Chronic lymphocytic leukaemia – classic morphology

Bone marrow smear shows a uniform population of lymphocytes and a few basket cells (green arrows). Monoclonal gammopathy can occur in some cases of CLL; this can manifest itself as the rouleaux formation of erythrocytes (red arrows).

Tumour cells in CLL are mature lymphocytes that are slightly larger than normal lymphocytes, have clumped chromatin and scanty basophilic cytoplasm. The blocs of chromatin are separated from each other by light border lines. Some cells, such as the intermediate erythroid precursor (green arrow), do not belong to the neoplastic infiltration.

This is another example of bone marrow aspiration smear in a classic variant of CLL. All cells shown in the image are neoplastic elements; smudge cells or basket cell (also called Gumprecht shadows) are also present (green arrows).

A: Relative lymphocytosis in peripheral blood, > 85% of lymphocytes. The cell population expressed a high intensity of CD45 and a low intensity of SS.

B: Population of CLL cells, > 85% of lymphocytes. There is a high expression of CD19 and CD5 (purple).

C, D: Characteristic CD23 and CD200 positivity and CD79b negativity or low expression of CLL cells.