A case of squamous cell carcinoma with infiltrative growth in a cat

Purpose: To describe an extensively infiltrating ocular squamous cell carcinoma in a domestic cat. Material/Methods: A 10-year-old, female spayed domestic short haired cat (DSH) was referred to ophthalmology clinic Centro Veterinario Argo – Ancona – Italy, for exophthalmus, pain and blepharospasm in the left eye. Ophthalmological examination showed marked blepharospasm, severe pain after digital pressure and conjunctival chemosis of left eye, while menace response and fundus were not possible to evaluate. Right eye revealed positive menace response, direct PLR and normal fundus. Due to the impossibility of completely evaluation of the left eye, ocular ultrasonography was performed, showing a loss of intraocular structures replaced by a hyperechoic mass. Cat was FIV and FeLV negative and an aspirate of left retromandibular lymphnode was submitted for cytological evaluation. Symptomatic therapy for pain was given before proceeding to left eye exenteration. Results: Macroscopic evaluation of left eye, after formalin fixation, showed complete loss of normal architecture which was substituted by a grayish, irregular, proliferative tissue. Histologically, a highly infiltrative squamous cell carcinoma (SCC) invaded and replaced the normal ocular structures. The neoplasia extended only focally to the conjunctiva at the base of the nictitans membrane and infiltrated extensively into the orbital muscle. Discussion: To the authors best knowledge this is the first report of ocular SCC in an Italian tricolor cat. Absence of involvement of the eyelid and focal extension to conjunctiva and the base of nictitans membrane suggest that neoplasia development did not start from the conjunctival or palpebral epithelium but most likely from the limbus. Support/Interest disclosure: None.