ABSTRACT
Primary extranodal lymphomas are common, and account for approximately 20–45% of all non-Hodgkin’s lymphomas. The presenting sites are diverse and many have unique clinical and pathological characteristics, and distinct biological behavior, thereby requiring a different management approach as compared with nodal lymphomas of similar histology. The primary extranodal lymphomas often present in a localized fashion and traditionally, have involved the use of some form of local therapy, either surgery or radiation therapy. There are specific anatomical, histological, and phenotypical patterns of disease that are consistently observed in the primary extranodal lymphomas. The investigations that revealed lymphoma-associated abnormalities during initial staging should be repeated after treatment to document response. The intensity of fluorine-18-fluoro-deoxyglucose uptake, as reflected in the standardized uptake values, for indolent lymphomas is generally lower than that of aggressive histology lymphomas, or relapsed disease. Diffuse large B-cell lymphomas arising in immunodeficient individuals also tend to involve extranodal organs such as the brain and the gastrointestinal tract.
