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[The results of histological and immunohistological studies of primary biopsies in 400 patients with non-Hodgkin's lymphoma in the North-West region of Russia (according to WHO classification)].

AIM
To determine relative frequency of non-Hodgkin's lymphoma (NHL) variants according to WHO classification categories in the North-West of Russia by the data of the local pathomorphological department.


MATERIAL AND METHODS
Four hundred consecutive untreated patients with NHL were diagnosed according to the WHO classification between January 2000 and October 2003 in the Regional Bureau of Pathology, St-Petersburg. The patients' age, gender, location of the biopsied tumor focus were considered. The immunohistochemical study was performed by the paraffin section-immunoperoxidase method. Cases of plasma cell myeloma and bone marrow trephine biopsy diagnosed neoplasms were excluded, the rest series of 377 cases was compared to other regional world series.


RESULTS
B-cell lymphomas accounted for 79.6% and T-cell type for 20.4% of 377 NHL cases. 33.2% cases were different histological variants of diffuse large B-cell lymphoma, 17.0% were B-cell small lymphocytic lymphomas, 11.0%--follicular lymphomas, 4.5%--mantle cell lymphomas, 2.1%--extranodal marginal zone B-cell lymphomas (MALT-type), 1.9%--primary B-cell mediastinal lymphomas. Peripheral T-cell lymphomas, unspecified and anaplastic large T/null cell lymphomas were diagnosed in 6.4 and 4.2% of 377 cases, respectively. Other lymphoma diagnoses comprised 19.7%.


CONCLUSION
Diffuse large B-cell lymphomas and B-cell small lymphocytic lymphomas are prevalent among B-cell neoplasms. Follicular lymphomas and mantle cell lymphomas are less common in the North-West of Russia compared to Europe and USA. The relative frequency of extranodal marginal zone B-cell lymphomas (MALT-type) is lower and anaplastic large T/null cell lymphomas is higher than these in International Lymphoma Study Group, Taiwan and Japan series. This study provides evidence that the distribution pattern of non-Hodgkin's lymphoma subtypes in the North-West of Russia shows significant differences with those from the rest of the world.