Peripheral blood smear demonstrating scattered small lymphoid cells with scant basophilic cytoplasm, consistent with circulating lymphoma cells.

The clinical image of the spleen depicts the intact spleen with serial sectioning that reveals the surface diffusely involved by numerous tan nodules measuring less than .1 cm up to .3 cm involving the entire splenic parenchyma.

The touch preparations of the spleen show small lymphoid cells with clumped nuclear chromatin, scant to moderate light blue cytoplasm, and scattered histiocytes (indicated by the arrows in the image on the left). 

In the higer power image (on the right) there is also a mitosis visible. 

Whole slide scanned image (pictured on the upper left) demonstrating multiple nodules throughout the splenic parenchyma.

At medium power (pictured on the upper right), the nodules comprise markedly expanded white pulp areas.

At higher power (pictured on the lower left) at the interface of the white pulp and red pulp, the nodular areas of the white pulp comprised monotonous small lymphoid cells with monocytoid cytomorphology. Note that the red pulp at the bottom is relatively uninvolved.

The lymphoma nodules are strongly positive for CD20, confirming B-cell origin. Also, on CD20, increased numbers of lymphoma cells infiltrating the red pulp are also noted.

The lymphoma cells (pictured on the left) are negative for CD5.

The lymphoma cells (pictured on the right) are also negative for CD10.

The lymphoma cells are negative for CD43 (pictured on the left) with variable weak BCL-2 expression (pictured on the right). However both CD43 and BCL-2 highlight background T cells.

The lymphoma cells are positive for IgD (pictured on the left). Most marginal zone lymphoma of splenic origin (as compared to nodal marginal zone lymphoma) are more likely to be positive for IgD.

CD21 immunostain (pictured on the right) highlights markedly expanded and tight follicular dendritic cell meshworks within the lymphoma nodules.