This section is from the book "A Manual Of Pathology", by Guthrie McConnell. Also available from Amazon: A Manual Of Pathology.
Primary growths of the liver are very unusual, but it is nearly always involved secondarily in malignant disease of other localities.
Angioma is about the most frequent new growth. It generally occurs upon the surface of the liver as small, circumscribed, dark red or purplish areas that may be single or multiple. Sometimes they may be as large as an orange. They are more common in old, poorly nourished people. The surrounding liver tissue shows no changes. Microscopically the structure is that of a cavernous angioma.
Fibroma, Lipoma, and Myoma are very rarely met with.
Sarcoma may be primary or secondary, the latter being the more usual.
The primary variety is more frequently found in children. It develops from the connective tissue of the hilus or of the periportal tissue and appears either as a round-cell or a spindle-cell growth.
Secondary sarcoma follows as a hematogenous infection from a primary focus elsewhere, and is formed of the same variety of cells as the original growth. Melanotic growths are commonly secondary to sarcoma of the eye.
The liver is increased in size and is the seat of numerous rounded masses varying in size and pale in color.
Adenoma is found in livers that are otherwise normal, and also in cases of cirrhosis. May be single or multiple, nodular, somewhat encapsulated, and grayish or pinkish in color. At times it may be difficult to distinguish adenoma and cirrhosis from carcinoma both by the naked eye and by the microscope.
Hypernephroma, a variety of adenoma that develops from a misplaced fragment of the cortical portion of adrenal tissue, is but rarely seen. The cells in this form are cubical and contain fat and pigments.
Carcinoma may be primary, which is uncommon, or secondary, which is the usual form.
Primary cancer may appear as a large, more or less circumscribed tumor, usually in the right lobe. It probably originates as an adenoma and extends into the surrounding tissues. Microscopically there are seen irregular cell nests surrounded by a well-marked connective-tissue framework. The cells resemble the liver parenchyma, as a rule, but. in places they are smaller and more closely simulate the cells of the bile-ducts. Fatty degeneration, with necrosis and interstitial hemorrhage, is common, and pigment, either biliary or melanotic, is not infrequently present.
Another variety of the primary growth occurs as a diffuse carcinomatous infiltration with a general increase in the size of the organ. The surface of the liver is granular and nodular, and grayish or brownish in color. Larger circumscribed nodules may also be present. Except for the large nodules, the appearance of the organ is very similar to that in cirrhosis.
Microscopically it is seen that the entire tissue is infiltrated by the cancer cells. Surrounding these collections of cells are bands of connective tissue, and lying in between the two is a narrow zone composed of atrophic liver-cells that have been pushed aside by the neoplastic cells. The capillaries are found to be filled with cancer cells and the infiltration may become so great as to obliterate blood-vessels and bile-ducts and completely destroy the function of the liver.
A third variety of primary cancer is the interlobular form. In this the carcinoma has extended along the distribution of the portal vein and invades but slightly the neighboring tissue. The liver appears to the naked eye very much like an atrophic cirrhosis, having the same irregular surface. Is frequently spoken of as cirrhotic cancer.
Secondary cancer is frequently found in cases of primary growths of the stomach, intestine, pancreas, mammary glands, and uterus. Occurs in connection with those organs whose venous blood empties into the portal system. It generally appears in the form of numerous nodules disseminated through the organ. The nodes vary greatly in size, the large ones frequently showing a depressed, umbilicated center, the result of necrosis and softening with absorption. These secondary growths are, as a rule, quite well circumscribed. The cells that compose them resemble more or less closely those of the original neoplasm. Masses of these cells gain entrance into the circulation as emboli, and wherever they lodge they undergo division and give rise to new tumors.