Dacryops (lacrimal cyst) in three young labrador retrievers.

This case series constitutes a report of dacryops in multiple Labrador retrievers and the use of smooth-muscle actin immunostaining to confirm the lacrimal duct origins of the cyst wall. Three Labrador retrievers were presented with a history of a slowly enlarging mass adjacent to the left medial canthus. Ultrasonography of the masses revealed they were each spherical, thin-walled cystic structures. Aspiration cytology was performed in two cases revealing mixed inflammation and absence of detectable microorganisms. Dacryocystorhinography of the left nasolacrimal system performed in two cases revealed a normal nasolacrimal system that was closely associated, but not communicating with, the cystic mass in both cases. Surgical excision of all cysts was curative. Histopathology and positive immunohistochemical staining for smooth-muscle actin confirmed a diagnosis of dacryops in all cases.