Follicular centre cell lymphoma with alpha heavy chain disease. A histopathological and immunohistological study.

The first recorded case of a small intestinal lymphoma with alpha heavy chain disease occurring in Hungary is reported. The clinical manifestation of the disease and the focal distribution of mucosal alterations do not fulfill the criteria to make a diagnosis of Mediterranean type lymphoma (MTL) but the lymphomatous segments of the jejunum show the same pathological and immunohistological characteristics as seen in MTL. One of the basic features of MTL, the so called lympho-histiocytic nodules, which have been suspected by previous authors to represent an incipient neoplastic process involving histiocytic cells, is identified as follicular centroblastic/centrocytic malignant lymphoma. The cytogenetical connection between the massive proliferation of abnormal alpha chain producing plasma cells and neoplastic germinal centres is substantiated by direct immunohistological evidence using a combined immunofluorescent and immunoperoxidase technique to detect heavy and light chains within the same cell. The sarcomatous-appearing pleomorphic cell proliferation is interpreted as an anaplastic change in the centroblastic/centrocytic lymphoma. Unequivocal evidence for an abnormal IgA production in this pleomorphic component has not been obtained. Our observations suggest that in alpha heavy chain disease the neoplastic cell population originates in the germinal centres.