Laryngeal Tumors

17 Laryngeal Tumors



Leslie E. Fox



1. What are some of the most common tumors of the larynx in the dog?

Laryngeal tumors are rare. A wide variety of tumors have been reported in dogs; however, carcinomas and striated muscle tumors are most common.


2. What is a laryngeal oncocytoma?

An oncocytoma is a benign tumor presumed to be of epithelial origin with a characteristic ultrastructural cell morphology of abundant cytoplasm with enlarged, closely packed mitochondria. Although difficult to differentiate from poorly differentiated striated muscle cell tumors without immunohistochemistry, the distinction is clinically important because they may have a less aggressive biologic behavior.


3. What is the typical signalment for dogs with laryngeal tumors?

There is no breed or gender predilection for dogs with laryngeal tumors. Most dogs are about 7 years old and can be as young as 1 year old. Osteochondromas occur in growing dogs.


4. What typical clinical signs are associated with laryngeal tumors?

Clinical signs are often present for months before diagnosis. When clinical signs are present, dyspnea, voice change or loss, respiratory stridor/stertor, cough, and exercise intolerance are most frequent. Dysphagia, cyanosis, hemoptysis, sneezing, and ptyalism may also be noted. Clinical signs may have been present for months before diagnosis. The severity of the signs depends directly on the extent of airway obstruction.


5. What are the differential diagnoses for dogs with clinical signs referable to the larynx?

In appropriate breeds, elongated soft palate, epiglottic entrapment, and everted laryngeal saccules are seen often with secondary laryngeal mucosal edema. Laryngeal paralysis or collapse, mucosal edema from dyspnea, and excessive laryngeal scar tissue or webbing may be observed. Nonneoplastic masses found in the area of the larynx are laryngeal cyst, inflammatory polyp, granuloma, and pharyngeal salivary mucocele.


6. What diagnostic tests are most useful to evaluate the larynx?

The astute clinician may palpate a thickened larynx or mass dorsal to the larynx and anterior trachea, but, typically, a suspicion of laryngeal neoplasia is raised when increased soft-tissue density in the area of the larynx with or without calcification or distortion of larynx structures are observed on the lateral view of a survey radiograph. Evidence of local metastasis to regional lymph nodes may be seen. Thoracic plain radiography is useful to look for evidence of metastatic disease and changes that accompany upper chronic and severe upper airway obstruction, such as pulmonary edema or aspiration pneumonia. Clinicopathologic tests do not contribute to a diagnosis, but should be done before anesthesia and biopsy.


Direct visualization of the pharynx and larynx via light laryngoscopy is most helpful in differentiating various disorders of the larynx. A flexible fiberoptic endoscope is used to assess the distal larynx and trachea. Using ultrasound, a laryngeal mass may be hypoechoic or of mixed echogenicity with indistinct or distinct borders. Advanced imaging with computed tomography/magnetic resonance imaging allows the most accurate assessment of local invasion and regional lymph node status before surgical extirpation of the tumor.


Histopathologic diagnosis from a tissue sample is needed to definitively diagnose laryngeal tumors. Tissue biopsy under direct visualization of the larynx is often possible. Placement of a tracheostomy tube may be needed before biopsy if the airway is severely occluded. Corticosteroids administered in the perioperative period may help decrease laryngeal mucosal edema secondary to traumatic intubation and tissue manipulation. Careful extubation with an inflated endotracheal tube cuff in place will help prevent aspiration. Percutaneous ultrasound-guided fine needle aspiration is a safe and rewarding method to obtain a cellular sample for cytologic examination.

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Jul 31, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on Laryngeal Tumors

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