This paper describes a small intracranial aneurysm incidentally found in a 24-month-old Nova Scotia Duck Tolling Retriever evaluated for a recent history of lethargy, fever, and cervical pain. The clinicopathological analysis revealed leukocytosis, and increased haptoglobin and C-reactive protein consistent with severe flogistic process. Nonenhanced computed tomography of the brain and cervical spine showed a diffuse encephalopathy and moderate cervical syringohydromyelia. Computed tomography angiography series of the brain showed a small saccular dilation at the joining point of the two rostral cerebral arteries consistent with a small aneurysm. Cerebrospinal fluid examination led to the final diagnosis of aseptic meningitis. The dog was discharge with a long-term corticosteroid therapy for the meningitis. At two-month follow-up evaluation, the cerebrospinal fluid examination was normal and the computed tomography of the brain showed no abnormalities except for the stable aneurysm. To our knowledge, this is the first description of a spontaneous cerebral aneurysm in dogs and serves to broaden the spectrum of cerebrovascular diseases in this species. 1. Introduction A brain aneurysm is an abnormal, outward pouching of the artery wall caused by a weakness in the wall of an artery that supplies the brain. In humans, the prevalence of this condition is about 5%. Approximately, 85% of aneurysms develop in the anterior portion of the circulation of the brain and are asymptomatic until they rupture [1–3]. Cerebral aneurysms are classified based on a number of features including etiology, size, shape, the association with the specific intracranial branch, or according to their angioarchitecture features [2, 4–6]. To date, very little is known concerning the type and incidence of variants and anomalies of the cerebrovascular system in dogs and cats [7–9]. Historically, few cases of cerebral hemorrhage in dogs were thought to be correlated to aneurysm, but their existence could not be proved [10]. To the authors knowledge, this is the first description of a spontaneous cerebral aneurysm in dogs. 2. Case Presentation A 24-month-old 22？kg intact male Nova Scotia Duck Tolling Retriever was evaluated for a recent history of lethargy, fever, and cervical pain. Medical history included another episode of cervical pain that has occurred one year before and rapidly improved with corticosteroid therapy for few days. At the time of presentation, the dog was receiving amoxicillin/clavulanic acid for 2 days (10？mg/kg PO q12). At physical examination, the dog showed
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