| FIG. 53. |
| 1, tumor; 2, aorta; 3, right ventricle of heart. |
In a disease of this rare nature we can best formulate an idea of the character of the growths by the recital of a few typical cases. In an autopsy made by the writer, on removing the sternum and cartilages they were found to be adherent on the right side to a mass which occupied the anterior mediastinum (see Fig. 53). The growth was seven inches long, measuring from the sternal notch, and terminated in a somewhat diffused thickening of the visceral pleura, which covered the anterior margin of the upper and middle lobe of the right lung. The growth was two and a half inches broad. It overlaid the aorta, pulmonary artery, and the vessels of the neck. The calibre of the trachea was slightly diminished. The glands of the neck were unaffected on either side. The posterior mediastinal glands were very slightly enlarged along the sides of the trachea and upper bronchi. Laterally, at the lower portion of the growth, the pulmonary pleura was thickened at the line of contact with the tumor, but the lungs were free from any traces of disease. The new formation was of fibrous consistence, of a gray-white color, and through its centre a softened tissue was found. Microscopic examination showed the growth to be composed of medium-sized lymphoid cells mixed with spindle-shaped cells, and imbedded in a homogeneous stroma or a stroma which consisted of reticulated fibres and wavy fibrous tissue. Other portions of the body were normal.
In West's case the tumor also occupied the anterior mediastinum, extending toward the second left intercostal space. The mass was about the size of a boy's head, soft, cellular, and adherent to the upper lobe of the left lung; it also rose into the episternal notch and left supra-clavicular fossa. The brachial plexus and vessels of the left side, subclavian and carotid arteries, the jugular and innominate veins, were imbedded in the tumor. The left bronchus and a portion of the trachea were flattened. The left phrenic and left pneumogastric nerves passed through the mass, and on dissection were found much thickened as they ran through the tumor. The tenth nerve measured three times its normal diameter, and was pushed out of its course nearly an inch from the carotid. The recurrent laryngeal was also thickened; the right pneumogastric and phrenic nerves were not involved. The heart lay beneath the tumor; nodules of the new growth were found upon the anterior surface of the heart and along the vessels issuing from it. No secondary deposit was found in the lungs except at the margin of the left upper lobe, into which the tumor spread directly. The spleen, liver, kidneys, and lumbar glands were normal.
Microscopic examination determined the growth to be a round-celled sarcoma, the thickening of the nerves being due to infiltration by similar small-celled growth.
In primary sarcoma of the mediastinum—and the same is true of lymphadenoma—the invasion of the various intra-thoracic organs is chiefly by continuity or direct spreading of the growth. The lymphatics of the neck are very rarely implicated in this form of malignant disease; and while in lympho-sarcoma the glands may be involved, they are not so frequently as in cancerous processes. Sarcomata of the mediastinum with implication of the lungs and pleura are more frequently secondary processes; indeed, the lungs would seem never to be the seat of primary sarcoma. The pleural tissues, however, may be primarily involved. Lepine, Birch-Hirschfeld, Böhme, Eppinger, Schultz, Greenish, and others have reported cases in which the growths were abundantly distributed in the pleural tissues as primary formations. The point of origin is believed to be either directly from the ordinary connective-tissue cells or from the endothelium of the lymphatics.
Secondary sarcomata may form in the mediastinum or in the lungs within a month or so long as a year after the removal of tumors from other parts of the body, probably by metastasis prior to the removal. In some of these cases the seat of original growth and the neighboring glands may be entirely healthy.
In a typical case of multiple osteoid sarcoma of the lung reported by West fleshy vegetations were found on the visceral pleura: upon the parietal pleura, over the seventh rib, two inches from the spine and growing from it, was a lobular spongy mass as large as an orange, but perfectly disconnected with the parts beneath. The right lung was irregular in shape, owing to the presence of masses of new growth in its different parts. The middle lobe seemed almost completely converted into the new growth. Between the lower lobe and the diaphragm, but attached to the lung, was a mass the size of a cricket-ball, covered with a dark, laminated, but easily separated coagulum. The tumor occupied the upper lobe of the left lung, forming an irregular oval mass six by four and a half inches. It was white in color, and adherent to its upper border was compressed lung-tissue. There were also four or five independent nodules situated near the surface, and of a white color. The lower lobe contained one medium-sized growth and four or five small ones. The bronchial glands were not involved. The tumors appeared soft and spongy, but on incision they were found so hard that a knife could scarcely divide them.
Frequently, the lungs are found infiltrated with sarcomatous nodules of a soft consistency, varying in size from a walnut to an orange. To sum up: primary sarcomata may be the round- or spindle-celled variety; but myeloid sarcomata also occur, chiefly as secondary growths. (See Fig. 54.)