b cell lymphoma prognosis | B lymphomas Tumors of B-cell precursors

B lymphomas
Tumors of B-cell precursors




Tumours of B-cell precursors may be in the form of acute lymphoblastic leukemia with bone marrow infiltration and leukemia blood formula, but also in the form of a lymphadenopathy, skin or bone infiltration Without infiltration of the marrow. This latest clinical presentation is often found in children and can be followed by leukemia release with late infiltration of the marrow. Tumor cells express B-cell markers such as CD 19, CD22, and CD79a. The CD20 and CD10 (CALLA) antigens are often as positive; CD10 is a favorable prognosis factor in children. When tumor cells express Ig on the surface, the prognosis is particularly bad. Translocations between chromosomes 1 and 19 or 9 and 22, or mutations within chromosome 1 Iq also indicate a very adverse prognosis.

B Peripheral Lymphomas
This group of lymphomas represents two thirds of the LMNH.

1. lymphomas such as chronic lymphocytic leukemia (LLC-B) or prolymphocylaire leukemia (b-LPL) reach older individuals and are characterized by very high leukocytosis and strong infiltration of the marrow. Lymph nodes, spleen and liver can also be achieved. The tumor cells of the LLC-B appear as small lymphocytes at the round nucleus. The B-LPL cells are larger and have a prominent central nucleolus. B-LPL is characterized by significant splenomegaly and aggressive clinical development, while the LLC-B shows a slow and relatively benign evolution.

In addition to the classic B markers CD 19, CD20 and CD22, the cells of an LLC-B express typically CD23 and the marker T CD5; The expression of the surface Ig is low. The diagnosis of the LLC-B is done by a blood smear or by a phenotypic study at the cytometer of flux. At the histological analysis of the ganglion, the disease is considered to be lymphocytic lymphoma. A deletion within chromosome 13 or a syndrome 12 is found in 30 p. 100 of the cases.

2. Lymphoplasmocytaire lymphoma, or lymphoplasmocytoid, is characterized by small lymphoid cells that differ in plasma. The majority of cases correspond to Waldenstrom's disease; A monoclonal IgM-type protein is often found. Tumor cells present themselves either as small lymphocytes with a wide and basophile cytoplasm, or as plasma. cytoplasmic IG (CYT-ig) of IgM type is characteristic. We mention the deletions of chromosomes 11, 13 and 17 among genetic alterations.

3. Mantle lymphoma largely corresponds to the Centrocytaire lymphoma of the Kiel classification: The malignant cells are small or medium in size with a notched core and large nucleoli. The cells express surface Ig and CD5 antigen. A translocation between chromosomes 11 and 14 leads to a hyper-expression of the cyclin D! , a protein involved in the cell cycle. The disease mostly reaches older men and is generally disseminated during the diagnosis. The average survival is 3 to 5 years.

4. Germ centre lymphomas represent a quarter of the LMNH and develop from the B cells of the germ centers, centrocytes, and centroblasts. The disease reaches both men and women. Histology regains dominance of centrocytes. A diffuse attack indicates an adverse prognosis. Tumor cells express Ig and CD1O + on the cell surface. Translocation (14; 18) induced activation of the BCL-2 antiapoptotique gene, responsible for the survival of Centrocytes.

5. Among the lymphomas of the marginal Wne, a nodal and extranodal type are distinguished. The nodal type is derived from B cells of the lymphoid tissue associated with the mucous membranes (MALT) and represents 50 p. 100 of the stomach lymphomas, about 40 p. 100 of the orbital cavity lymphomas as well as the majority of the lymphomas of the lungs and thyroid glands and Salivary. Stomach lymphomas are generally associated with Helicobacter pylori infection, which is responsible for the stimulation and proliferation of mucosal lymphocytes. Antibacterial therapy can induce a remission of lymphoma. The lymphoma of the marginal Wne nodal is derived from monocytoïdes B cells of ganglion marginal areas; The incidence is increased in Sjdgren syndrome. The evolution is relatively benign. The immunological phenotype of the cells resembles that of the Extranodal type.

6. The lymphoma of the marginal wne of the spleen is derived from small cells B Nui memory would undergo a transformation in the spleen following their differentiation in the germ centers. The bone marrow is infiltrated. Tumor cells circulate in the blood in the form of urban lymphocytes. The clinical progression is very slow. A splenectomy can induce long-term remissions.

7. Hairy leukemia is characterized by cells with a hair cytoplasm and an oval nucleus. The disease is manifested by a splenomegaly and a pancytopenia. The bone marrow shows significant fibrosis but the lymph nodes are rarely reached. B cells express high-density surface Ig and CD22. The expression of the CD103 antigen is typical. Therapy with analogues of purine bases or interferon is very effective.

The CLEAR classification includes plasmacytoma or multiple myeloma (see p. 133) in B lymphomas; Indeed, this disease may initially present itself as a solid tumor of a lymphatic tissue.

9. Large-cell diffuse lymphomas are relatively common (about 30 p. 100 of LMNH) and also reach children. They are derived from peripheral B cells at different stages of differentiation. These lymphomas are very aggressive but can in principle be cured by aggressive chemotherapy. Extra-ganglion events are common; They concern the stomach, the central nervous system, the bones, the kidneys and the testicles. In 30 p. 100 of the cases, a translocation of the BCL-9 gene or the BCL-6 gene encoding a transcription-inhibiting protein is found. Translocations involving the C-MYC gene have also been described.

10. Burkitt lymphoma is derived from B lymphocytes immortalized by the EBV genome. The malignant cells are monomorphic, medium-sized and have a large nucleus with many nucleoli. The cytoplasm is highly basophile. Infiltration by engulfing macrophages from apoptotic tumor cells produces the histological image of a "star Sky". Burkitt's lymphomas often reach children. In adults, they are associated with immune deficiency, mainly due to HIV infection. The disease is endemic in Africa where it typically reaches the maxillary bones. In the majority of cases, there is a translocation of the C-MYC gene from chromosome 8 near the heavy chain genes on chromosome 14. The T (2; 8) and T (8; 22) translocations placing C-Myc in the genomic regions of light chains are rarer.

11. High malignancy lymphoma similar to the Burkitt type can be derived from proliferating peripheral B cells. Lean morphology and immunological phenotype similar to Burkitt lymphoma, translocation does not involve the C-MYC gene but (in 30 p. 100 of the cases) the BCL-2 gene.