Table of Contents
Marginal zone B-cell lymphoma – low magnification
LEGEND
No involvement of the epidermis, with presence of a Grenz zone (i.e., a thin spared area between the epidermis and dermis)
Marginal zone B-cell lymphoma – high magnification
LEGEND
In 30% of cases, reactive germinal centers are observed, composed of tingible body macrophages — macrophages that have phagocytosed apoptotic cells and contain cellular debris.
Dutcher bodies may sometimes be observed — intranuclear deposits of immunoglobulins in plasmacytoid cells, visible with PAS staining.
Nodular, diffuse, and sometimes peri-adnexal infiltrate of pale small lymphocytes (with clear halos, centrocyte-like, monomorphic), eosinophils, and plasma cells.
A reversed pattern is typically seen: a normal reactive germinal center surrounded by pale neoplastic marginal zone cells.
(This is the opposite of the normal architecture seen in a lymph node).
Marginal zone B-cell lymphoma – high magnification
LEGEND
The infiltrate is very rich in plasma cells.
Marginal zone B-cell lymphoma
CD138, a plasma cell marker, is positive.
Plasma cells are often located at the periphery of the infiltrate.
Marginal zone B-cell lymphoma
The neoplastic cells are CD20 and Bcl2 positive. Bcl6 is negative.
A reactive infiltrate of T lymphocytes, which are CD3 positive, is also frequently observed. Here is an example of reactive CD3+ expression.
Marginal zone B-cell lymphoma
Abnormal kappa/lambda light chain ratio
Here is an example of strong kappa expression.
