Malignant ocular teratoid medulloepithelioma in two cats.

Medulloepithelioma is a type of rare primitive neuroectodermal tumour. Most medulloepitheliomas are intraocular and they have been most frequently reported in horses and dogs. A single feline case has been reported but the teratoid form has not been previously reported in cats. Two cats presented with rapidly expanding intraocular masses and ophthalmic examination revealed vascularized uveal tumours extending into the anterior chamber and vitreous chamber. Following enucleation, histopathological examination of each case revealed a focally extensive infiltrative neoplasm that replaced the uveal tract, with retinal detachment and scleral vascular invasion. Rosettes, medullary tubes and heterotopic tissue were present. During follow-up periods of 3.4 and 8.8 years, no evidence of orbital recurrence or metastasis was found in either cat. To the best of our knowledge, these are the first case reports of teratoid medulloepithelioma in cats. Although the risk of metastasis cannot be excluded, as in other species, these findings support enucleation as a curative intervention.