The clinicopathological analysis of 303 cases with malignant lymphoma classified according to the World Health Organization classification system in a single institute of Taiwan

Abstract

Several reports have shown a different distribution of malignant lymphoma (ML) in Asian and Western populations. The purpose of our survey was to elucidate whether there are substantial differences in the frequencies of subtypes of ML between different geographical areas. All entities diagnosed as ML between June 1995 and December 2007 were selected according to the 2008 World Health Organization (WHO) classification and searched for clinical outcomes. The cases were retrieved and reviewed by a panel of clinical haematologists and haematopathologists. A total of 303 patients with ML were identified for retrospective analysis. Of the 303 patients with ML, 278 patients (91.7%) had non-Hodgkin's lymphoma (NHL), and 25 (9.2%) had Hodgkin's lymphoma. Of the 278 patients with NHL, 223 (73.6%) had lymphoma of B-cell lineage, and 55 (18.1%) had lymphoma of T-cell lineage. One hundred and thirty-seven patients were diagnosed with diffuse large B-cell lymphoma, which was the most common B-cell lineage subtype and accounted for 45.2% of patients with NHL. Peripheral T-cell lymphomas were the most frequent subset of the T-cell neoplasms, comprising 10.6% of ML. Extranodal involvement was found in 125 (44.9%) of the 278 patients with NHL, and the lymph node was the site of primary involvement in 153 patients (55.1%). Fifty-nine (47.2%) of the 125 patients with extranodal presentation had gastrointestinal tract involvement. Outcome was worse in patients with extranodal NHL than in those with nodal NHL through the entire follow-up period; the difference in survival rates was significant. Our findings clarify the applicability and prognostic relevance of the WHO classification system and provide further information about the incidence of various lymphoma subtypes in Taiwan. Primary extranodal NHL was associated with a worse prognosis and distinct characteristics compared with nodal NHL. The outcome of different types of extranodal NHL should be investigated further.