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.

The carcinomata spring from the epithelial type of tissue while the sarcomata emanate from the connective tissue type.

Origin. Tumors originate from many causes. Some are congenital and others grow in later life from an inherited tendency.

Any continued irritation which acts mechanically or chemically so as to maintain a constant, though slight, degree of undue vascularity of a part, such as the hot, rough stem of a clay pipe or a jagged tooth, favors the development of a malignant growth. Certain benign growths, such as warts or moles, are especially prone to malignant change. Age and sex also predispose to tumor formation.

Thus carcinoma is a rarity under thirty years of age; the mammary gland of the female is more liable to carcinoma than the male; while on the other hand the esophagus, lip and tongue of the male are more liable to attack.

The possibility of certain malignant growths being of germ origin is thought to be evident (though not yet proven) from many facts. The fact that where there are malignant growths present, lymphatic glands, quite distant from the original growth, become secondarily infected, through the lymphatic vessels, seems to carry out this view.

Particles of a carcinoma (metastasis) floating in the blood stream, finding lodgment elsewhere also establish new growths (metastatic).

Tumors are named according to the tissues from which they arise, thus:

Connective Tissue Tumors

Epithelial Tissue Tumors

CYSTS

Definition. Cysts are hollow tumors filled with fluid or semi-solid contents. They are classified according to their mode of development:

Sebaceous Cyst. A sebaceous cyst is a tumor resulting from retained sebum (secretion of the sebaceous glands).

They sometimes, though rarely, are found on the soles of the feet. They range in size from a millet seed to the size of an egg or larger; they may be globular or flattened. They may be single or multiple; the skin over them is normal in color and smooth, or white if distended, red if inflamed. They grow very slowly and ordinarily persist indefinitely, but calcareous changes are common. Not infrequently they break down and ulcerate. The wall is made up of connective tissue lined with epithelium and the secretion if chemically altered, becomes fluid, semi-fluid, cheesy or purulent.

Treatment. Spontaneous cure often occurs when a cyst becomes inflamed and suppurates. The pus is evacuated either spontaneously or by incision, following which the walls of the sac adhere and its cavity is obliterated.

Treatment directed toward the obliteration of the sac is the only procedure which gives promise of permanent cure; mere puncture and evacuation will effect only temporary relief, the sac soon filling again.

Incision followed by dissection and removal of the sac, either intact or punctured, is radical and efficient.

Puncture and evacuation, followed by swabbing out with pure phenol or strong iodin, may set up an inflammatory reaction within the sac, which acts similarly to the suppurative process, causing adhesion of the walls, thus preventing a recurrence.