Distributions of major sub-types of lymphoid malignancies among adults in Mashhad, Iran

Background: Global variations in the frequency of the major sub-types of lymphoma have been reported. However, studies on different sub-types of adult malignant lymphoma had never been conducted in Mashhad, Iran. In this paper, we aimed to identify the major sub-types of malignant lymphoma in our area and compare the distribution with other published studies. Methods: During a retrospective study we evaluate 391 adult patients with lymphoid malignancy from “Omid Hospital” – a cancer research center and an outpatient hematologic clinic in Mashhad – were evaluated from 2000 to 2009. Patients were reclassified using the World Health Organization (WHO) classification. Results: The frequency of non-Hodgkin lymphomas (NHL) was 92% (n = 359) and Hodgkin lymphoma (HL) was 8% (n = 32). The most frequent NHL sub-type using WHO classification was diffuse large B cell lymphoma (DLBCL) and the second most common NHL was chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). The most common sub-type of HL was mixed cellularity. In this study the frequency of primary extranodal NHL in our study was 11.5%, which slightly less common than other eastern countries. Conclusion: Our findings add to the body of knowledge concerning geographic variations in the descriptive epidemiology of the major lymphoma sub-types. Such observations are extremely important since they potentially point to underling etiological variations.