An unusual lymphoid lesion mimicking meningioma

Magnetic resonance imaging shows an en plaque mass lesion with homogenous enhancement (A). Hematoxylin and eosin (HE) staining shows dura matter with multiple lymphoid follicular structures; large interfollicular areas are also seen. Germinal center with polymorphic lymphoid blast cells as well as a sharply demarcated mantle zone with small lymphocytic cells could be clearly distinguished (B). Reactive activated B cells (centroblasts), centocytes and tingible body macrophages are seen in the germinal center, HE staining (C). Germinal center revealed predominance of the B-cells, CD20-Staining (D). CD3-staining shows multiple T lymphocytes in the mantle zone (E). Bcl-2 positive B cells are seen exclusively in the mantle zone of the follicle. Scale bar 100 µm (F).