Clinical context

69-year-old man with unexplained splenomegaly

At a glance

Stain	MGG

About Splenic Marginal Zone Lymphoma

Splenic marginal zone lymphoma (SMZL) typically presents as an indolent B-cell cancer with massive enlargement of the spleen (splenomegaly), moderate lymphocytosis, and bone marrow involvement, while swollen lymph nodes are rare. It is a disease of the older patient, with the median age of diagnosis around 65.

SMZL typically displays a mature B-cell immunophenotype that is positive for pan-B-cell markers (such as CD19, CD20, and CD22) and surface immunoglobulin (usually IgM, with or without IgD), while characteristically lacking markers like CD5, CD10, CD23, and CD103.

This blood film shows characteristic lymphocytes with SMZL morphology. There are hair like projections on the lymphocytes, which are typically coarser than those found in Hairy Cell leukaemia, and are in some cells polar, i.e. restricted to one axis of the cell. Not all cells will have polar cytoplasmic projections, and some will be normal looking lymphocytes.

This is a B cell malignancy, and as such we see abnormal antibody formation with results in rouleaux. Otherwise, as this is an indolent disease, the remainder of the morphology on the film is unexciting.

Morphological features

lymphocyte with polar villi

This blood film is a great example of lymphoid morphology. It's so heterogenous!. You might believe that in SMZL (also called Splenic Lymphoma with Villous Lymphocytes) that all lymphopcytes have polar projections, but thats not the case. This one does - the majority on this film have projections or blebs.

Abnormal Lymphocytes

This cluster of lymphocytes display a wide range of abnormal morphology - although they are clearly small and mature, they have cytoplasmic blebbing, hair like villi which are not necessarily polar. The number of cells, as well as the morphology, should push you away from hairy cell and into SMZL.

Rouleaux

The presence of rouleaux is consistent with a B cell LPD

Unexciting Red Cell Morphology

The patient may be a bit anaemic here - but overall the red cell morphology shows some EDTA change but not a lot else. There's no real red cell features which are noteworthy beyond rouleaux, so that in itself is worth commenting on.

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