Changing trends in lymphoid neoplasm distribution in South Korea: analysis of 8615 cases from a single institute, 1997-2016: An observational study.

The purpose of this study was to evaluate changes in the proportion of lymphoid neoplasm subtypes in South Korea. A total of 8615 cases of lymphoid neoplasms diagnosed in 1997-2016 at Samsung Medical Center in South Korea were classified according to the 2008 World Health Organization system. The total number and proportion of lymphoid neoplasms were compared between these two decades, with data from nationwide studies, and with other countries.

Comparative studies of somatic and ongoing mutations in immunoglobulin heavy-chain variable region genes in diffuse large B-cell lymphomas of the stomach and the small intestine.

Context: Many diffuse large B-cell lymphomas (DLBCLs) of the stomach are believed to represent high-grade transformation of low-grade marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type, which is of memory B-cell origin, displaying evidence for positive antigen selection and a low level of ongoing somatic mutation of the rearranged immunoglobulin heavy-chain variable region (V(H)) genes. The pattern of somatic mutation has been studied little in intestinal DLBCLs.

Objective: To assess evidence for antigen selection and the levels of ongoing mutation, we analyzed the ratio of replacement to silent mutations, as well as the frequency of intraclonal sequence variation in gastric and small intestinal DLBCLs that showed no concomitant low-grade component.

Detection of germinal center B-cell lymphoma in archival specimens: critical evaluation of Bcl-6 protein expression in diffuse large B-cell lymphoma of the tonsil.

Expression of Bcl-6 and CD10, markers for the tumor of the germinal center (GC) B-cell derivation, has been studied in primary diffuse large B-cell lymphomas (DLBCLs) of the lymph node, gastrointestinal tract, and mediastinum. In these studies, the coexpression rate of CD10 and Bcl-6 was relatively constant at 30% approximately 40%, but the frequency of Bcl-6+ tumors varied from 55% to 100%, raising doubts about the usefulness of Bcl-6 expression in identifying the tumor of GC B-cell derivation. Because the expression of Bcl-6 in tumors of non-GC B-cell origin has recently been reported, we critically evaluated the expression of Bcl-6 and CD10 in primary DLBCLs of the tonsil, a relatively common tumor in Japan and Korea.

Primary central nervous system lymphoma in Korea: comparison of B- and T-cell lymphomas.

The great majority of primary central nervous system lymphoma (PCNSL) is known to be of B-lineage, with T-cell PCNSL (T-PCNSL) accounting for <5%. We report an unusually high incidence of T-cell lymphoma among the PCNSLs originated in a large general-care hospital in the metropolitan Seoul area. PCNSLs (n = 42) accrued from April 1995 through June 2001 were reviewed for histologic and clinical features, and immunohistochemical staining was done for CD3, CD20, CD4, CD8, Bcl-6, and CD10.

Critical evaluation of Bcl-6 protein expression in diffuse large B-cell lymphoma of the stomach and small intestine.

Unlabelled: Diffuse large B-cell lymphoma (DLBCL) of the gastrointestinal tract is heterogeneous, including mucosa-associated lymphoid tissue (MALT) origin and non-MALT, and they are indistinguishable. MALT lymphoma is a tumor of a post-germinal center (GC) memory B-cell origin, which is negative for Bcl-6 protein expression in low-grade but may become positive in high-grade tumors. Because Bcl-6 expression patterns in lymphoma of GC and non-GC B-cell origins have recently been characterized and CD10 is generally regarded as a specific marker for GC B cells, we critically evaluated gastric and small intestinal DLBCLs to see whether it is possible to identify tumor of GC B-cell origin by immunostaining in archival specimens.

Clinicopathologic analysis of ocular adnexal lymphomas: extranodal marginal zone b-cell lymphoma constitutes the vast majority of ocular lymphomas among Koreans and affects younger patients.

The majority of ocular adnexal lymphomas (OAL) are primary marginal zone B-cell lymphomas (MALT lymphomas). The present study correlated the clinicopathological variables with the histologic subtypes by World Health Organization (WHO) classification with emphasis on MALT lymphomas in OALs of Koreans. There were 68 cases (31 males and 37 females), with a mean age of 45.

CD4+CD56+CD68+hematopoietic tumor of probable plasmacytoid monocyte derivation with weak expression of cytoplasmic CD3.

Hematopoietic neoplasm coexpressing CD4 and CD56 includes a subset of acute myeloid leukemia with myelomonocytic differentiation, plasmacytoid monocyte tumor, and other immature hematopoietic neoplasms of undefined origin. Herein, we report a CD4+CD56+CD68+ hematopoietic tumor that was thought to be a tumor of plasmacytoid monocytes. This case is unique in the absence of accompanying myelomonocytic leukemia and the faint expression of cCD3 on the tumor cells.

Focal follicular features in tonsillar diffuse large B-cell lymphomas: follicular lymphoma with diffuse areas or follicular colonization.

Focal follicular features in diffuse large B-cell lymphomas (DLBCLs) are bound to raise the question of follicular lymphoma (FL) with diffuse areas, because the diagnosis of FL is based on the presence of follicular areas, even though focal. We report 7 cases of primary tonsillar DLBCLs with focal follicular features that presented with morphologic, immunohistochemical, and biological features distinct from those of FL. Histologically, these tumors were characterized by involvement of pericryptal follicles with adjacent dominant diffuse areas.

CD10 expression in primary intestinal large B-cell lymphomas: its clinical significance.

Objective: To determine the prevalence and clinical significance of a follicular origin in primary intestinal large B-cell lymphomas.

Design: We performed immunohistochemistry for detection of CD10 and Bcl-6 in paraffin-embedded tissue sections from 32 patients who had surgically resected primary intestinal lymphomas. We then correlated the expression of CD10 protein with various clinical parameters.