Distribution of various subtypes of non-Hodgkin's lymphoma in India: a study of 2773 lymphomas using R.E.A.L. and WHO Classifications.

INTRODUCTION

The distribution of the major subtypes of non-Hodgkin's lymphoma (NHL) differs across geographic regions. This is the first study from India that has incorporated immunophenotypic findings while investigating the distribution of NHL subtypes.

PATIENTS AND

METHODS

All cases diagnosed as NHL between January 1995 and June 1998 in the Department of Pathology and in the Lymphoma Registry, Tata Memorial Hospital, Bombay, were selected for the study. The cases were reviewed by three pathologists and diagnostic problems were discussed by a panel of pathologists with a special interest in lymph node pathology. Of a total of 2831 cases, the diagnosis of NHL was accepted in 2773 cases.

RESULTS

B-cell lymphomas formed 79.1% of the NHLs, whereas T-cell lymphomas formed 16.2% of the total. Diffuse large B-cell lymphoma was the most common subtype (34% of all NHLs). Follicular centre-cell lymphomas, B-cell small lymphocytic lymphoma, mantle-cell lymphoma, and marginal zone B-cell lymphomas (including MALT lymphomas) amounted to 12.6%, 5.7%, 3.4%, and 8.2%, respectively. Among the T-cell lymphomas, T-cell lymphoblastic lymphoma, anaplastic large-cell lymphomas of T/null-cell type, and other nodal peripheral T-cell lymphomas accounted for 6%, 4.3%, and 2.9% of all cases, respectively.

CONCLUSIONS

The distribution of NHL subtypes in India shows important differences with those from the rest of the world. Follicular lymphoma and mantle-cell lymphoma are less common in India compared to Europe and the USA. Peripheral T-cell lymphomas and T/NK-cell lymphomas of nasal and nasal types, which are common in many other Asian countries, are also less prevalent. T-cell lymphoblastic lymphoma and anaplastic large T/null cell lymphoma are more prevalent in India.