Myeloproliferative Disorders (MPDs)

MPDs 1 of 2 Definition: Clonal hematopoietic stem cell diseases that result in expansion and excessive production and overaccumulation of erythrocytes, granulocytes, and platelets in some combination in the bone marrow, peripheral blood, and body tissues They are grouped as myeloproliferative diseases because they may express common clinical features, laboratory changes, and pathogenetic similarities Chronic conditions

MPDs 2 of 2 Most common diseases included in the classification of MPDs: Chronic myelogenous leukemia (CML) Polycythemia rubra vera (PRV or PV) Essential thrombocythemia (ET) Clinically, patients with MPD present in a clinically stable phase that may transform to an aggressive cellular growth phase such as acute leukemia or just a more aggressive form of MPD

Polycythemia rubra vera (PV) A neoplastic, clonal overproduction of erythrocytes, granulocytes, and platelets to some degree (primary problem is too many RBCs) The clonal neoplastic transformation arises in a pluripotential hematopoietic stem cell RBCs are very sensitive to erythropoietin for cell growth Clinical diagnosis: increased red cell mass, maybe increased arterial O2 saturation, and splenomegaly, increased platelet counts or WBC counts Disease progresses to acute leukemia in 15% of cases Primary treatment is therapeutic phlebotomy

Essential Thrombocythemia (ET) Manifests with increased megakaryocytopoiesis and peripheral blood thrombocytosis PLT counts greater than 600,000/μL Complications include thromboembolism and hemorrhage

Lymphoproliferative Disorders

Lymphoproliferative Disorders 1 of 2 Refers to a large group of neoplastic lesions of the lymphoid system Normal lymph nodes are composed of a cortex and medulla; Follicles of varying size and shape are usually present in the cortex Biopsy of lymph node may be submitted for histologic evaluation in formalin; additional fresh tissue may be submitted for ancillary tests, including immunophenotyping, cytogenetics, and molecular diagnostics

Lymphoproliferative Disorders 2 of 2 Most common diseases included in the classification of Lymphoproliferative Disorders are: Hodgkin lymphoma Non-Hodgkin lymphoma Plasma cell dyscrasias Chronic lymphocytic leukemias (CLLs) Other lymphoid proliferations that may behave in an aggressive fashion Neoplastic lymphoproliferative disorders are broadly divided into Hodgkin and non-Hodgkin lymphomas

Malignant Lymphoma Classification systems correctly used for diagnosis include Working Formulation, Revised European-American Classification of Lymphoid Neoplasms (REAL), and World Health Organization (WHO) Subtypes of malignant lymphoma are broadly divided into B-cell and T-cell neoplasms AIDS patients are at high risk for lymphoproliferative disorders, especially aggressive high-grade malignant lymphomas Transplant patients may develop a wide array of post-transplant lymphoproliferative disorders

Hodgkin Lymphoma A malignant lymphoproliferative disorder associated with fevers, night sweats, and cervical adenopathy Diagnosis is characterized by the Reed-Sternberg cell (a large cell with a bilobed or polylobated nucleus and thick nuclear membrane, and looks like “owl eyes”) Extranodal Hodgkin lymphoma may be found in bone marrow, liver or spleen

Non-Hodgkin Lymphoma Includes a heterogenous group of disorders that differe in microscopic appearance, immunologic origin, and biologic behavior

Myelodysplastic Syndromes

Myelodysplastic Syndromes (MDSs) 1 of 3 A group of acquired clonal hematologic disorders characterized by progressive cytopenias in the peripheral blood, and dyspoiesis in the erythroid, myeloid, and/or megakaryocytic cell lines The dyspoiesis is evidenced by abnormal morphologic appearance and abnormal function of the cell lines affected Affect primarily the older population, occurring most frequently among people over 50; Uncommon in children

Myelodysplastic Syndromes (MDSs) 2 of 3 Three types of MDS have been recognized: Primary (de novo) Therapy-related (TR-MDS) Hereditary All are the result of proliferation of abnormal stem cells Currently, the classification of these syndromes is determined by a strict set of morphologic guidelines (FAB), although a new classification system has been proposed that includes molecular, cytogenetic, and immunologic characteristics (WHO)

Myelodysplastic Syndromes (MDSs) 3 of 3 Treatment depends on prognosis, and includes: Supportive therapy Chemotherapy Bone marrow transplant (the only cure)