Larynx: neoplasia in Cats (Felis) | Vetlexicon
felis - Articles

Larynx: neoplasia

ISSN 2398-2950

Contributor(s) :


Introduction

  • Rare and usually malignant; either lymphoma or squamous cell carcinoma. Occasional thyroid tumor arising from ectopic thyroid tissue, adenoma or polyp.
  • Cause: feline leukemia virus involvement in lymphoma, otherwise unknown.
  • Signs: dyspnea, inspiratory stridor, dysphagia, dysphonia, collapse, ptyalism.
  • Diagnosis: based on history, clinical signs, laryngoscopy, radiography and histopathology.
  • Treatment: surgery, chemotherapy, radiotherapy.
  • Prognosis: guarded or poor.

Presenting signs

  • Interference with inspiratory airflow and/or deglutition.
Non-laryngeal tumors of surrounding structures may cause similar signs.

Age predisposition

  • Middle to old age.

Special risks

  • Stress: handle with care.
  • Anesthesia: may be difficult to intubate; be prepared for tracheostomy Tracheostomy, temporary tracheostomy.
  • Biopsy: care needed to avoid hemorrhage and aspiration.

Pathogenesis

Pathophysiology

  • Laryngeal or extralaryngeal neoplasia   →   interference with respiratory airflow.
  • Interference with swallowing   →   dysphagia/aspiration pneumonia.

Timecourse

  • Usually short following diagnosis.

Diagnosis

Presenting problems

  • Dysphonia.
  • Cough.
  • Dyspnea.
  • Dysphagia.
  • Cyanosis.
  • Collapse.
  • Ptyalism.

Client history

  • Respiratory stridor.
  • Dysphonia.
  • Dyspnea.
  • Dysphagia.
  • Coughing.

Clinical signs

  • Inspiratory stridor.
  • Dyspnea.
  • Dysphagia.
  • Dysphonia.
  • Cough.
  • Cyanosis.
  • Collapse.

Diagnostic investigation

Endoscopy

  • Intraluminal tumor.

Histopathology

  • Neoplastic cells.

Radiography

  • See thoracic radiography Radiography: thorax.
  • Extent of tumor - presence of soft tissue mass in larynx.
  • Thoracic radiographs for metastasis Lung: classic cannonball metastases - radiograph lateral  Lung: metastases - radiograph lateral .
  • Thoracic radiographs for secondary bronchopneumonia Lung: pneumonia - radiograph lateral .

Biochemistry

  • Check for feline leukemia virus infection, if lymphoma.

Confirmation of diagnosis

Discriminatory diagnostic features

  • Clinical signs.
  • History.
  • Radiography.
  • Endoscopy.

Definitive diagnostic features

  • Histopathology.

Gross autopsy findings

  • Examine entire URT and LRT to rule out other conditions.
  • Consider touch preparation and microbiological sampling of mass.
  • Examine and fix regional lymph nodes.

Histopathology findings

  • Extralaryngeal neoplasia.
  • Lymphoma - dense sheets of infiltrative lymphoid cells.
  • Squamous cell carcinoma - infiltrative cords and nest of keratinizing epithelial cells.
  • Polyp - epithelium-covered protruding mass of connective tissue with variable inflammatory component.
  • Cyst - fluid filled, thin-walled mass, perhaps containing glandular secretions.

Differential diagnosis

  • Laryngeal paralysis.
  • Laryngeal foreign body.
  • Extralaryngeal neoplasia.
  • Developmental cysts.
  • Non-neoplastic inflammatory conditions.

Treatment

Standard treatment

  • Treatment depends on biological behavior of tumor type.
  • Lymphoma - chemotherapy Chemotherapy; general principles, or radiotherapy Radiotherapy.
  • Local excision unlikely to be effective with malignant tumors. Total laryngectomy with permanent tracheostomy unlikely to be tolerated in most cats but possible.

Monitoring

  • Clinical signs.
  • Regression/recurrence of tumor.
  • Routine hematology and urinalysis if on chemotherapy.

Prevention

Outcomes

Prognosis

  • Poor; depends on histological type, location and extent of tumor.

Expected response to treatment

  • Improvement in signs.
  • Non-recurrence/regression of tumor.

Reasons for treatment failure

  • Inoperability.
  • Difficulty of surgical removal.
  • Resistance to chemotherapy.
  • Aspiration pneumonia.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Carlisle C H, Biery D N & Thrall D E (1991) Tracheal and laryngeal tumors in the dog and cat - literature review and 13 additional patients. Vet Rad 32 (5), 229-235 VetMedResource.
  • Saik J E, Toll S L, Diters R W et al (1986) Canine and feline laryngeal neoplasia a 10 year survey. JAAHA 22 (3), 359-365 VetMedResource.