1. Labrador Retriever, m, castrated, 7y. Case of the month June 2006

2. Acute head tilt and circling to the right. Slightly reduced right sided pupillary reflex, other cranial nerves without abnormalities. Ears unremarkable. Treatment with 1 mg/kg Cortisone; no improvement; after 5 days acute worsening: Unable to walk, reduced menace response on the right. Skull radiographs and examination of the ears under anesthesia were unremarkable. History

3. Referral to Neurology Division of the Vetsuisse Faculty University Berne Results of neurologic exam Head tilt to the right Tetraparesis Vestibular strabism Bilaterally reduced proprioception of hindlimbs  MRI of the head

4. FSE T2-weighting transverse T: trachea dorsal right Level of optic chiasmLevel of bullae (b) b b T TT

5. dorsal right Level of bullae (III)Level of bullae (II) TT FSE T2-weighting transverse

6. FLAIR (CSF suppression) dor rostral right rostral

7. FE 3D T1 MPR dorsal 1mm slice thickness plain+ Cplain+ C rostral right

8. Contrast enhanced, fat suppressed SE T1-weighting transverse Level of optic chiasmLevel of orbita

9. findings ?

10. Findings (1) Multiple intra- (yellow rings) and extracranial (white rings), mostly nodular lesions, hyperintense in T2 and FLAIR; contrast enhancing.

11. Findings (2) One of the lesions (in the right cerebellar peduncle; arrow) was surrounded by a not enhancing, in T2 and FLAIR diffuse hyperintense area, consistent with perifocal brain edema (arrow heads).

12. Interpretation There are multiple lesions within the brain and the musculature of the head including the tongue. The contrast uptake indicates break down of the blood/brain (blood/tissue resp.) barrier. Most lesions are rounded, some could be confluent. One of them is surrounded by diffuse brain edema. These findings are typical of metastases. Final diagnosis The muscle lesions were biopsied under ultrasonographic guidance and turned out to be metastases from an hemangiosarcoma.

13. Comment Hemangiosarcomas occur in the spleen, liver, heart base and lungs of older dogs. They usually metastasize into the lungs, but spine and brain-metastases have also been described. Due to its excellent soft tissue contrast, MRI allows the detection of even small metastases. The application of contrast agent increases the sensitivity of the examination. Metastases can be diagnosed by their disseminated, rounded appearance with strong contrast enhancement. Hemangiosarcoma metastases appear bright in all fluid sensitive sequences.