Walsh & Hoyt: Non-Hodgkin's Lymphomas

The non-Hodgkins lymphomas are generally considered together even though they differ considerably in their biologic behavior, with some having a rather indolent course and others being more aggressive. Different classifications emphasize the clinical, immunologic, or histopathologic features of these somewhat diverse neoplasms. Histological classifications emphasize the overall microscopic pattern of the tumor (follicular or nodular versus diffuse; differentiated versus undifferentiated), the size and shape of the primary tumor cell (small versus large; cleaved versus noncleaved; convoluted versus nonconvoluted), the immunologic type of the tumor cell (T versus B), and the level of malignancy of the tumor (low, intermediate, or high grade). Although none of these approaches is perfect, partly because there is a significant inter- as well as intra-observer variation in the classification of any given tumor, the Revised European-American Classification of Lymphoid Neoplasms (REAL) (1994) and the WHO classification of lymphomas (1999) are widely accepted. In this chapter, three main types of the non-Hodgkins lymphomas are discussed based on their neuro-ophthalmologic significance: diffuse large-cell lymphoma, Burkitts lymphoma, and other lymphocytic and lymphoblastic lymphomas, both diffuse and follicular.