Table 1.
Reagents and Conditions Used for Immunohistochemistry.
Table 2.
Summary of Clinical and Histologic Findings.
Fig 1.
Morphology of isolated atypical follicles.
An axillary lymph node dissection in a 61 year-old woman with breast carcinoma (case 1) shows one lymph node with scattered follicles containing sheets of centroblasts (A). The involved follicles exhibit sheets of large atypical cells with highly pleomorphic nuclear outlines and atypical mitoses (B). An axillary lymph node from a 53-year old woman (case 2) shows highly atypical large cells occupying an involved follicle (C). Sections of tonsil in a 6-year old boy (case 5) demonstrate a background of reactive follicular hyperplasia within which isolated follicles (upper left) show sheets of centroblasts (E and F).
Fig 2.
Immunohistochemistry of isolated atypical follicles.
An axillary lymph node dissection in a 58 year-old woman with breast carcinoma (case 3) shows a lymph node with a cluster of follicles (A). BCL2 expression is absent in both the involved and uninvolved follicles (B) and the involved follicle shows diminished CD10 expression relative to the surrounding normal germinal centers (C). CD23 demonstrates an intact follicular dendritic network around the involved follicle (D). Ki-67 is polarized in surrounding reactive follicles, but is not polarized in the involved follicles (E). The involved follicle in case 1 shows lambda light chain-restricted B-cells (F and G). Case 2 shows highly atypical large cells that by situ hybridization (ISH) for immunoglobulin kappa and lambda light chains show kappa-specific RNA in the majority of the atypical cells, confirming light chain restriction in the involved follicle (H and I). A periaortic lymph node from a 53-year old woman (case 4) shows abnormal strong IgM protein expression in the centroblasts of an involved follicle whereas the uninvolved follicle shows a weak dendritic pattern of IgM reactivity, which is typically seen in normal follicles (J).
Fig 3.
Atypical expression of HGAL in isolated atypical follicles.
An axillary lymph node in a 53-year old woman (case 2) shows a single atypical follicle with pleomorphic large cells overexpressing HGAL (A and B). Sections of the tonsil in a 6-year old boy stained with HGAL, show preservation of overall architecture with numerous normal reactive follicles and a gradient of HGAL staining with higher intensity in the dark zone. In the atypical follicle (indicated by arrow in panel D), HGAL staining is abnormal and shows overexpression throughout the affected follicle (C and D).
Table 3.
Summary of Immunohistologic Findings.
Table 4.
Summary of FISH and Molecular Findings.