Follicular Lymphoma : Growth Pattern
Follicular lymphoma is a low-grade B-cell neoplasm composed of follicle center B-cells (centrocytes and centroblasts). It comprises approximately 40% of all adult non-Hodgkin lymphomas in the US. The most distinctive morphologic feature is nodular (follicular) pattern that attempts to recapitulate the architecture of a normal secondary lymphoid follicle. This low-power scan shows a lymph node with follicular lymphoma. The nodal architecture is completely effaced with obliteration of subcapsular and medullary sinuses. The neoplastic follicles of varying sizes, with a homogenous appearance and lacking mantle zones and tingible-body macrophages, are evenly distributed throughout the lymph node. In contrast, the hyperplastic follicles in a reactive lymph node are mainly cortical in distribution.