Background <p>Cerebral hemangioma is a recognized cause of acute onset of epileptic seizures with interictal neurological abnormalities in dogs, although the number of cases reported is limited. Hemangiomas can affect dogs of all age groups, but there is an increasing risk with age, peaking at nine years.</p> Case presentation <p>This case report describes a 5-month-old female Chow Chow dog with an acute onset of epileptic seizures and interictal neurological deficits indicative of a right forebrain lesion due to a cerebral hemangioma and associated hemorrhage. Initially, extracranial causes were excluded, and magnetic resonance imaging of the head was performed, revealing a large well-delineated hemorrhagic mixed intra- and extra axial lobular mass in the right frontal lobe, generalized ventriculomegaly, and two intraventricular smaller, well-defined cyst-like structures in the right cerebellopontine angle and fourth ventricle. The dog was euthanized due to the severity of neurological deficits combined with imaging findings, suggesting a poor prognosis. Post-mortem gross examination, histopathology, and immunohistochemistry identified the larger structure as a hemangioma accompanied by extensive hemorrhage. The significant hemorrhage likely explained the acute onset of neurological signs. It is probable that the hemangioma might have remained subclinical, had this hemorrhage not occurred. The smaller cyst-like structures were identified as multilocular ependymal diverticula originating from the fourth ventricle.</p> Conclusions <p>This case report underlines the importance of considering cerebral hemangiomas accompanied by acute hemorrhage as a possible differential diagnosis in cases with an acute onset of epileptic cluster seizures with accompanying interictal neurological signs, here found in a juvenile dog.</p>