Summary NEOPLASTIC DISEASE AND ITS MANAGEMENT INTRODUCTION. Detailed notes

Neoplasia: • state of excessive proliferation of cells • No relation to normal growth and tissue repair. • neoplasm or tumor=abnormal tissue mass • rate of proliferation – ranges from slightly above normal to – wild uncontrolled growth – extends and damages adjacent tissues. – rarely exceeds the fastest normal rate of cell multiplication embryonic development, intestinal mucosal cells, blood and skin. Neoplasia excludes abnormally rapidly cell growths Metaplasia- change from a more specialized cell to a less specialized cell due to • prolonged irritation or • chronic infection eg • columnal epithelium cell more resistant squamous epithelium cells (proliferate very rapidly) • fibroblasts into osteoblasts giving rise to new excessive bone growth • Dysplasia: disorganization of the pattern of squamous epithelium in tissues e.g. skin, eosophagus and uterus -due to chronic irritation or inflammation. increase in cell numbers, thickening of the epithelium. NB :metaplasias and dysplasias are usually reversible. may progress to neoplasias ( pre cancerous states). e.g. chronic hypoxia erythrocyte production and to a physiological polycythaemia, Parathyroid over activity fibrous tumor –like growth of fibrous tissue in bones . Broad classification of Neoplasms (tumors): 2 Broad Classes • Benign tumors • Malignant tumors; Both represent extremes of a spectrum of characteristics of tumor growth – tumors of intermediate type occur combining the properties of both – tumors may also slowly convert from one type to the other, Benign tumor (simple tumor) Characteristics • usually have slow rate of growth which may cease • Cells are well differentiated • Cells resemble those of original tissue: • edge of the tumor well defined • Capsulated (pressure of surrounding react by forming a capsule around the tumor • Clinical disorders from benign tumors normally arise from mechanical obstruction of viscera or pressure on nerves.