Pneumothorax is an accumulation of air outside the lungs, but inside the chest wall. The air outside the lung prevents the lungs from inflating normally, and can lead to lung collapse. There are several variations of pneumothorax.

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.

Clinical signs of pituitary tumors depend on whether the tumor is functional or non-functional. Functional tumors can cause Cushing’s disease in dogs and can cause acromegaly and insulin-resistant diabetes in cats. Non-functional pituitary tumors can enlarge to cause neurological signs. Diagnosis is based on the history, bloodwork, urinalysis, and sometimes a CT scan or MRI. Medical therapy is often the treatment of choice for functional tumors. Radiation therapy is another option and is usually the primary treatment for non-functional tumors.

Pituitary macroadenomas are large tumors of the pituitary gland that are either functional (secrete hormones) or non-functional (do not secrete hormones). The most common functional pituitary macroadenoma in the dog secretes the hormone ACTH, causing increased cortisol levels and Cushing’s disease. Non-functional macroadenomas cause clinical signs through compression of nearby structures resulting in vision changes, diabetes insipidus, and neurologic disorders. This handout explains the effects of these tumors on dogs, how they are diagnosed, and the treatment options available.

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.