The World Health Organization classification of malignant lymphomas in Japan: Incidence of recently recognized entities

Abstract

New insights into the immunology and genetics of malignant lymphomas have allowed the recognition of new entities and the refinement of previously recognized disease categories. The relative incidence of these subtypes of malignant lymphoma is also known to differ according to geographic location. In order to clarify the current status of malignant lymphomas in Japan and the relative incidences of their subtypes, 3194 patients were classified according to the new World Health Organization (WHO) classification. Among these were 3025 cases (94.71%) of non‐Hodgkin's lymphoma (2189 cases (68.53%) of B‐cell lymphoma, 796 cases (24.92%) of T‐cell lymphoma) and 141 cases (4.41%) of Hodgkin's lymphoma. The incidences of the major subtypes of non‐Hodgkin's lymphoma were 33.34% for diffuse large B‐cell lymphoma, 8.45% for marginal zone B‐cell lymphoma of mucosa‐associated lymphoid tissue (MALT) type, 8.05% for plasma cell myeloma, 7.45% for adult T‐cell leukemia/lymphoma (ATLL), 6.7% for follicular lymphoma, 6.67% for peripheral T‐cell lymphoma of unspecified type, 2.79% for mantle cell lymphoma, 2.6% for nasal and nasal‐type T/NK cell lymphoma, 2.35% for angioimmunoblastic T‐cell lymphoma, and 2.35% for precursor B‐cell lymphoblastic leukemia/lymphoma, in decreasing order. The other subtypes comprised less than 2%, mainly precursor T‐cell lymphoblastic lymphoma/leukemia (1.72%), anaplastic large‐cell lymphoma of T‐ and null‐cell types (1.53%), and B‐cell chronic lymphocytic leukemia/small lymphocytic lymphoma (1.31%). The incidence of ATLL was influenced by its high percentage (19.20%) in the south‐western Japanese island, Kyushu, an endemic area of human T‐cell leukemia virus type 1 (HTLV‐1), but which appeared to be lower than that in a previous study. The nodular sclerosis and mixed cellularity types of Hodgkin's disease occupied 1.78% and 1.63%, respectively. These data are distinct from those in Western countries and similar in several ways to those in the East, although the relatively high rate of ATLL was attributed to the geographical difference in the etiologic factor, HTLV‐1.

Epidemiology of Lymphoid Malignancy in Asia

“…In a previous study in Japan the incidence rate of FL was 6.7% (Pathologists, 2000), but in a recent study in Japan they found a relatively high rate of FL (19%) similar to that of western countries (11-30%) (Aoki, et al, 2008). They suggest the following reasons for the relatively high rate of occurrence of follicular lymphomas.…”

“…In an Indian study T-cell lymphomas formed 16.2% of the total NHL (Naresh, Srinivas, & Soman, 2000). Previous Japanese studies have reported a higher proportion of Tcell lymphoma, accounting for approximately 32-38% of non-Hodgkin lymphoma (Kadin, Berard, Nanba, & Wakasa, 1983;Pathologists, 2000), but the recent findings in Japan show the decreased frequency of T/NK cell lineage (25%) (Aoki, et al, 2008). In endemic area for HTLV1 in Japan, T/NK-cell neoplasm accounted for a higher percentage of lymphoid neoplasm, in Kyushu (30%) and Okinawa (38%), compared with other areas of Japan (18-20%) (Aoki, et al, 2008).…”

The Significance of Bone Marrow Involvement in Aggressive Lymphomas: A Retrospective Comparison of Clinical Outcomes between Peripheral T Cell Lymphoma and Diffuse Large B Cell Lymphoma in China

“…PTCLs are a heterogeneous group of neoplasms accounting for 7–10% of NHL in the Western countries compared to 20–30% of NHL in East Asia, including China [5,11,12,13]. Patients often present with an advanced stage of the disease, and the neoplasms are characterized by widespread dissemination and aggressive behavior.…”

“…Few studies have directly compared advanced stage DLBCL with PTCL, which is probably attributable to the rarity of PTCL as it accounts for only approximately 10% of all non-Hodgkin’s lymphomas (NHL) encountered in the Western countries [5,11] and about 25% of those in Asia [12,13]. Patients with PTCL with BMI were even fewer, i.e.…”

A rare case of anasarca caused by infiltration of the pituitary gland by diffuse large B-cell lymphoma

“…Diffuse large B-cell lymphoma (DLBCL) reveals extranodal involvements in more than 30% of patients at diagnosis [2,3]. The gastrointestinal tract, bone marrow, pancreas, liver, intravascular system, or brain is involved in patients with DLBCL.…”