Chapter XV
TUMORS AND CYSTS
TUMORS
Definition. A tumor is a circumscribed mass of tissue made up of cells of the same kind as the tissue from which it grows.
There are two distinct types of tissue in the body: epithelial and connective, and therefore two types of tumors: the epithelial tissue tumors and the connective tissue tumors.
Tumors may also be classified as typical, and atypical. A typical tumor is one in which the cells are identical to those in the tissue from which it springs, and also has the same arrangement of cells. They may be of epithelial or connective tissue origin. The tissue is identical in all respects and the growth is benign. An atypical tumor is one of epithelial or connective tissue origin in which, though the cells are the same as those in the tissue from which it grows, their arrangement is quite different. They are malignant.
The most important classification of tumors is that into benign and malignant.
A benign tumor is one in which there is no tendency to rapid growth; the symptoms are purely local, and the general health is not affected, except indirectly.
On the other hand a malignant tumor is one which takes on a rapid growth with a tendency to infiltrate or adhere to surrounding tissues; recurs when removed, and is accompanied by great pain and a rapid loss of weight and strength. These are commonly known as cancerous.
Malignant growths are of two types, carcinomatous and sarcomatous, dependent upon the tissue from which they emanate.