There comes a time after a dog’s body has reached a certain size and maturity that the natural multiplication of cells by division stops producing new cells. Cells are then produced only to replace dead cells. The body produces new cells only in exceptional cases like a cellular injury.
Such replacement is the necessity of the body. Sometimes there are instances when the system that maintains a balance between the death and growth of cells is unsettled by internal or external factors. This causes the cell production to start producing in an unregulated production mode. This results in a mass of cells, called a tumor, which perform no specific function and are not required by the body.
Not all tumors or cancers in dogs are harmful for the body. Sometimes the cells that grow unnecessarily resemble the normal cells of the organ from which they grow. These are benign tumors.
A benign tumor cannot be identified merely by its shape and has to be examined by a number of diagnostic tests. A biopsy or a sample of the tumor is obtained by performing a simple surgical procedure. It is then examined under a microscope. Benign tumors are normally enclosed in a capsule of fibrous tissue. The tumor is benign if the microscopic examination reveals a resemblance of the cells in the tumor with those of the surrounding organs. Malignant cells do not resemble the normal cells of an organ.
Another difference is that normal cells would show as being inactive while the cells in the tumor would show a greater percentage of cells in the dividing stage. A malignant tumor may sometimes appear similar to benign tumors and can only be differentiated by the presence of an unnatural count of chromosomes.
All types of pet cancers, including feline cancer, follow the same rule of prevalence and growth and therefore can either be benign or malignant. Unfortunately it is difficult to unearth cancer in its early stages because the symptoms of cancer usually mimic symptoms of other conditions. A typical example is that of liver cancer. Symptoms of liver cancer in dogs like a decrease in appetite, refusal to eat, a bloated stomach or excessive vomiting may be symptoms of an inflammation in the liver, a pus filled abscess, or an injury to the liver.
Benign tumors do not spread to other organs. Moreover, the fact that benign tumors are encapsulated in fibrous tissue makes surgical removal of the entire tumor relatively simple. Although malignant tumors may also be similarly encapsulated in their initial stages, in advanced stages they do not remain restricted to the organ from which they develop. Surgery poses a great challenge in such cases. Care has to be taken to remove as much of the tumor as is possible. Even experts cannot guarantee that there are no residual cancerous cells left after surgery. Sometimes a malignant tumor can metastasized to affect certain vital organs ruling out a surgical removal.