MSH: A group of heterogeneous lymphoid tumors generally expressing one or more B-cell antigens or representing malignant transformations of B-lymphocytes.,CSP: any in a large group of nonHodgkin's lymphoma's characterized by malignant transformation of the B lymphocytes.,NCI: The most common type of non-Hodgkin lymphoma. It includes the most frequently seen morphologic variants which are: diffuse large B-cell lymphoma, follicular lymphoma, small lymphocytic lymphoma and marginal zone B-cell lymphoma. -- 2003,NCI: A type of cancer that forms in B cells (a type of immune system cell). B-cell lymphomas usually occur in adults and may be either indolent (slow-growing) or aggressive (fast-growing). There are many different types of B-cell lymphomas, and prognosis and treatment depend on the type and stage of cancer.