#00061554

This image depicts an immunohistochemical stain for CD10 from excisional biopsy of a lymph node. Clusters of B cells confined to the germinal centers, most prominently towards the periphery of each follicle, are strongly positive for CD10. In the context of relatively intact nodal architecture, well-preserved mantle cuffs with sharp edges to the germinal center, and no evidence of interfollicular infiltration, this staining pattern is most consistent with in situ follicular neoplasia (ISFN). These CD10+ B cells also demonstrated strong BCL-2 expression. However, the extent of involvement and number of follicles involved are too few for an outright diagnosis of partial follicular lymphoma. Follicular dendritic cells are considered to represent the barrier that contains the neoplastic B cells to the follicles.