Diagnostic challenge: right head tilt and depression in a dog

Abstract

Section 1 Clinical history and neurological examinationA 2-year-old male neutered Boston Terrier was initially presented to the primary care clinician with an acute onset of right head tilt and depression. The neurological signs progressively worsened over the following 4 days during which time seizure-like episodes were observed.Antibiotic therapy failed to alleviate the neurological clinical signs. The dog was then admitted to the referral clinic for neurological evaluation.General physical examination by the referral veterinary neurologist was unremarkable and neurological examination confirmed the rightsided head tilt and somnolence. Blood glucose and ammonia levels were within normal limits. Magnetic resonance imaging (MRI) revealed a large cystic mass involving the fourth ventricle, cerebellum and brainstem (Figure 1). The mass was hypointense on T1-weighted and hyperintense on T2-weighted images, relative to the surrounding parenchyma. The mass was surrounded by a hyperintense rim on post-contrast images. The clinical signs did not resolve with intra-venous mannitol and diazepam and given the cost and questionable outcome, euthanasia was elected. The dog was subsequently submitted for necropsy. Gross pathologyThe most significant macroscopic postmortem finding was a 22 × 15 × 15 mm mass within and expanding the fourth ventricle, extending into the mesencephalic aqueduct and compressing the cerebellum and brainstem ( Figure 1A). The mass was bilobed, well-demarcated, noninfiltrative and white to beige with a moderately firm outer rim and granular to friable centre. There was moderate, diffuse symmetrical lateral ventricular dilation with slight attenuation of the adjacent neural parenchyma. Diagnostic challengeFormulate differential diagnoses from the clinical history, gross pathology ( Figure 1A) and MRI findings ( Figure 1B); then turn the page.

Anaplasic Ependymoma in a Dog

“…Histopatologicamente, são densamente celulares, bastante vascularizados e possuem como característica a formação de rosetas e pseudorrosetas [8]. Os principais diagnósticos diferenciais para massas em quarto ventrículo são papiloma do plexo coróide, ependimoma, meduloblastoma, cisto epidermóide ou cisto dermóide [2]. No presente relato, o diagnóstico definitivo foi obtido através da necropsia e exame histopatológico, nos quais diagnosticou-se que a massa no terceiro ventrículo correspondia a um ependimoma anaplásico.…”