Equis ISSN 2398-2977

Ethmoid: hematoma

Contributor(s): Patrick Colahan, Paddy Dixon, Vetstream Ltd, Graham Munroe


  • An expanding lesion on the ethmoid turbinate or adjacent paranasal sinuses that causes a low-grade intermittent nasal hemorrhage.
  • Cause: unknown; not neoplasia.
  • Signs: epistaxis, respiratory noise; rarely neurologic signs.
  • Diagnosis: endoscopy, radiography, standing head CT.
  • Treatment: surgical excision, laser therapy, chemical ablation.
  • Prognosis: good following surgical treatment; 25% recur.
Print off the Owner factsheet on Epistaxis - nosebleed to give to your clients.



  • Unknown.
  • Postulated causes include chronic infection, repeated trauma, congenital disorder and neoplasia.



  • Angiomatous mass of unknown origin on the mucosa of the ethmoid turbinates, usually on the nasal side, and occasionally within the paranasal sinuses.
  • Spontaneously bleeds → serosanguinous nasal discharge, usually unilateral.
  • Progressive growth into one or both nasal passages, paranasal sinuses and nasopharynx obstruction and destruction of adjacent tissue.
  • In severe cases, the growing mass deforms the profile of the frontonasal bones and can obstruct the corresponding nasal passage, and even erode into the bone of the calvarium or infraorbital canal.
  • Hematoma on ethmoid → periodic rupture of mucosal capsule and hemorrhage into ethmoidal sinuses and caudal maxillary sinus → epistaxis.
  • Obstructed sinus drainage → mucous retention → secondary sinusitis.
  • Obstructed airflow → dyspnea.


  • Usually a slowly progressive enlargement.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Tremaine W H (2013) Progressive ethmoid hematoma. Equine Vet Educ 25 (10), 508-511.
  • Tessier C et al (2013) Magnetic resonance imaging features of sinonasal disorders in horses. Vet Radiol Ultrasound 54 (1), 54-60 WileyOnline.
  • Texor J A et al (2013) Results of computed tomography in horses with ethmoid hematoma: 16 cases (1993-2005). J Am Vet Med Assoc 240 (11), 1338-1344 AVMA Journals.
  • Smith L J & Perkins J (2009) Standing surgical removal of a progressive ethmoidal haematoma invading the sphenopalatine sinuses in a horse. Equine Vet Educ 21 (11), 577-581 VetMedResource.
  • Tremaine W J (2009) The diagnosis and treatment of progressive ethmoidal haematomas. Equine Vet Educ 21 (11), 582-583.
  • Archer D (2008) Differential diagnosis of epistaxis in the horse. In Pract 30 (1), 20-29 VetMedResource.
  • Marriott M R et al (1999) Treatment of progressive ethmoidal haematoma using intralesional injection of formalin in three horses. Aust Vet J 77 (6), 371-373 PubMed.
  • Rothaug P G & Tulleners E P (1999) Neodymium:yttrium-aluminium-garnet laser-assisted excision of progressive ethmoid hematomas in horses: 20 cases (1986-1996). J Am Vet Med Assoc 214 (7), 1037-1041. 
  • Tremaine W H, Clarke C J & Dixon P M (1999) Histopathological findings in equine sinonasal disorders. Equine Vet J 31 (4), 296-303 PubMed.
  • Schumacher Jet al (1998) Transendoscopic chemical ablation of progressive ethmoidal hematomas in standing horses. Vet Surg 27, 175-181 PubMed.
  • Bell B T, Baker G J, Abbott L C, Foreman J H & Kneller S K (1995) The macroscopic vascular anatomy of the equine ethmoidal area. Anat Histol Embryol 24 (1), 39-45 PubMed.
  • Greet T R (1992) Outcome of treatment in 23 horses with progressive ethmoidal hematoma. Equine Vet J 24, 468-471 PubMed.