Histopathological study of the causes for failure of intrascleral prostheses in dogs and cats
Fonte: Carolina Naranjo and Richard R. Dubielzig
Feline scleral shell showing the regrowth of a diffuse iris melanoma. Note that the silicone prosthesis is still within the shell.
Objective: To characterize the histopathological causes for failure of intrascleral prosthesis placement in dogs and cats. Procedures: The Comparative Ocular Pathology Laboratory of Wisconsin database was searched to find canine and feline evisceration samples that were diagnosed with neoplasia. A second population included canine and feline scleral shells that were removed after an evisceration surgery had been performed. The causes for removal were divided into: neoplasia, corneal abnormalities, and other causes. Results: In dogs, 163 of 1985 evisceration samples (8.21%) contained a neoplasm, whereas 17 of 88 (19.31%) evisceration samples in cats contained a neoplasm. In dogs, severe corneal disease was diagnosed in 38 of 80 scleral shells (46.25%) and neoplasia was diagnosed in 31 of 80 scleral shells (38.75%). Malignant melanoma was the most frequently diagnosed tumor, in 14 of 31 scleral shells. In cats, eight of 12 scleral shells contained a tumor (66.7%), with feline diffuse iris melanoma being diagnosed most commonly (six of eight shells). Two of 12 feline scleral shells had severe corneal disease (16.7%). Epithelial downgrowth, lining the inner aspect of the fibrous tunic, was seen in 14 of 38 canine scleral shells and in two of two feline scleral shells with severe corneal disease. Conclusions: Severe corneal disease and neoplasia are the most common causes for intrascleral prosthesis failure in dogs, whereas neoplasia is the single most common cause for intrascleral prosthesis failure in cats.