Cytology may be performed on your pet at your veterinarian’s office. A cytologic evaluation is often the first diagnostic test performed by your pet’s veterinarian when a malignancy is suspected, or needs ruled out. Cytology allows your pet’s veterinarian to determine the microscopic appearance of cells where a malignancy is suspected. This is often a low risk procedure and in most cases, your pet does not need to be sedated. A cytologic evaluation can be performed through a fine needle aspirate (cells are drawn into the needle shaft, then placed on a microscope slide for evaluation), scraping the skin or mass and making an impression on the microscope slide, or even just a gentle brush of a mucous membrane. Cytologic evaluations are an important first step to determining the cellular appearance of a suspected malignancy. It is recommended to have most cytologies reviewed by a clinical pathologist for confirmation of a diagnosis.
Biopsy refers to the removal of all or part of a tumor in order to determine the cellular make-up of the mass. Biopsies are sent to a veterinary pathologist after removal. A veterinary pathologist is a veterinarian that specializes in the study of tissues. A veterinary pathologist can determine whether the tissue contains malignant or benign cells. Veterinary pathologists can also help determine the type of tumor the tissue was removed from, as well as indicate whether the tumor was completely removed during surgery, or if cancerous cells around the surgical site still remain.
Clinical Staging refers to the extent involvement of the cancer in the patient. Staging will help determine whether the cancer has remained local, metastasized regionally, or if it has metastasized distantly. The first step in clinical staging is to find the primary tumor and assessing its size. A number of diagnostic methods may be used to determine the size and exact location of the primary tumor. Assessment of the draining lymph node(s) can also be used to determine regional metastasis, and additional diagnostics such as chest or abdominal radiographs or advanced imaging, such as ultrasounds or computed tomography, may help determine if the malignancy has traveled distant to the primary site.
Outside Laboratory Work
Because some cancers are rare, or need additional diagnostics, samples may be sent to outside laboratories for further analysis. Flow Cytometry is one of the most common analyses used to diagnose and monitor cancers such as blood and lymphatic cancers (leukemia and lymphoma, respectively).