LIBRARY Nature.-Angioma is essentially benign, and may continue through life without enlarging. Hemorrhage and inflammatory or necrotic changes are its dangerous consequences. LYMPHADENOMA. Definition. This term is here used to designate a more or less malignant form of new-growth affecting the lymphatic glands or other lymphadenoid tissues, and having the structure of lymphatic tissue. The lymphadenomata may be considered as forms of sarcoma, or at least as closely allied to sarcoma. The term lymphosarcoma is sometimes applied, but is more appropriately given to growths of a more definite malignant nature, having the reticulated structure of lymphadenoid tissue. Other names applied to lymphadenoma are malignant lymphoma and lymphoma. Etiology. It is exceedingly difficult to establish the limitations of the term, and especially to decide whether or not certain cases in which definite etiologic factors have been discovered belong to the group under consideration or should be separated. There are cases of infectious enlargement of the glands and traumatic swellings that cannot be distinguished histologically. In some cases even the clinical course is the same and a separation seems impossible. For example, the glands in a number of instances of Hodgkin's disease (as far as the clinician can establish this diagnosis) have been found to contain tubercle-bacilli. We must conclude that general lymphatic tuberculosis may occur in the clinical form of Hodgkin's disease, but cannot assert that all cases of the latter are tuberculous. In other cases various micrococci and bacilli have been found, but none of these organisms have been shown to be specific. In a few instances bodies resembling protozoa have been discovered. Appearance and Seats.-Lymphadenomata present themselves as more or less considerable enlargements of the lymphatic glands of a single group or more commonly of a number of groups in different parts of the body. All of the glands of the group may be involved, or only a few. The individual glands retain their shape, as there is usually no tendency to extension beyond the capsule of the gland. In exceptional cases, however, the process is of a more infiltrating kind and the capsule is penetrated or destroyed. These instances merit the special term lympho sarcoma. Lymphadenomata may be soft or hard, according to the amount of connective tissue and the denseness of the cellular infiltration and proliferation. On section the tumors are found to be grayish or whitish in appearance, and exceptionally may show slight areas of necrosis or softening. Extensive softening is exceedingly rare. The individual glands of the group may be clearly distinct, or may be fused together by interglandular connective-tissue overgrowth or by the penetration of the lymphadenomatous process through the capsule. When superficial lymphatic groups are involved tumors of various sizes are produced, and project as knobby or rounded enlargements beneath the skin. The latter is freely movable over the tumor unless the growth has penetrated the capsule or secondary inflammatory changes have occurred. In the case of internal FIG. 47-Lymphadenoma (lymphosarcoma) probably originating in remnant of thymus gland: the tumor covered the upper part of the heart like a hood. The illustration shows the tumor turned upward and exposing the pericardium on its under surface. glands large intrathoracic or abdominal growths may be formed, and may exercise destructive compression of vital parts. Similar lymphadenomatous growths may spring from the lymphatic tissues of the gastro-intestinal tract-tonsils, lymphatic follicles of gastric and intestinal mucosa. Sometimes the primary growth seems to begin in the thymus gland or its remnant (Fig. 47). Tumors of considerable size are produced in these cases, and their origin is recognized by their shape (two lateral parts united by a sort of isthmus) and by the absence of the appearance of a conglomeration of glands. In these cases the adjacent glands, and later more distant groups, are involved. Lymphadenoma may be confined to the glands, but frequently extends to the solid organs by metastasis. The spleen, liver, and kidneys are the organs most frequently affected. They become enlarged and indurated, and on section show light-colored areas of lymphadenoid tissue. Similar "lymphoid infiltration" may be seen in the heart, lungs, or other parts. Lymphadenoma may affect the bone-marrow secondarily and perhaps primarily. (Reference will be made to this under the title Myeloma.) Sometimes the tumors have a yellow or green color and are called chloromata (q. v.). Structure. The finer structure of lymphadenomata is precisely that of lymphadenoid tissues. There is a reticulum, more or less pronounced, formed by branching cells which are united by their prolonged extremities. In the meshes of this lie round cells containing large rounded nuclei. The cells are perhaps less uniform in size than those of normal lymphatic glands and large cells are more abundant. The secondary lymphomatous infiltrations of the spleen, liver, etc., have similar structure, but the reticulum is less distinct. Sometimes this may not be apparent in the primary growths; in such instances the tumor is likely to be considered a simple round-celled sarcoma. Nature.-Lymphadenoma is variably malignant. In a small proportion of the cases this malignancy is of local character-that is, the growth tends to invade the neighboring parts. In most instances there is rather a tendency to general involvement of the lymphatic system, with metastatic deposits in various organs. To cases of this kind the terms Hodgkin's disease, pseudoleukemia, and adenia have been given. These cases present themselves in the form of a progressive anemia (lymphatic anemia-Wilks), often with irregularly relapsing fever (chronic relapsing fever-Epstein), and especially with lymphadenomatous tumors in the superficial or deep lymphatic groups (axillary, cervical, inguinal, mediastinal, or abdominal). The disease progresses more or less rapidly, and terminates in death from cachexia and exhaustion in from one to three years. Occasionally the course is rapid, repeated hemorrhages or purpura may occur, and a fatal termination is reached in a few weeks or months. The whole course of the disease is suggestive of an infectious process. The relation of cases like the above and leukemia is certainly very close. The glandular tumors and the secondary changes in the organs are the same, excepting that the lymphatic glands are more prominently involved in ordinary lymphadenoma. The only striking difference is found in the blood. In leukemia there is marked and characteristic leukocytosis; in the other condition this is absent. Many cases have, however, been observed in which Hodgkin's disease has become leukemia; and some authors do not hesitate to speak of the two diseases as identical and representing merely two stages of a common affection. According to this view, we might classify cases as leukemic or aleukemic lymphadenoma. This view seems to me well grounded. The blood in aleukemic cases shows more or less pronounced reduction in the number of red cells, and a normal, reduced, occasionally a moderately increased, proportion of leukocytes. The mononuclear leukocytes are sometimes in relative excess. In acute cases nucleated red cells may be found. The causes and nature of the irregular fever are uncertain. It may be due to an infectious cause, or may be the result of breaking up of leukocytes and liberation of ferments. Multiple Myeloma.-This growth affects the sternum, ribs, vertebræ, skull, and less frequently other bones. The tumor at first suggests a hyperplastic condition of the marrow; later the substance of the bone is replaced by the growth, which may finally break through the shell of bone covering it and invade the soft tissues. Metastasis is very rare. The growth has a mottled grayish and reddish appearance and is rather soft. Microscopically it is composed of small round cells and a vascular network of thin-walled vessels. The cells resemble small myelocytes, or possibly in some cases plasma-cells. SARCOMA. Definition. The term sarcoma is applied to tumors composed of connective-tissue cells with very little intercellular substance. It is often said that sarcoma-cells resemble those of embryonal connective tissue; more properly speaking, they may be likened to the ordinary connective-tissue cell falling short of complete development. There is little tendency in sarcoma to the formation of fibrous intercellular substance, but a great tendency to continuous cell-proliferation. Etiology. Of all the tumors sarcoma furnishes the best ground for Cohnheim's theory. Its frequent occurrence in young persons, the relation of melanosarcomata to congenital pigmentspots of the skin, and the sarcomatous mixed tumors of the parotid and testis were cited by Cohnheim among the evidences pointing to a congenital origin. Traumatism and inflammation certainly play some part, either in stimulating sudden growth of a latent sarcoma or in developing a lesion from which sarcoma springs. The parasitic theory has gained many adherents in recent years. The resemblance to tubercle is very striking in certain cases and the peculiar dissemination is most suggestive. No specific form of bacteria, however, has been demonstrated, and experiments at implantation of the disease in animals have been unsatisfactory (von Eiselberg, Duplay and Cazin). Recently intracellular protozoan organisms have been described, but whether these are really organisms or cellular degenerations is doubtful. In some cases the structures described are certainly nuclear degenerations. It is not improbable that lymphosarcomata are due to the action of bacteria. In connection with the supposed infectious nature of sarcoma it is of interest to note that a relationship has been observed between syphilis and sarcoma. This is based on the fact that some cases disappear under antisyphilitic treatment. Appearances.-Sarcomata are generally more or less rounded tumors often enclosed by capsule; they may, however, be irregular, infiltrating, and therefore unencapsulated. Some forms appear on surfaces, spreading as flat elevations more or less irregular in outline. The consistency is soft or hard according to the number of cells and the amount of intercellular substance, or according to the kind and amount of associated tissue (myxomatous, chondromatous). Typical sarcoma, as the name implies (oáps, flesh), is fleshlike in consistency, and frequently on section the color is pink or of a flesh-tint. Many of the sarcomata, however, are quite white or gray, and a whitish liquid exudes from the surface on section. Dilatation of the blood-vessels may cause a decidedly hemorrhagic appearance, and actual hemorrhages may take place, causing FIG. 48.-Secondary sarcomata of the lung: the primary growth was attached to the pleura. blood-cysts or, subsequently, serous cysts. Other degenerative changes, such as necrosis, mucoid change, and simple liquefactionnecrosis, may render sarcomata soft and often cystic. Sarcomata of glandular organs like the breast may present a cystic appearance in consequence of compression of the glandular ducts and acini and subsequent dilatation. Angiosarcomata (the variety in which sarcoma-cells spring |