¹VetAmerikan Animal Hospital, TR-34406 Kağıthane, İstanbul - TÜRKİYE
²Vetlab Veterinary Diagnostic Laboratory Services, Kadıköy, TR-34710 İstanbul - TÜRKİYE DOI : 10.9775/kvfd.2023.31363 In this report, we described the clinical, ultrasound, contrast-enhanced T2-weighted brain magnetic resonance imaging (MRI), and histopathological findings of a retinoblastoma-like tumor with brain metastasis in a 3-year-old male Border Collie. Ophthalmoscopic and ultrasonographic examination revealed leukocoria associated with a solid mass of retinal origin in the left eye. Simultaneous contrast-enhanced T2- weighted brain MRI evaluation revealed solid masses at three different locations: the first one at the levels of the suprasellar cistern, third ventricle and chiasma opticum; the second one in the medulla oblongata adjacent to the caudal cranial fossa; and the third one in the left intraocular region. Histopathological examination of the extracted mass in the globe revealed a retinoblastoma-like tumor. The patient died before receiving radiotherapy treatment. In conclusion: this report highlights the importance of early diagnosis through ophthalmoscopic and ultrasonographic examinations. Emphasizing the brain as a potential secondary metastatic site, the report underscores the critical need to create a window for timely radiotherapy. Furthermore, the recommendation is made to evaluate dogs with leukocoria during ophthalmoscopic examination for both retinoblastoma and potential brain metastasis. Keywords : Dog, Embryonal tumors with multilayered rosettes (ETMR), Ocular neoplasia, Primary neuroectodermal tumors (PNET), Retinoblastoma-like tumor