Clinical context

89 year old man referred by GP having been lost to followup under haematology. He is currently clinically stable reporting only mild fatigue.

At a glance

Age	89 Years
Sex	Male
Hb	83
WBC	63.6
MCV	90.3
Neutrophils	6.1
Lymphocytes	54.7
Platelets	233
Stain	MGG

About Low Grade B NHL

The morphology here shows several noteworthy features. The red cells show significant rouleaux, a morphological finding where the red cells appear to stack over each other. This is caused by antibody bound to the red cells attrating to or binding to each other.The patient is anaemic, although it can be hard to estimate the Hb from a blood film - doubly so when there is rouleaux. In this case, the sample also needs to be warmed to exclude cold haem-agglutination disease (CHAD) which can co-exist with B cell or plasma cell neoplasms. Platelet morphology is normal.

There are numerous smear cells, which are lymphocytes which have lysed upon the spreading of the blood film. Although some texts describe these as suggestive of CLL, they are often found in other lymphocytic pathologies. The striking feature is the raised lymphocyte count. The lymphocytes are small, mature and morphologically unremarkable. They are significantly increased in number but morphologically you cannot distinguish between B NHL, normal lymphocytes and CLL very easily. Flow cytometry is absolutely essential here.

The other white cells appear normal

This is another common malignancy in older patients, although in this case it is a low grade one. Low grade B cell malignancies include CLL, SLL, some variants of Mantle Cell Lymphoma and the diagnosis here - low grade B NHL. This is a catch all diagnosis when the morphology, molecular or imunophenotype don't match another diagnosis but there is a distinctly abnormal clonal lymphocyte population.

The naming in this case says everything we need to know - a low grade malignancy in a well older patient doesn't really need treatment. Here though, we see that the patient is significantly anaemic and therefore we might consider intervening.

Morphological features

Normal Neutrophil

This neutrophil shows normal morphology and they are normal in number suggesting that residual myelopoiesis is probably unaffected.

Rouleaux

Rouleaux is how we describe the appearance of stacked red cells. Red cells should float freely, touching only when the film is thick enough and not overlapping. When you can see clear stacking or overlapping red cells in a section where the film isn't thick enough for the cells to be touching this is rouleaux. In some cases, rouleaux can be so strong that you can't find any part of the film where the red cells are not stacked - even at the tail.\n\nRouleaux is strongly associated with the presence of high levels of paraprotein, and in particular IgM paraproteins. This is therefore suggestive of an underlying LPD or plasma cell disorder.

Normal Eosinophil

This is a normal eosinophil. Most eosinophils will have two lobes, but a significant proportion will have a third (usually smaller) middle lobe. Trilobed eosinophils can be seen in excess in Acute Lymphoblastic Leukaemia in children.

Excess Lymphoid Cells

This field shows excess lymphoid cells. It is not possible to tell the difference between low grade/normal B and T lymphocytes on morphology alone. In some T LPDs there are features such as cytoplasmic blebbing but normal or low grade malignant lymphocytes don't normally express these features.\n\nIt's important to look at lymphocytes in the correct part of the film - too thin and they will appear larger with more copious cytoplasm (and are easy to mistake for blasts), too thick and the lymphocytes will all appear small and unremarkable.\n\nIn this field you can see that the lymphocytes are small, mature but have slightly more cytoplasm than a completely normal mature lymphocyte. Some cells are slightly larger than others. \n\nThe number of lymphocytes should push you to suggest LPD (there are no reactive features), and the slightly larger size with excess cytoplasm should push you against CLL.

Normal Monocyte

Monocytes are rarely affected in low grade haematological malignancies. They are reduced significantly in hairy cell leukaemia, and increased in response to reactive/infective complications.\n\nThis monocyte is normal in morphology. They are normal in number throughout the film/

Smear Cell

This is a smear cell. It is a lymphocyte which has popped during the spreading of the film. Some texts will say these are associated with CLL in particular - and you can definitely see these in high number in CLL patients - but they are found in all B cell malignancies. You'll find some smear cells in completely normal patients.\n\nReport their presence, but don't let occasional smear cells affect your final diagnosis.

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