Hematopathology: Lymphomas & Myeloproliferative Neoplasms PDF

Hematopathology : Hawler Medical University College of Medicine Department: Pathology Session: the lymphoid system Hawler Medical University College of Medicine Department: Pathology Objectives: Define lym...

Hematopathology : Hawler Medical University College of Medicine Department: Pathology Session: the lymphoid system Hawler Medical University College of Medicine Department: Pathology Objectives: Define lymphomas and understand the major differences between Hodgkin’s and Non Hodgkin’s Lymphoma. Be able to identify the different histological subtypes of Hodgkin's disease. Be able to identify two important examples of NHL, namely Burkitt’s lymphoma and large cell lymphoma. Contents: Lymphoid system: - Reactive nodular hyperplasia - Lymphomas: -Hodgkin’s disease -NHL Normal lymph node Reactive Hyperplasia – L.N Follicular type At the top is the capsule and just under that a subcapsular sinus where lymphatics enter that drain tissues peripheral to the node. Beneath the capsule is the paracortical zone with lymphoid follicles having a pale germinal center in which the immune responses are often generated. Beneath this are sinusoids extending to the center of the node. Reactive Hyperplasia – L.N Follicular type At high magnification is seen a lymph node follicle with a germinal center containing larger lymphocytes undergoing activation. At the lower right is the sub capsular sinus. Lymphomas Lymphomas are a group of diseases caused by malignant lymphocytes that accumulate in lymph nodes and cause the characteristic clinical features of lymphadenopathy. Occasionally, they may spill over into blood ('leukaemic phase') or infiltrate organs outside the lymphoid tissue. Subdivided into: Hodgkin’s Disease. Non - Hodgkin’s Lymphomas. Hodgkin’s lymphoma: Reed - Sternberg (R.S) cells. Arise in a single node / chain of nodes & spreads characteristically to contiguous L.N Clinically: Most patients present with painless, non-tender, asymmetrical, firm, discrete and rubbery enlarge- ment of superficial lymph nodes Constitutional symptoms are prominent in patients with widespread disease. These may include: fever, profuse sweating, weight loss and pruritits. Hodgkin Lymphoma-Gross appearance Enlargement of cervical nodes(most frequent). Individual nodes discrete. C/S grayish tan or pale tan. Hodgkin’s lymphoma: Reed-Sternberg cell: True neoplastic element in HL. Classic RS cells are large ,15 - 45 microns , binucleated / bilobed. Nucleus contains large inclusion like owl eyed nucleoli surrounded by a clear halo. Cytoplasm - abundant & weakly esinophilic. Histology of H.L. (WHO classification): 1. Nodular sclerosis: Reed-Sternberg cell / lacunar variant. Collagen bands. Polymorphous background of lymphocytes, eosinophils, plasma cells & macrophages. 2. Mixed cellularity: Reed-Sternberg cells are of classic type &numerous. Diffuse effacement by a heterogeneous population of small lymphocytes ,eosinophils ,plasma cells ,benign macrophages. 3 Lymphocyte depleted: Either dominance of R-S cells and sparse numbers of lymphocytes or a diffuse fibrosis pattern few lymphocytes. 4 Lymphocyte Predominance. Effacement of L.N in vague nodular pattern by infiltrate of small lymphocytes with benign histiocytes. Classic RS cells are few , popcorn variants are common. The usual background esinophils & plasma cells is missing. HODGKIN’S LYMPHOMA – Nodular Sclerosis This is Hodgkin's disease, nodular sclerosis type. Note the bands of pink collagenous tissue dividing the field in this lymph node.. HODGKIN’S LYMPHOMA – Nodular Sclerosis The aggregates of Reed- Sternberg cells and inflammation are separated by broad bands of fibrosis HODGKIN’S LYMPHOMA – Nodular Sclerosis Broad fibrous bands separating the tumor nodules.  HODGKIN’S LYMPHOMA – Nodular Sclerosis These are the lacunar cells which are characteristic for the nodular sclerosis type of H.L, they are scattered large cells with a surrounding prominent clear space, an artifact of formalin fixation.  Hodgkin’s lymphoma- Mixed cellularity (A) At low power, the lymph node appears to be effaced by heterogeneous population, giving a slightly pink color to the node. (B) The Reed- Sternberg variants are few and far between (arrow), with a dominant population of eosinophils (arrowhead). Hodgkin’s lymphoma- Mixed cellularity Hodgkin’s lymphoma, mixed cellularity type. Several mononuclear Hodgkin cells and rare classic Reed- Sternberg cells are present. The polymorphous background cells include mature lymphocytes, histiocytes, and plasma cells.  Hodgkin’s lymphoma- lymphocyte predominence Numerous mature-looking lymphocytes surround scattered, large, pale-staining lymphohistiocytic variants (“popcorn” cells). Non-Hodgkin Lymphomas eg. Burkitt’s lymphoma. Diffuse large B cell lymphoma. Small noncleaved cell lymphoma, Burkitt's type It’s a B cell tumor. High mitotic rate is characteristic. Both endemic & non endemic type Affect the children & young adults & usually arise from extranodal sites. Microscopically: Nodal architecture completely effaced by uniform medium-sized cells with rounded nuclei with coarsely clumped chromatin and 2-5 prominent basophilic nucleoli &Scattered between them are tingible body macrophages with prominent nuclear debris surrounded by clear space, giving the characteristic “starry sky” appearance. Burkitt's lymphoma Burkitt's lymphoma Diffuse large B cell lymphoma Nodal architecture completely effaced by large cells. Open chromatin Prominent nucleoli. Nucleus may round, irregular, or cleaved (typically 3 to 4 lymphocyte diameters). Diffuse large B cell lymphoma Diffuse large B cell lymphoma MyeloproliferativeDr. Neoplasms Nawsherwan (MPNs) Sadiq Investigations ET is a diagnosis of exclusion Rule out other causes of elevated platelet count Infection Tissue damage (surgery) Chronic inflammation Malignancy  Essential Thrombocythemia (ET) Blood film Bone marrow increase platelet increase megakaryocyte Myelofibrosis Investigations Anemia High WBC at presentation Later leucopenia and thrombocytopenia Leucoerythroblastic blood film Tear drops red cells Bone marrow aspiration- Failed due to fibrosis Trephine biopsy- fibrotic hypercellular marrow Increase in NAP score Transformation to acute myeloid leukaemia occurs in 10-20% of patients High serum uric acid and LDH levels Leukoerythroblastic blood picture Tear drop RBCs