Interpretation of immunohistochemistry
| CD20 | CD79a | CD5 | CD10 | CD11c | CD23 | Cyclin D1 | Bcl2 | Bcl6 | TdT | Characteristic feature(s) | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| *No specific marker exists for distinguishing hairy cell leukaemia from other B cell leukaemias. Apart from CD11c, the expression of tartrate resistant acid phosphatase and CD103 (frozen material) are helpful, together with the characteristic morphological features. †Plasmacytomas are positive for CD138, which is a sensitive, although not specific, marker for plasma cells. ‡These include immune deficiency related lymphoproliferative disorders. However, these disorders may show decreased CD79a and/or CD20 expression, and may show prominent plasmacytic differentiation. §Burkitt’s lymphoma cannot always be distinguished from diffuse large B cell lymphoma based on the marker profile. The Ki-67 antibody can be helpful to determine whether all neoplastic cells are proliferating, supporting the diagnosis of Burkitt’s lymphoma. | |||||||||||
| CLL/SLL, chronic lymphocytic leukaemia/small lymphocytic leukaemia; MALT, mucosa associated lymphoid tissue; TdT, terminal deoxynucleotidyl transferase; +, positive as a rule; –, negative as a rule; +/–, usually positive, sometimes negative; –/+, usually negative, sometimes positive. | |||||||||||
| Predominantly small cell lymphomas | |||||||||||
| Precursor B lymphoblastic leukaemia | – | + | – | + | – | – | – | +/– | – | + | Monotonous appearance, finely dispersed chromatin pattern |
| CLL/SLL | + | + | + | – | – | + | – | + | – | – | Clumped chromatin, low mitotic rate |
| B cell prolymphocytic leukaemia | + | + | –/+ | – | – | – | – | + | – | – | High lymphocyte count (>100×109/l) |
| Lymphoplasmacytic lymphoma | + | + | – | – | – | – | – | + | – | – | Intranuclear inclusion (Dutcher) bodies, monoclonal IgM paraprotein |
| Splenic marginal zone lymphoma | + | + | – | – | – | – | – | + | – | – | Often presence of villous lymphocytes in the blood |
| Hairy cell leukaemia* | + | + | + | – | + | – | + | – | – | Increase of reticulin fibres in the bone marrow | |
| Plasma cell myeloma/extraosseous plasmacytoma† | +/– | + | – | – | – | – | –/+ | + | – | – | Monotypic cytoplasmic expression of either κ or λ immunoglobulin light chain |
| Nodal and extranodal marginal zone lymphoma | + | + | – | – | +/– | – | – | + | – | – | Perifollicular growth pattern. In MALT presence of lymphoepithelial lesions |
| Follicular lymphoma | + | + | – | + | – | – | – | + | + | – | Aggregates of CD21 positive follicular dendritic cells |
| Mantle cell lymphoma | + | + | + | – | – | – | + | + | – | – | Presence of epitheloid (pink) histiocytes |
| Predominantly large cell lymphomas | |||||||||||
| Diffuse large B cell lymphoma‡ | + | + | – | +/– | – | – | – | +/– | +/– | – | Nuclear size > normal macrophage nucleus |
| Burkitt’s lymphoma§ | + | + | – | + | – | – | – | – | + | – | Starry sky appearance, cohesive growth pattern |