Flow cytometry: Marginal Zone Lymphoma
From haematologyetc.co.uk
Typical MZL morphology, note the small/medium size, bland chromatin pattern in a slightly squared nucleus, and the tendency of cytoplasm to gently engage adjacent red cells
Background to flow cytometric diagnosis
A difficult diagnosis - flow cytometry can suggest a diagnosis, but the immunophenotype may overlap with related diagnoses including atypical cases of CLL and MCL. Generally it is correct to suggest the diagnosis, but recognise that the profile is not fully specific, and confirmation by other modalities may be required.
CD45 Expression
Side scatter of CLL cells is typically low, with a broad range and relatively weak expression of CD45 compared with normal lymphocytes. The CLL cells (highlighted in blue) therefore tend to the left of normal T cells (red) - giving the CLL population a rather elongated "slug-like" shape.'
Immunophenotype of MZL | |||
---|---|---|---|
Major markers useful in CLL diagnosis | |||
Marker | Freq | Level | Comment |
κ/λ | Expect moderate or strong restricted κ or λ expression | ||
FMC7 | - | FMC7 is frequently expressed by typical MCL | |
CD5 | - | Expression of CD5 is characteristic of MCL | |
CD10 | - | Infrequently expressed, expression may suggest FL | |
CD11C | Expressed in some cases of MCL but not typical | ||
CD19 | - | Expression is expected, typically more strongly than in CLL | |
CD20 | - | Expression is expected, typically stronger than CLL | |
CD23 | - | Typically not expressed by MCL, may rarely be expressed | |
CD25 | Not typical of MCL, not generally strong as HCL | ||
CD38 | - | Expression is expected in MCL but CD138 should be absent | |
CD43 | - | Lower expression than in CLL, may be helpful in some cases | |
CD79b | Expression is expected and should be stronger than CLL | ||
CD103 | - | Not expressed by MCL, consider HCL if found | |
CD138 | - | Predominantly expressed at plasma cell differentiation | |
CD200 | - | Characteristically (though not always) negative in MCL |
Key to table:
Markers most useful in initial diagnosis are underlined in blue text
Key to colour code for expression frequency Click for link
Key to expression strength code and use Click for link