PART II. PRACTICE OF SURGERY
SECTION III. DISEASES
Part 15. 5. Tumours
As the result of a local irritation an acute inflammatory swelling tumours, may appear. If the irritant is of a severe type the result may be local death. An abscess may form ; and, after the pus has escaped or has been evacuated, and after the original cause of the irritation has subsided, the swelling may disappear and the parts be restored to a condition nearly allied to the normal. If the irritant, however, is slight and its action prolonged, a chronic inflammatory swelling of the part may result. Although in many cases with appropriate treatment the induration disappears, in other cases it persists during the life of the individual. The indurated mass in its microscopic characters closely resembles the original anatomical characteristics of the part affected. When, for example, an organ like a gland is the seat of a chronic irritation a general increase in its size takes place. A hypertrophy or overgrowth has occurred, hut as a rule the hypertrophied gland is only altered in size ; it retains its general shape and functional activity. Occasionally the hypertrophic area is localized, and to a great extent separable from the original gland by a more or less distinct capsule. In the mammary gland, for Various example, a local hypertrophy may occur, the microscopic characters forms of of which resemble imperfect gland tissue. Between this condition tumour, and an adenoid or glandular tumour of the mamma no distinct line of demarcation can be drawn, and the probability is that the ade-nomatous tumour of the mamma is caused by local irritation. It may be the immediate outcome of a misdirected or excessive functional activity. The great practical difference, however, between it and true hypertrophy is this, that it can only be removed by operation. The adenomatous tumour closely resembles in some of its microscopic characters one of the varieties of epithelioma, of which an increase in the columnar epithelium lining the acini in the gland is the main characteristic. This tumour is not a simple tumour like the true adenoma ; it does not grow slowly ; it is not encap-sulated ; the cellular elements in it not only invade the surrounding tissues but tend to pass into the lymphatic vessels and reach the lymphatic glands in the arm-pit, where they grow and form second-ary tumours similar in microscopic characters to the original growth. From these secondary foci a further invasion may take place, and the cell elements may reach the blood-stream and be caught in the capillaries, forming there new growths, till the patient dies from the general implication of the whole system. This form of tumour has been termed a malignant adenoma. While it has originally the microscopic characters of a simple adenoma, if we look to its life history we have in it an excellent example of a malignant tumour. Microscopically it is a stepping-stone between the simple and the malignant type of tumour ; clinically it is characteristically malig-nant. The mammary gland is composed of glandular tissue and fibrous tissue. A hyperplasia of the fibrous tissue may occur in consequence of an excessive irritation of the glandular tissue, or apparently a primary increase in the fibrous tissue may occur locally, giving rise to a simple fibrous tumour of the mamma, of which fully developed fibrous tissue is the microscopic characteristic. This overgrowth may become encapsulated and give rise to no symptoms except those referable to its gradual increase in size, and after the gland in which it lies has fulfilled its life history it may stop growing, degenerate, and decay. In the uterus, e.g., those fibrous tumours which occur after the time of child-bearing is past, after the uterus has fulfilled its destiny, cease to give any further trouble and are only inconvenient in consequence of their size. Fibrous tissue in the early stages of its development is largely composed of cell elements, and there are tumours, e.g., in connexion with the mamma, which have their prototype in the undeveloped or cellular stage of fibrous tissue. These tumours also are essentially malignant. They grow rapidly, and are richly supplied with thin-walled blood-vessels ; the elements of the tumour pass directly into the blood-stream, and reach the capillaries, where they are arrested and where secondary growths like the original growth in their anatomical characteristics are formed, causing the death of the patient.
In what has just been said it will be seen that there is no distinct line of demarcation between the inflammatory swelling and the hypertrophy, between the hypertrophy and the tumour proper, between the simple and the malignant tumour. The local irrita-tion can be traced in the case of the inflammatory swelling and the hypertrophy, and it is highly probable that both the simple and the malignant tumour are also due to local irritation. It must, however, be acknowledged that it cannot always be traced. If the malignant tumour is not due to local irritation, but to a general dyscrasia or peculiarity of the patient, the surgeon has slight grounds for recommending its removal. If, however, he believes that all tumours are evidences of local irritation, he is fully justified in recommending their early and complete removalin the case of the malignant tumours before they have time to spread by the lymphatic or blood-stream to distant parts, in the case of simple tumours before they have assumed characteristics of malignancy, as these tumours sometimes do. The mammary gland has been taken as an example of an organ in which tumours frequently occur. The reason for this frequency, if we believe in local irritation as a cause of tumour-growth, is not far to seek : from the time of puberty to the time when it terminates its functional activity this gland is in a constant state of vascular unrest and functional change. Both forms of tu-mour are met with in all the organs and tissues of the body. Simple tumours are generally composed of fully developed tissue, similar to the tissue in which they lie, the simple fatty tumour occurring in connexion with fatty tissue, the simple fibrous tumour in con-nexion with fibrous tissue, the osseous tumour in connexion with bone. The malignant tumour, on the other hand, is generally formed of undeveloped tissue wdiieh has not yet fulfilled its destiny, which is not only misplaced in situation but in time. The carti-laginous tumour has its prototype in cartilage, for that which covers the ends of the long bones and enters into the formation of a joint is a fully developed tissue. The true prototype of the cartilaginous tumour is not, however, fully developed cartilage, but one or other of those forms of cartilage which, as regards their developmental position, are intermediate between fibrous tissue and bone, and therefore the cartilaginous tumour has frequently a life history more closely allied to the malignant than to the simple type of tumour formation.
No attempt can here be made to classify the different forms of tumour. The surgeon at the bedside meets with tumours as living parasitic formations. He studies their life history ; he observes their birth, their growth, their peculiarities, and their tendencies ; he naturally attempts to classify them from a study of their physio-logical or clinical aspects. The pathologist, on the other hand, examines the tumour after it is removed ; he studies it as it appears to the naked eye and under the microscope ; and he attempts to classify tumours from an anatomical standpoint. Within recent years the pathologist's classification, associated with a recognition of the developmental division of the human embryo into different layers, has become the favourite ; but it is hoped that, as science advances, the increase of clinical knowledge, assisted by microscopic and embryological research, will make a physiological classification a reality.
687-1 Compare PATHOLOGY, vol. xviii. p. 367 sq.
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