Cleaved and multilobated cell immunocytoma of low grade malignancy with amyloid. An immunohistochemical and electron microscopical study.

An unusual variant of immunocytoma of low grade malignancy, cytologically resembling follicular cleaved-cell malignant lymphoma is described. Presence of heavy deposits of amyloid, intracytoplasmic monoclonal IgM-kappa immunoglobulin, cells with Dutcher inclusions, electron-microscopic features and negativity of T-cell markers led to diagnosis of immunocytoma. After cytostatic chemotherapy the lymphoma changed its morphology into typical lymphoplasmacytoid immunocytoma.