PMC4249607_01
H & E and immunohistochemical staining of follicular components. Hematoxylin and eosin stained sections showed numerous neoplastic follicles occupying almost the entire lymph node, effacing the normal nodal architecture extending from the cortex to the hilum, and invading beyond the capsule ((a) 4x). The neoplastic follicles consist of small centrocytes with ovoid shape, small angulated nuclei, clumped chromatin, and inconspicuous or absent nucleoli. Rare intermixed centroblasts are seen ((b) 20x and (c) 40 xs). Immunohistochemical staining revealed the germinal center cells expressing the pan B-cell marker CD20 ((d) 10x) in addition to germinal center-associated markers CD10 ((e) 10x), BCL-6 ((f) 10x), and BCL-2 ((g) 10x). The collective histologic and immunophenotype findings indicated a follicular lymphoma, grade 1 of 3.
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fig1
He, therefore, underwent excisional biopsy of a mesenteric lymph node visible on the CT scan (Figure 1).
Immunohistochemical staining of in situ mantle cell lymphoma components. Cyclin D1 immunohistochemistry revealed a peripheral rim of positive cells within the mantle zones of the majority of the neoplastic secondary follicles ((a) 4x and (b) 20x). These cells appeared to show dim coexpression of CD5 ((c) 20x).
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fig2
However, CCND1 unexpectedly highlighted CD5 positive mantle zone cells in neoplastic follicles, which suggested a MCLIS (Figure 2) component.