Prognostic significance of parafollicular small lymphocytes in follicular lymphoma: clinicopathological studies of 82 cases of primary nodal origin.

Pretreatment biopsy material of 82 cases of follicular lymphoma of lymph node origin was reviewed. According to the amount of small lymphocytes in the parafollicular lymphoid tissue (PSL), tumors were classified: PSL++, abundant lymphocytes with prominent postcapillary venules; PSL+, a number of lymphocytes readily recognizable, postcapillary venules present but not prominent; PSL+/-, lymphocytes barely appreciable or absent. Five-year actuarial survival rates were 82.7% in PSL++, 42.3% in PSL+, and 0% in PSL+/-. Ten-year actuarial survival rates were 51.5% and 4.7% in PSL++ and +, respectively. The PSL++ pattern was often associated with localized disease. Patients surviving more than 5 years with disseminated disease had either PSL++ or +. Survival was better correlated with PSL patterns than histologic tumor types or clinical stages. Transition of the pattern from nodular to diffuse occurred in 17 of 26 cases observed and was concomitant with the progressive loss of parafollicular (or interfollicular) components, namely small lymphocytes and lymphocyte-associated vasculature. Classification of follicular lymphoma based on parafollicular small lymphocytes (PSL) offers a new set of prognostic criteria and a guide to improved clinical management.