139 Loc. cit.
The liver is very commonly enlarged, pale, smooth, and retains the normal shape. It may be greatly increased in size, as in case of Walshe's, where it weighed 13½ pounds. The substance is usually firm, of a grayish-brown color, or even marbled. Two chief changes have been met with—a diffuse leukæmic infiltration and numerous small leukæmic tumors. The infiltration may be very slight, and not noticeable with the naked eye, or it may be in the form of irregular scattered areas of a yellowish-white appearance, not distinctly isolated, but merging into the hepatic tissue. When moderate, a section shows the columns of liver-cells to be separated by wide spaces occupied by leucocytes, which are partly within and partly outside of the capillaries. The accumulation of these elements produces atrophy of the liver-cells, and their aggregation and increase in certain regions produce the grayish-white areas, in the midst of which traces of liver-tissue may be found. The defined leukæmic growths are small, not often attaining a large size, and may resemble tubercles. They are usually situated in the interlobular tissue, and consist of lymphoid cells in a well-defined reticulum, and they possibly have a different origin from the diffuse infiltrations.
Fatty degeneration of the liver-cells is a very common change.
The respiratory system is not often the seat of important lesions. Lymphoid growths have been found in the mucous membrane of the trachea and bronchi, and occasionally in the lungs, in which situation they may closely resemble tubercles, but differ from them in not tending to caseate or soften. Oedema of the bases of the lung is almost always found. Many patients are carried off by a low pneumonia. The greenish leukæmic clots projecting from the cut ends of the vessels may give a very curious appearance to the section of the lung. The pleural surfaces may be the seat of lymphoid growths.
The kidneys are usually pale, often enlarged, and show signs of parenchymatous swelling. The capillaries, like those of the liver, may be distended with leucocytes, and leukæmic tumors may occur, generally situated in the cortex and ranging in size from a pea to a cherry. In none of the cases I have examined were there any special changes in these organs beyond slight enlargement and filling of the capillaries with leucocytes.
The generative organs are usually normal. No changes have been found to account for the persistent priapism met with in certain cases.
The meninges of the brain, the veins, and sinuses, are often filled with grayish clots. Occasionally meningitis has been found, with exudation of lymph. The small vessels of the brain may be plugged with leucocytes, forming thrombi, from which softening results. Cerebral hemorrhage may prove rapidly fatal. In Case X. of the Montreal series the patient died suddenly, and without any premonition, with a huge apoplexy of the ventricles and posterior part of the hemispheres.
Leukæmic growths in the skin have been described.
The leukæmic tumors demand further consideration. They are not common. In 10 of the 11 Montreal cases careful post-mortem examinations were made, and in not one were there definite new growths. In Case I. there was diffuse leukæmic infiltration of the liver, the histological characters of which were carefully studied. In the 157 cases collected by Gowers140 there were only 13 instances of leukæmic nodules in the liver, and 10 in the kidneys. They are still more uncommon in the lungs. In the spleen—unlike this organ in Hodgkin's disease—they are very rarely seen. The nodules consist of leucocytes in a meshwork of delicate reticular tissue. Their mode of origin has been much discussed. There can be no doubt, I think, that they are new growths of lymphoid tissue of local origin. Possibly they start from accumulations of colorless corpuscles which pass out of the capillaries. In the infiltration of the liver one sees diffuse collections which resemble new growths, but which have evidently resulted from the aggregation in and outside of the capillaries of enormous numbers of leucocytes, which cause the atrophy of the cells of the organ. Doubtless, they multiply in loco by a process of fission, and these aggregations may themselves be foci for the origin and development of colorless cells which pass into the blood-current and augment the number.141 Quite recently Bizzozero has studied the development of these leukæmic new growths, and has shown clearly that the cells which compose them are in process of active fission.
140 Loc. cit.