Regional variation in the distribution of subtypes of lymphoid neoplasms in India.

Lymphoid malignancies (LM) are a heterogeneous group of tumours. The relative frequencies of the various types of LMs vary across geographic regions. The pattern in India shows significant differences from the rest of the world. As India is a vast country, we set out to investigate whether there are regional differences in the relative frequencies of the various LMs. A total of 562 LMs from three different regions in India--Barshi (western India, 102 cases), Pondicherry (southern India, 156 cases) and Jaipur (northern India, 304 cases) were analysed according to the WHO classification. The non-Hodgkin lymphoma (NHL) to Hodgkin disease (HD) ratio was 6.28 in Barshi, 1.26 in Pondicherry and 2.27 in Jaipur. The frequency of HD's various subtypes did not significantly differ among the three regions. While T-cell NHLs constituted only 12.5% of NHLs at Barshi, they accounted for 31 and 27.5% of all NHLs at Pondicherry and Jaipur, respectively. There were also notable differences in the specific subtypes of NHL between the three different geographic regions in India.