Mature B cell disorders
Mature lymphoproliferative disorders
Chronic lymphocytic leukaemia (CLL)
The most common lymphoproliferative disorder. The number of abnormal cells varies from low to very high. Cells are medium sized with mature chromatin. There are some characteristic features of chromatin, nuclear shape, or cytoplasm, but appearances may be variable.
Mantle cell lymphoma (MCL)
A relatively infrequent lymphoproliferative disorder. The number of abnormal cells varies from low to high. Cells are medium sized often with mixed mature and less mature forms circulating. Chromatin pattern, nuclear shape (complex or indented) may be typical, but appearances are often variable.
B-prolymphocytic leukaemia (PLL)
An uncommon lymphoproliferative disorder. The number of abnormal cells may be very high. Cells are medium to large sized with mature chromatin but a prominent nucleolus. Cytoplasm is often basophilic.
Follicular lymphoma (FL)
Not frequently seen, but has characteristic morphological features. Abnormal cells may be infrequent, and abnormal cell counts are rarely high Cells are typically very small with mature chromatin. Nuclei are typically clefted.
Plasma cell leukaemia (PCL)
The number of abnormal circulating cells varies and is occasionally high. Cellular appearance can vary greatly, but blue cytoplasm and offset nucleus is typical. Appearances may be may be atypical, but generally some of the cells will have a recognisable plasma cell morphology. A paraprotein is often present - look for rouleaux.
Lymphoplasmacytoid lymphoma (LPL)
The number of abnormal circulating cells tends to be low, sometimes with mixed appearance. A variable number of the cells may resemble plasma cells with blue cytoplasm and offset nucleus. Other cells may resemble normal mature cells. A paraprotein is often present - look for rouleaux.
Hairy cell leukaemia (HCL) and Hairy cell leukaemia variant (HCL-V)
The number of abnormal circulating cells tends to be low in most HCL but higher in HCL-V. The most distinctive feature is the hairy projections in each disorder. Nuclear shape, chromatin pattern and cytoplasmic colour all contribute to diagnosis. Monocytopenia is typical of HCL (but not HCL-V).
Marginal zone lymphomas
A mixed group of disorders, circulating cells are most frequently encountered in the splenic marginal zone lymphoma form. The most distinctive feature is a significant increase in cytoplasm compared with normal lymphocytes. Nuclear chromatin pattern tends to be bland without indentation and lacking a nucleolus. Cytoplasmic projections may be present, in some cases these are bi-polar.