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 Het al(2014)Epithelial inclusion cysts of the frontal bones in three horses.Equine Vet Educ26(7), 357-361 VetMedResource.
  • Barakzai S (2011)Clinical refresher: equine sinus cyst.UK Vet16(2), 4-6 VetMedResource.
  • Woodford N S & Lane J G (2006)Long-term retrospective study of 52 horses with sinunasal cysts.Equine Vet J38(3), 198-202 PubMed.
  • Perkins J & Barakzai S (2005)The equine paranasal sinuses - Part 4.UK Vet10(5), 5-8 Scribd.
  • Beard W L & Hardy J (2001)Diagnosis of conditions of the paranasal sinuses in the horse.Equine Vet Educ13(5), 265-273 VetMedResource.
  • Gilroy B Jet al(1999 )Paranasal sinus cyst as a cause of stridor in a standard bred colt.Can Vet J40(1), 49-51 PubMed.
  • Ruggles A Jet al(1993 )Endoscopic examination and treatment of paranasal sinus disease in 16 horses.Vet Surg22(6), 508-514 PubMed.
  • Trotter G W (1993 )Paranasal sinuses.Vet Clin North Am Equine Pract9(1), 153-169 PubMed.
  • Freemanet al(1990)A large frontonasal bone flap for sinus surgery in the horse.Vet Surg19(2), 122-130 PubMed.
  • Beard W Let al(1990)Bilateral congenital cysts in the frontal sinuses of a horse.JAVMA196(3), 453-453 PubMed.
  • Lane J Get al(1987)Equine paranasal sinus cysts: a report of 15 cases.Equine Vet J19(6),537-544 PubMed.
  • Lane J Get al(1987)Radiographic examination of the facial, nasal, and paranasal sinus regions of the horse - 1. Indications and procedures in 235 cases.Equine Vet J19(5), 466-473 PubMed.
  • Boles C (1979)Abnormalities of the upper respiratory tract.Vet Clin North Am Large Annim Pract1(1), 89-111 PubMed.
  • Cannon J H et al (1976)Diagnosis and surgical treatment of cyst-like lesions of the equine paranasal sinuses.JAVMA169(6), 610-613 PubMed.