Lacrimal bone agenesis in a dog.

A 20-month-old neutered male dachshund dog was referred because of a 10-week history of swelling close to the medial canthus of the left eye. Recurrence of the lesion and cytological appearance of the fluid content were suggestive of inflammation. Computed tomography revealed a triangular-shaped bone defect in the skull deep to the lesion. Computed tomography dacryocystography demonstrated contrast medium pooling within the maxillary recess and nasal cavity rather than filling the lacrimal duct. Lacrimal bone agenesis was diagnosed. Key clinical message: Congenital skull including lacrimal bone agenesis may be responsible for swelling of the medial canthus of the eye and computed tomography dacryocystography is helpful in making a diagnosis.