Retinoblastoma in a dog.

Michael Nork // Publications // Jun 01 1997

PubMed ID: 9194728

Author(s): Syed NA, Nork TM, Poulsen GL, Riis RC, George C, Albert DM. Retinoblastoma in a dog. Arch Ophthalmol. 1997 Jun;115(6):758-63. PMID 9194728

Journal: Archives Of Ophthalmology (Chicago, Ill. : 1960), Volume 115, Issue 6, Jun 1997

OBJECTIVE To describe and classify a retinal tumor found in a dog that histologically resembles human retinoblastoma and to discuss the molecular mechanisms of retinal oncogenesis.

METHODS A dog eye with a retinal tumor was examined histologically. Studies including immunocytochemical analysis for retinal S-antigen and glial fibrillary acidic protein, enzyme histochemical analysis for carbonic anhydrase, and nick-end DNA labeling were used to characterize the tumor. Normal retina from another dog and other tumors from dogs, including 2 ciliary body medulloepitheliomas and a brain medulloepithelioma, were examined as controls.

RESULTS The retinal tumor disclosed characteristics typical of human retinoblastoma, including Flexner-Wintersteiner rosettes. It showed strong immunoreactivity with S-antigen and glial fibrillary acidic protein. Carbonic anhydrase activity also could be shown in the tumor. Apoptosis was found to be the predominant method of cell death as shown by nick-end DNA labeling. In contrast to the other tumors examined, this tumor contained areas with retinal photoreceptor and glial differentiation.

CONCLUSIONS The histopathologic findings and differential staining characteristics in this retinal tumor are compatible with retinoblastoma, making this, to our knowledge, the first documented case of spontaneous retinoblastoma in an animal.