Intermediate lymphocytic lymphoma: its frequency and characteristics in Japan.

The nature of intermediate lymphocytic lymphoma (ILL) in Japan was investigated. For this purpose, we have reviewed 1,766 cases of malignant lymphoma and related diseases, and 38 cases were selected as ILL. In two cases, small lymphoid cells proliferated as a wide mantle of atrophic secondary follicles. The frequency of ILL in nodal and extranodal non-Hodgkin's lymphoma was 3.4% and 3.9%, respectively. The frequency was high in orbit and salivary gland lymphomas; two out of three cases and one out of six cases, respectively. Age range (median) and sex ratio (M:F) in nodal and extranodal cases were 34-65 (52) years and 2.1:1 and 22-82 (61) years and 1.1:1, respectively. The majority of nodal ILL presented as systemic disease, but extranodal ILL usually presented as localized disease. ILL when treated with chemotherapy and/or radiotherapy had a favorable prognosis, the 5-year survival rate was 82%.