lymphoma and appears to be heterogeneous. Here we report a 60-year-old woman with stage I splenic type of nodal marginal zone B cell lymphoma with prominent follicular colonization. She was treated only by radiation therapy, and remained free of disease on examination for 4 years. The lymph node cells showed an abnormal chromosome of deletion 13, although neither bone marrow cells nor peripheral blood cells demonstrated the same abnormal chromosome. This type of chromosomal abnormality has not been previously reported and may be related to good prognosis in the present case.

Follicular lymphoma of the thyroid gland

The majority of lymphomas arising in the thyroid gland are mucosa-associated lymphoid tissue lymphomas and diffuse large B-cell lymphomas, which arise from a background of chronic lymphocytic thyroiditis. Follicular lymphoma may also present in the thyroid gland, but its clinicopathologic features at this site are not well characterized, leading to difficulties in diagnosis and clinical management. We have addressed this problem by studying the clinical, morphologic, immunophenotypic, and genetic features of 22 such cases. All cases showed morphology characteristic of follicular lymphoma, however, in many the interfollicular neoplastic infiltrate was particularly prominent and all lymphomas contained readily identifiable and often striking lymphoepithelial lesions, features heretofore considered indicative of mucosa-associated lymphoid tissue lymphoma at this site. Furthermore, 13 of 18 cases for which sufficient evidence was available had clinical and/or histologic evidence of chronic lymphocytic thyroiditis. Analysis of genetic and immunohistochemical features identified 2 distinct groups. In 1 group, similar to typical adult follicular lymphoma, cases carried a t(14;18)/IGH-BCL2 and/or expressed Bcl-2, and were mostly CD10-positive and of World Health Organization (WHO) grade 1 to 2. Follicular lymphomas in the other group lacked IGH-BCL2 and Bcl-2 expression, were often of WHO grade 3 and were often CD10-negative, similar to the minority of follicular lymphomas previously described that are Bcl-2-negative and are often encountered at other extranodal sites. The 2 groups differed in clinical stage at presentation, 11 patients in the former group but none in the latter group having disease beyond the thyroid gland. Appreciation of the spectrum of morphologic, immunophenotypic, and genetic characteristics of follicular lymphoma presenting in the thyroid gland should aid both diagnosis and clinical management.

Significance of C4d deposition in the follicular lymphoma and MALT lymphoma and their relationship with follicular dendritic cells

We evaluated the deposition of C4d in follicular lymphomas (FL) and extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma). Deposition of C4d was detected in 118 lymphoma tissues from patients with lymphoma and in 20 reactive hyperplasia lymphadens (RHL) using immunohistochemistical methods. FL, MALT lymphoma, and RHL were studied using double staining for CD35/C4d and Bcl-2/C4d. We studied 26 FL tissues, 19 of which showed C4d deposition. C4d deposition was detected around the follicular dendritic cells (FDCs) in the neoplastic follicles. There was no significant difference between the positive ratio of C4d and the grades of FL. We studied 12 MALT lymphoma tissues, six of which displayed C4d deposition. In these tissues, C4d deposition was detected in the peripheral region of partially colonized follicles in the form of an irregular ring, but was not found in the central region. C4d deposition was negative in completely colonized follicles. There was no C4d deposition in diffuse large B-cell lymphomas, mantle cell lymphomas, B-small lymphocytic lymphomas, T-lymphoblastic lymphomas, peripheral T-cell lymphomas, and anaplastic large cell lymphomas. C4d around the FDCs in the neoplastic follicles was a specific indicator for FL. C4d deposition in partially colonized follicles of MALT lymphoma was completely different from that in neoplastic follicles of FL, forming a key point for differential diagnosis.

Clinical implications of nodal marginal zone B-cell lymphoma among Japanese: study of 65 cases

To clarify the clinical presentation and outcome of nodal marginal zone B-cell lymphoma (NMZBL), 65 Japanese patients with this disease were studied and compared with the published literature from western countries. The clinical findings of our 65 cases were similar to those of their cases in some aspects: (1) 58% of the patients were > 60 years old (median age, 64 years); (2) there was a slight female predominance; (3) 90% of the patients exhibited asymptomatic lymphadenopathy in the head and neck area; (4) only a minority of patients had B symptoms (6%) and poor performance status (8%); and (5) only 5% of patients were positive for M-protein. However, the 65 patients in this series exhibited relatively longer 5-year overall survival (85%) and failure-free survival (60%) than the NMZBL series published in western literature, suggesting that NMZBL should be classified as indolent lymphoma. Moreover, based on the histological findings, we further classified four histological subtypes as follows: (1) splenic type (n = 7); (2) floral type (n = 9); (3) mucosa-associated lymphoid tissue (MALT) type (n = 29); and (4) diffuse large B-cell lymphoma (DLBCL) + MALT type (n = 20). DLBCL + MALT type exhibited significantly poorer 5-year overall survival than the splenic variant. The recognition of DLBCL + MALT type appears important. No API2-MALT1 fusion transcript was detected in any of the 14 cases examined.