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LYMPHOMA. * Def : malignant tumor of the lymphoid system. *Sites: I. Lymphoid tissues: a. Nodal: from lymph nodes. b. Extra nodal: spleen, bone marrow, liver and lymphoid collections (tonsils, adenoids, payer’s patches and solitary lymphoid follicle of the large intestine).
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*Def: malignant tumor of the lymphoid system. *Sites: I. Lymphoid tissues: a. Nodal: from lymph nodes. b. Extra nodal: spleen, bone marrow, liver and lymphoid collections (tonsils, adenoids, payer’s patches and solitary lymphoid follicle of the large intestine). II.Non-lymphoid tissues: as skin, CNS, kidneys & testis. *Classification: I. Hodgkin’s lymphoma. II. Non-Hodgkin’s lymphoma.
HODGKIN’S LYMPHOMA *Incidence: common *Age: 2 peaks: in young adults & in middle age. *Pathology: • -Starts nodal (in axial L.Ns as cervical, mediastinal and para aortic) and then involve the extra nodal tissues and less commonly involve the non-lymphoid tissues.
I. Lymph Nodes: * N/E: • Enlarged, firm, discrete. • C/S: hemorrhage & necrosis. * M/P: Loss of the nodal architecture and replacement by two component;, neoplastic component & inflammatory background.
A. Neoplastic component: (Reed-Sternberg giant cell (RSC)): • Giant cells contain multiple nuclei in the center. • Surrounded by clear halo. The cytoplasm is abundant & esinophilic. • The nuclei are arranged in pairs with mirror image appearance. • The nuclei are vesicular with thick irregular nuclear mm. • The nuclei show prominent esinophilic nucleoli surrounded by clear halo giving Owl eye look. B. Reactive inflammatory background: • Formed of lymphocytes, plasma cells, macrophages, eosinophils & neutrophils with fibrosis.
II. Extra nodal involvement: • Splenomegallyin 75%. • Hepatomegallyin 50%. • Bone marrow in 15%. III. Extra lymphoid organ involvement: Less common.
* Classification of Hodgkin’s lymphoma: A. Classic Hodgkin’s lymphoma: • Nodular sclerosis type. • Mixed cellularity type. • Lymphocytic predominance type. • Lymphocytic depleted type. B. Nodular lymphocytic predominance Hodgkin's lymphoma (NLPHL).
* Systemic manifestation of Hodgkin’s lymphoma: • Includes: • Pel-Ebestein fever. • Anemia. • Leucocytosis. • Eosinophilia. • Pruritis. • Depressed T-cell function. • The patient is classified A (absent manifestation) or B (present manifestation). • When present indicates bad prognosis.
* Staging of lymphoma: • Stage I: involvement of a single L.N region. • Stage II: involvement of two or more L.N regions on the same side of the diaphragm. • Stage III: multiple sites above and below the diaphragm. • Stage IV: involvement of extra lymphatic organs + or – L.N involvement.
NON HODGKIN’S LYMPHOMA (NHL) *Incidence: less common than Hodgkin’s lymphoma. *Age: any age. *Pathology: • The disease may be localized or disseminated from the start. • Extra-nodal & Non-lymphoid tissue involvement is common and may be the first presentation.
Lymph nodes show: • N/E: • Enlarged, soft, fused. • C/S: hemorrhage & necrosis. • M/P: • Loss of normal nodal architecture & replacement by single cell type of transformed lymphocytes.
*Types of NHL: B. Cell lymphomas • Precursor B. cell lymphoma: • Lymphoblastic leukemia/Iymphoma B. Peripheral B. Cell lymphoma: • Chronic Iymphocytic leukemia/small IymphocyticIymphoma. • Diffuse large B. cell lymphoma. • Lymphoplasmacytic lymphoma • Mantle cell Iymphoma. • Follicular Iymphoma • Marginal Zone Lymphoma. • BurkittIymphoma
B-cell lymphomas constitute the vast majority of lymphomas, accounting for nearly 90% of all lymphomas. • Immunosuppression, specifically due to HIV infection and immunosuppressive therapy, is associated with a markedly increased incidence of developing mature B-cell lymphomas, particularly diffuse large B-cell lymphoma and Burkitt's lymphoma.
Diffuse large B-cell lymphoma and follicular lymphoma are the most common types. • Follicular lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, marginal zone B-cell lymphoma and lymphoplasmacytic lymphoma, which are generally indolent lymphoma, but incurable and usually present in a disseminated stage with bone marrow involvement.
Mantle cell lymphoma and diffuse large B-cell lymphoma represent “intermediate-grade B-cell lymphomas” that generally show a more aggressive clinical behavior, but are potentially curable. • Burkitt'slymphoma and precursor B-lymphoblastic leukemia/lymphoma are high-grade B-cell lymphomas.
T. CELL and NK cell lymphomas • Precursor T cell lymphoma: - Lymphoblastic leukemia/lymphoma. B. Peripheral T-cell and NK cells lymphomas: • Aggressive NK cell leukemia • Mycosis fungoides and sezary syndrome . • Angio-immunoblastic T-cell Iymphoma. • Adult T-cell leukemia/lymphoma (HTLV1+). • anaplastic large cell Iymphoma (ALCL). • Peripheral T. cell lymphoma, unspecified.
Mature T. cell and natural killer (NK) cell lymphomas are rare, accounting for only 10% of all Non-Hodgkin lymphoma, and usually are more aggressive than B-cell lymphomas. • The most common subtypes are peripheral T-cell lymphoma, unspecified and anaplastic large cell lymphoma.