Equis ISSN 2398-2977

Paranasal sinus: cyst

Contributor(s): Steve Adair, Vetstream Ltd


  • Developmental disorder of the maxillary sinus in foals; also seen in mature horses - single or multiple loculated cavities in maxillary or frontal sinus; cavity has an epithelial lining and contains fluid.
  • Cause: abnormal tooth root development; ?congenital, submucosal hemorrhage.
  • Signs: facial distortion, nasal discharge.
  • Diagnosis: respiratory system exam, drainage by trephination, radiography, endoscopy.
  • Treatment: cyst removal, emergency tracheostomy.



  • Abnormal tooth root development.
  • ?congenital, submucosal hemorrhage.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gunnarsdottir H et al (2014) Epithelial inclusion cysts of the frontal bones in three horses. Equine Vet Educ 26 (7), 357-361 VetMedResource.
  • Barakzai S (2011) Clinical refresher: equine sinus cyst. UK Vet 16 (2), 4-6 VetMedResource.
  • Woodford N S & Lane J G (2006) Long-term retrospective study of 52 horses with sinunasal cysts. Equine Vet J 38 (3), 198-202 PubMed.
  • Perkins J & Barakzai S (2005) The equine paranasal sinuses - Part 4. UK Vet 10 (5), 5-8 Scribd.
  • Beard W L & Hardy J (2001) Diagnosis of conditions of the paranasal sinuses in the horse. Equine Vet Educ 13 (5), 265-273 VetMedResource.
  • Gilroy B J et al (1999 ) Paranasal sinus cyst as a cause of stridor in a standard bred colt. Can Vet J 40 (1), 49-51 PubMed.
  • Ruggles A J et al (1993) Endoscopic examination and treatment of paranasal sinus disease in 16 horses. Vet Surg 22 (6), 508-514 PubMed.
  • Trotter G W (1993) Paranasal sinuses. Vet Clin North Am Equine Pract (1), 153-169 PubMed.
  • Freeman et al (1990) A large frontonasal bone flap for sinus surgery in the horse. Vet Surg 19 (2), 122-130 PubMed.
  • Beard W L et al (1990) Bilateral congenital cysts in the frontal sinuses of a horse. JAVMA 196 (3), 453-453 PubMed.
  • Lane J G et al (1987) Equine paranasal sinus cysts: a report of 15 cases. Equine Vet J 19 (6), 537-544 PubMed.
  • Lane J G et al (1987) Radiographic examination of the facial, nasal, and paranasal sinus regions of the horse - 1. Indications and procedures in 235 cases. Equine Vet J 19 (5), 466-473 PubMed.
  • Boles C (1979) Abnormalities of the upper respiratory tract. Vet Clin North Am Large Annim Pract (1), 89-111 PubMed.
  • Cannon J H et al (1976) Diagnosis and surgical treatment of cyst-like lesions of the equine paranasal sinuses. JAVMA 169 (6), 610-613 PubMed.