Porth's Essentials of Pathophysiology, 4e
131
Neoplasia
C h a p t e r 7
TABLE 7-1 Names of Selected Benign and Malignant Tumors According toTissueTypes TissueType BenignTumors MalignantTumors
Epithelial Surface Glandular Connective Fibrous
Papilloma Adenoma
Squamous cell carcinoma
Adenocarcinoma
Fibroma Lipoma
Fibrosarcoma Liposarcoma
Adipose Cartilage
Chondroma
Chondrosarcoma Osteosarcoma Hemangiosarcoma Lymphangiosarcoma
Bone
Osteoma
Blood vessels Lymph vessels Lymph tissue
Hemangioma Lymphangioma
Lymphosarcoma
Muscle Smooth Striated
Leiomyoma
Leiomyosarcoma
Rhabdomyoma
Rhabdomyosarcoma
Neural Tissue Nerve cell
Neuroma
Neuroblastoma
Glial tissue
Glioma
Glioblastoma, astrocytoma, medulloblastoma, oligodendroglioma
Nerve sheaths
Neurilemmoma
Neurilemmal sarcoma Meningeal sarcoma
Meninges
Meningioma
Hematologic Granulocytic Erythrocytic Plasma cells Lymphocytic
Myelocytic leukemia Erythrocytic leukemia Multiple myeloma
Lymphocytic leukemia or lymphoma
Monocytic
Monocytic leukemia
Endothelial Tissue Blood vessels
Hemangioma Lymphangioma
Hemangiosarcoma Lymphangiosarcoma
Lymph vessels
Benign Neoplasms Benign tumors are composed of well-differentiated cells that resemble the cells of the tissues of origin and are generally characterized by a slow, progressive rate of growth that may come to a standstill or regress. 2,3 For unknown reasons, benign tumors have lost the ability to suppress the genetic program for cell proliferation but have retained the program for normal cell differentiation.
They grow by expansion and remain localized to their site of origin and do not have the capacity to infiltrate, invade, or metastasize to distant sites. Because they expand slowly, they develop a surrounding rim of com- pressed connective tissue called a fibrous capsule . 3 The capsule is responsible for a sharp line of demarcation between the benign tumor and the adjacent tissues, a factor that facilitates surgical removal.
TABLE 7-2 Characteristics of Benign and Malignant Neoplasms Characteristics Benign
Malignant
Cell characteristics
Well-differentiated cells that resemble cells in the tissue of origin
Cells are undifferentiated, with anaplasia and atypical structure that often bears little resemblance to cells in the tissue of origin Variable and depends on level of differentiation; the more undifferentiated the cells, the more rapid the rate of growth Grows by invasion, sending out processes that infiltrate the surrounding tissues Gains access to blood and lymph channels to metastasize to other areas of the body
Rate of growth
Usually progressive and slow; may come to a standstill or regress
Mode of growth
Grows by expansion without invading the surrounding tissues; usually encapsulated
Metastasis
Does not spread by metastasis
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