Skip to main content Skip to main menu
UF Health University of Florida
Veterinary Diagnostic Imaging College of Veterinary Medicine
LA Radiology Overview

Case reveal

Ultrasound:

  • A focal well-circumscribed lobular mass is identified between the thyroid and arytenoid cartilages on the left side of the larynx, extending into the region of the cricoarytenoideus lateralis muscle (yellow arrows). The cranial extent of the of the left arytenoid cartilage is depressed towards midline with a concave lateral margin. The mass has a mixed echogenicity with a large tissue component. The central aspect of the cranial mass has increased fluid within the tissues. A mass effect is identified dorsal to the right and left arytenoid cartilages. Thickened echogenic tissue is present peripheral and proximal to the right and left arytenoid cartilages. The left side is more affected than the right.
  • Focal areas of mineralization are identified in the muscular processes of the right and left arytenoid cartilages.

Radiograph:

  • Extending from the ventral cricopharyngeal region/the laryngeal cartilages, a smoothly margined, rounded, and soft tissue opaque mass is identified. 
  • There is a small volume of air within the cervical esophagus. 
  • The laryngeal cartilages have multifocal regions of amorphous mineralization

MRI:

  • A multilobulated well-circumscribed mixed-signal intensity laryngeal mass is identified on all sequences. This mass is most prominent on the left side of the larynx and is immediately adjacent to, or extending from the regions of lateral and rostral margins of the left arytenoid cartilage and/or left lateral cricoarytenoideus lateralis muscle. The mass is deep to the thyroid cartilage at this level. The mass continues dorsally and crosses midline. At this level extends caudally and is contacting the cricoid cartilage and the dorsal margin of the right arytenoid cartilage. The margin of the left arytenoid cartilage is focally indistinct in 2 areas along the rostral and lateral margins of the arytenoid cartilage.  The dorsal margin of the left arytenoid cartilage is depressed ventrally by the mass. The mucosa of the arytenoid cartilages is diffusely thickened. The mass has peripheral contrast enhancement with multiple small areas of enhancement within the mass.

Conclusions:

  • Laryngeal mass, consider granuloma, inspissated abscess and/or neoplasia (squamous cell carcinoma; onchocytoma or chondroma).
  • Aerophagia.
  • Laryngeal cartilage dystrophic mineralization.

Follow-up:

  • Endoscopy (performed before ultrasonographic, radiographic and MRI evaluation of the laryngeal region): A large mass was found protruding from the dorsal aspect of the larynx and compressing it ventrally. There was an ulcerated circular defect on the rostral portion of the mass lateral to the right arytenoid.
  • No additional diagnostics were performed.

A little bit more…

  • Laryngeal masses are rare in horses and may be associated with trauma, inflammatory/infectious or neoplastic etiologies. Laryngeal masses in horses can include cysts, chondromas, hemangiomas, granulomas, hematomas lymphosarcomas, squamous cell carcinomas, and papillomas (Lekeux et al.). 
  • These masses can obstruct the airway, making it difficult for horses to breathe and exercise (Lekeux et al.). 
  • Upper airway endoscopy allowed limited evaluation of the mass and MRI was most helpful for its localization due to its greater soft tissue contrast (Pekarkova et al.). The MRI characteristics of the normal larynx in horses was previously described: https://doi.org/10.1111/j.1740-8261.2009.01555.x
  • Computed tomography has been reported to be of limited value for assessing the equine larynx and pharynx because of the lack of contrast between soft tissue structures. In the presence of mass, angiography may help differentiate affected regions (Pekarkova et al.).
  • Radiographs have high sensitivity for detection of laryngeal masses but superimposition of other structures often poses some limitations (Pekarkova et al.).
  • Treatment for laryngeal masses in horses depends on the type of mass and its location. Treatments may include: antibiotic treatment, anti-inflammatory agents, surgical resection of the mass, and laser or formalin injections for cysts (Lekeux et al.).

References:

  • Koenig J, Silveira A, Chalmers H, Buenviaje G, Lillie BN. Laryngeal neuroendocrine tumour in a horse. Equine Veterinary Education. 2012 Jan;24(1):12-6.
  • Pekarkova M, Kircher PR, Konar M, Lang J, Tessier C. Magnetic resonance imaging anatomy of the normal equine larynx and pharynx. Veterinary radiology & ultrasound. 2009 Jul;50(4):392-7.
  • Lekeux P, Art T, Hodgson DR. The respiratory system: anatomy, physiology, and adaptations to exercise and training. The Athletic Horse: principles and practice of equine sports medicine. 1994:79-127.