Mantle zone lymphoma. A clinicopathologic study of 22 cases.

A clinicopathologic analysis of 22 cases of mantle zone lymphoma (MZL) was performed. In lymph node sections, MZL was characterized by the proliferation of neoplastic small lymphoid cells in wide mantles around benign germinal centers. Eighteen cases were of the intermediate lymphocytic type and four cases were of the small lymphocytic type. Immunohistologic analysis of paraffin sections revealed the following characteristic immunophenotype of MZL: L26, LN2, NUB1 and T2/48 positive, and LN5, LN1, AF6 and UCHL1 negative. The immunophenotype of MZL was identical to that of normal primary lymphoid follicles and the mantle zones of secondary follicles, except for the absence of staining with LN5 in MZL. The median age of the patients was 63 years, and the male-to-female ratio was 1.2:1. B symptoms were present in 55% of the patients, and 81% had splenomegaly. An absolute lymphocytosis was present at the time of initial diagnosis in 13% of the patients, and 67% had bone marrow involvement by lymphoma. Thirteen percent of the patients had Stage II disease, 23% had Stage III disease, and 64% had Stage IV disease. All 22 patients received some form of therapy, with 73% receiving multiagent chemotherapy. Eleven patients achieved a complete remission at some time during their course. The overall median survival of the entire group was 88 months. Clinical features which appeared to influence survival adversely included an absolute lymphocyte count above 4000/microliters, a platelet count less than 100,000/microliters, and male sex. Achievement of a complete remission at any time favorably influenced survival. Pathologic features which appeared to influence survival adversely were a mitotic rate of 10 or more per 10 high-power fields (HPF) and the presence of 40 or more large lymphoid cells per 10 HPF. These findings lead the authors to conclude that MZL is a distinctive form of low-grade non-Hodgkin's lymphoma.