Atlas of pathophysiology, 2 Edition

Part II - Disorders

Hematologic Disorders

Non-Hodgkin's lymphomas

Non-Hodgkin's lymphomas refer to a heterogeneous group of malignant diseases originating in lymph nodes and other lymphoid tissue. Non-Hodgkin's lymphomas are three times more common than Hodgkin's disease. The incidence is increasing, especially in patients with autoimmune disorders and those receiving immunosuppressant treatment.

Causes

·   Direct cause unknown

·   Possible viral etiology

·   Exposure to toxins—benzene, gasoline, pesticides, herbicides

Age Alert

Malignant lymphomas occur in all age-groups, but incidence rises with age (median age is 50).

Pathophysiology

Non-Hodgkin's lymphoma is pathophysiologically similar to Hodgkin's disease, but Reed-Sternberg cells aren't present, and the specific mechanism of lymph node destruction is different. The abnormal lymphoid tissue is identified by its tissue architecture and patterns of infiltration. These lymphomas are defined as follicular, interfollicular, mantle, ormedullary, depending on the distribution of malignant cells in specific regions of the lymph node. The tissue is then described by the pattern of infiltration as diffuse or nodular.

Signs and symptoms

·   Enlarged tonsils and adenoids

·   Painless, rubbery enlargement of lymphatic tissue (lymphadenopathy), usually cervical or supraclavicular nodes

In children

·   Cervical nodes usually affected first

·   Dyspnea and coughing

In advancing disease

·   Symptoms specific to involved structure

·   Systemic complaints—fatigue, malaise, weight loss, fever, night sweats

Diagnostic test results

·   Lymph node biopsy reveals cell type.

·   Biopsy of tonsils, bone marrow, liver, bowel, or skin reveals malignant cells.

·   Complete blood count detects anemia.

·   Uric acid level is elevated or normal.

·   Blood chemistry shows elevated serum calcium levels if bone lesions are present.

·   Bone and chest X-rays, lymphangiography, liver and spleen scans, abdominal computed tomography scan, and excretory urography show evidence of metastasis.

Treatment

·   Radiation therapy—mainly in the early, localized stage of disease

·   Total nodal irradiation

·   Chemotherapy with combinations of antineoplastic agents

·   Autologous or allogeneic blood marrow transplantation

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LYMPHATIC SYSTEM

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Clinical Tip

Cervical Lymphadenopathy

This illustration shows a woman with characteristic lymphadenopathy (of the cervical lymph nodes) due to lymphoma.

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