Orbito‐nasal cyst in a young European short‐haired cat

Abstract

Purpose To describe a case of an orbito‐nasal cyst in a cat. Procedure An 18‐month‐old male European short‐haired cat was presented to the Ophthalmology service of the Vetsuisse Faculty, University of Zurich for a subcutaneous swelling in the medial canthal region of the right eye (OD). Ophthalmologic, ultrasound and CT examinations, and fine needle aspiration were performed. After lesion excision, the removed tissue was submitted for histopathology. CT examination was repeated 5 months after removal of the cyst. Results Ophthalmologic examination revealed a large fluctuant swelling inferonasal to OD. Despite patent lacrimal puncta, only the first few mm of the lacrimal canaliculi could be cannulated. A normal globe with moderate enophthalmos was present. Ultrasound examination showed a well‐defined lobulated cyst‐like structure in the right orbit, inferonasal and anterior to the eye. CT examination revealed extension of this lesion through the medial orbital wall into the right nasal cavity. Fine needle aspiration confirmed the cystic nature of the lesion. An orbito‐nasal cyst was diagnosed. The orbital part of the cyst was dissected from the surrounding tissue and excised from the periosteum in the medial orbital wall defect. Part of the maxillary bone was removed to allow removal of the cyst from the nasal cavity. Histologically, the cyst wall consisted of a single to multilayered, mostly cuboidal epithelium and surrounding connective tissue. Follow‐up revealed a good functional result and no recurrence 7 months after cyst removal. Conclusions Similar orbito‐nasal cystic structures were reported in dogs but not in cats.

Use of 1% polidocanol and pre‐ and post‐computed tomography for treatment of a suspected nasolacrimal duct cyst in a dog

“…Nasolacrimal duct cysts (dacryocysts) are reported infrequently in veterinary medicine . Proposed causes include congenital malformations (ie ectopic lacrimal tissue), neoplasia, or inflammation (ie local inflammation, dacryocystitis, trauma) which leads to weakening of the duct wall . It is thought that, despite the underlying cause, inflammation leads to lacrimal hypersecretion resulting in the formation of the cystic structure .…”

“…It is thought that, despite the underlying cause, inflammation leads to lacrimal hypersecretion resulting in the formation of the cystic structure . In most cases, the etiology is presumptive and based on history and clinical findings, including the presence and location of a non‐painful swelling …”

“…Assessment of nasolacrimal duct patency is important for confirming nasolacrimal duct occlusion as the cause of epiphora . Diagnostic tests range from rudimentary to advanced and include the Jones test, nasolacrimal cannulation and flushing, ultrasonography and dacryocystography with concurrent radiography or computed tomography . If a structural lesion is identified on imaging, fine needle aspiration and biopsy of the identified lesion aid in definitive diagnosis and treatment plan formulation .…”

“…Diagnostic results typically reveal a fluid‐filled soft tissue mass in the area of the nasolacrimal duct with compromised contrast flow through the affected nasolacrimal duct, viscous, blood‐tinged fluid, bistratified columnar epithelium with or without mineral deposition within the nasolacrimal duct system, or a cystic lumen lined by cuboidal to cylindrical, non‐ciliated epithelium, resembling glandular epithelium . Immunohistochemical staining for smooth muscle actin and analysis of mineral deposits (calcium carbonate in the dog and a mixture of carbonate hydroxyapatite and sodium halite in the horse) if present within the lesion may be used to increase the index of suspicion for a nasolacrimal duct cyst in cases where histopathology is inconclusive …”

“…The tissue of origin often cannot be determined radiographically and should be confirmed histologically . Bony changes associated with a cyst, if present, should not alter the smooth margin of bone and should lack malignant characteristics such as mineralization of the lesion and lysis of the bone …”