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 may be expressed in MZL and may be strong | |
| CD5 | - | Expression of CD5 is uncommon in MZL | |
| CD10 | - | Infrequently expressed, expression may suggest FL | |
| CD11C | Frequently expressed in MZL and should be looked for | ||
| CD19 | - | Expression is expected, typically more strongly than in CLL | |
| CD20 | - | Expression is expected, typically stronger than CLL | |
| CD23 | - | Typically not expressed by MZL, may rarely be expressed | |
| CD25 | May be expressed by MZL, not generally strong as HCL | ||
| CD38 | - | Expression is expected in MZL 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 expected in MZL, consider HCL if found | |
| CD138 | - | Expression may occur in MZL | |
| CD200 | - | Characteristically (though not always) negative in MZL | |
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