PET HEALTH CARE ARTICLES

Plasma cell tumors develop as a result of dysregulated production of plasma cells and are relatively uncommon in dogs and cats. Some plasma cell tumors are benign and the most common locations for these tumors are the head, feet, lips, mouth, and ears. The treatment of choice for benign plasma cell tumors is surgical removal, with little to no recurrence if completely excised. Conversely, multiple myeloma is a very malignant cancer that is usually treated with chemotherapy.

Ovarian tumors are quite rare in North American pets, mainly due to routine spaying practices. This handout discusses ovarian tumors in dogs and cats. The various forms of ovarian tumors, clinical signs, diagnosis, treatment, and prognosis of this cancer are outlined.

Parathyroid tumors are uncommon in dogs and cats. Benign adenomas occur more often than malignant tumors. Keeshonds appear to have a genetic predisposition to developing parathyroid tumors, but no breed or genetic relationship has been established in cats. Pets may exhibit signs of lethargy, little or no appetite, vomiting, and muscle twitching. Diagnosis is confirmed with PTH testing and ultrasound of the neck region after hypercalcemia is observed on bloodwork. Surgery to remove the affected gland(s) is the typical treatment, but ultrasound-guided ablation may be pursued. Careful monitoring of calcium levels post-surgery is important, as some pets may develop transient hypocalcemia and require calcium supplementation. Prognosis is excellent, and the metastatic rate for these tumors is extremely low.

Osteosarcomas are somewhat rare in cats and progress slowly. Osteosarcoma is very painful. The most common location where osteosarcomas develop in cats is the hindlimb. Amputation is by far the most common treatment. Chemotherapy is not generally pursued without evidence of metastasis, given the relatively long-term control with surgery alone.

Primary pancreatic tumors are rare in dogs and cats. Exocrine tumors include adenomas and adenocarcinomas, and endocrine tumors include insulinomas, gastrinomas, and glucagonomas. Insulinomas are the most common type of pancreatic tumor, followed by adenocarcinomas. Both tumors are more common in dogs than cats. Large breed dogs and Siamese cats may be predisposed. Insulinomas are usually diagnosed with the finding of hypoglycemia with normal to high insulin on bloodwork and concomitant clinical signs. Adenocarcinomas typically go undetected until the clinical signs of metastasis are evident. For both tumors, diagnostic imaging and exploratory surgery with tumor removal (or biopsy) and histopathology are needed for a definitive diagnosis. Insulinomas can be treated with surgery and chemotherapy. Surgery is possible with adenocarcinomas, but as the cancer is more diffuse and has usually metastasized by the time of diagnosis, the prognosis is poorer. Chemotherapy and radiation therapy are ineffective in the treatment of adenocarcinomas. Given the high rate of metastasis with these tumors, staging is recommended prior to surgery.

This handout discusses some of the more common forms of oral tumors in pets. Highlighted are Papillomas (“Warts”) and Fibropapillomas, both of wish are caused by viral infection. Clinical signs, diagnostic methods, and treatment options are highlighted.

The most common oral tumor seen in cats is squamous cell carcinoma; the second most common is fibrosarcoma. This handout discusses the clinical signs, diagnosis and treatment of oral tumors in cats.

Odontogenic fibromas, sometimes previously referred to as an epulis, are benign tumors of the mouth often at the front of the upper jaw. These may be locally invasive and may cause some oral pain. Surgery is the recommended course of action to treat this condition.

Fibrosarcomas are the second most common oral tumor in cats and arise from the fibrous and connective tissues of the oral cavity. These tumors are very invasive locally and are often difficult to manage, Diagnosis is based on biopsy and treatment involves surgery and occasionally radiation or chemotherapy. Palliative care with pain relief and antibiotics are essential to improve quality of life.

Neuroendocrine tumors are a group of tumors that develop from the cells of the neuroendocrine system, and include insulinomas, gastrinomas, glucagonomas, carcinoids, medullary thyroid carcinomas, small-cell lung carcinomas, pheochromocytomas, chemodectomas, and Merkel cell carcinomas. Some of these tumors are functional, while others are non-functional. The signs of disease in dogs and cats depend on the type of growth, location of the tumor, its size, the degree of infiltration in the surrounding tissues, whether it has metastasized, and whether it is functional. A definitive diagnosis requires tissue biopsy and histopathology, often with histochemical staining and electron microscopy. Staging is highly recommended for these tumors. Treatment may involve surgery, chemotherapy, radiation therapy, and medical and dietary management.