Case history: Three horses were presented with facial swelling and epiphora.
Clinical findings: All horses had facial swellings and radiographic findings consistent with exostosis at the lacrimomaxillary suture, and ipsilateral epiphora. Positive contrast dacryocystorhinography demonstrated that the site of obstruction of the nasolacrimal duct was located where the duct traverses the lacrimomaxillary suture.
Diagnosis: Lacrimomaxillary suture exostosis.
Clinical relevance: Lacrimomaxillary suture exostosis should be considered as a differential diagnosis in cases of epiphora in horses. Dacryocystorhinography, preferably retrograde and normograde, may be used as an aid to diagnosis.