Follicular Dendritic Cell Pattern in Early Lymphomas Involving Follicles

Abstract

This article reviews the most typical follicular dendritic cell (FDC) patterns displayed by early lymphomas involving follicles. In in situ follicular lymphoma, FDCs form a well-developed round (spherical) dendritic meshwork with a sharp outline. Other patterns that can be seen include contracted/distorted/disintegrated FDC meshworks. In early mantle cell lymphoma with mantle zone pattern, FDCs compose an ill-outlined and loosely arranged "centrifugal" meshwork. In marginal zone lymphoma, the FDC meshwork forms a relatively well-developed nodular meshwork with irregular outlines. In nodular lymphocyte predominant (LP) Hodgkin lymphoma, LP tumor cells are localized within an environment with prominent FDC meshwork and rare or absent LP cells outside the nodules. In angioimmunoblastic T-cell lymphoma (AITL), scattered regressed germinal centers are usually noted, although hyperplastic germinal centers are seen during the early stages of the disease (EAITL). Identifying the FDC meshwork, mainly in association with blood vessels, constitutes one of the most typical findings of the disease. In conclusion, the morphologic pattern of the FDC meshwork in early lymphomas of follicular origin is heterogenous and differs according to the lymphoma subtypes. These FDC patterns are recognizable in the most typical cases when the lymphoma is in its early stage and still maintains a follicular/nodular pattern of growth. The FDC patterns seen in the CD21 and CD23 stains contribute to the recognition of early stages of lymphomas involving follicles. Conversely, tumor cell immunostains for BCL2, cyclin D1, and other stains form the basis for the definition of lymphoma subtypes.

Expanded Circulating Follicular Dendritic Cells Facilitate Immune Responses in Chronic HBV Infection

“…A previous study has demonstrated that FDCs are closely associated with the residency and proliferation of tumor cells in follicle-derived lymphomas, even when the in ltration localizes in the bone marrow and non-lymphoid organs [28]. Moreover, another study has demonstrated that the precursors of FDCs are perivascular cells and can develop into mature FDCs under certain conditions [12], which indicates that FDCs may not restrict in the lymphatic organ.…”

Follicular dendritic cell in lymphomas of follicular origin

“…FDC's main functions comprise: histoarchitecture organization of lymphoid follicles, antigen trapping and presentation, organization of apoptotic "waste" removing, and self-immunity prevention. Organizing functions of FDCs are chemokine dependent (Carbone and Gloghini 2014). B-cell lymphomas of follicular origin: classification B-cell lymphomas of presumed follicular origin include follicular lymphoma (FL), mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL).…”

“…The FDC meshwork usually form a well-developed "spherical" dendritic meshwork with a sharp outline highlighting an attenuated mantle zone (Figure 1). Other patterns that can be seen include contracted/distorted/disintegrated FDC meshworks (Rezk et al, 2013;Carbone and Gloghini 2014).…”

“…When there is a nodular growth pattern with residual GCs, obviously the reactive GCs have preserved tight FDC meshworks, whereas neoplastic zones show a disrupted and fragmented FDC meshwork. Conversely, as the expansion of the neoplastic mantle zones continue outward, MCL neoplastic nodules with absent FDC meshworks and negative staining for CD21 and CD23 are formed (Carbone and Gloghini 2014).…”

“…Immunohistochemical studies show that in all MZL entities neoplastic B cells express CD20, CD43, and BCL2, but not CD3, CD5, CD10, and CD23 (Carbone et al 1986;Rezk et al, 2013). The FDC meshwork is variably distorted and disintegrated when there is a follicular colonization (Rez et al, 2013;Carbone and Gloghini, 2014;Cook et al, 2017;Campo et al, 2017). The presence of remnants of FDC meshwork suggests colonized follicles (Rez et al, 2013;Carbone and Gloghini, 2014).The FDC meshwork is more evident in cases with a nodular/follicular pattern (Figure 3).…”