Journal of Feline Medicine and Surgery (2010) 12, 179e182doi:10.1016/j.jfms.2009.10.003

CASE REPORTSpinal cord compression in a cat due to vertebralangiomatosis

David Schur, Nathalie Rademacher Dr Med Vet, DECVDI*, Sunil Vasanjee BVSc, MS, DACVS,Leslie McLaughlin DVM, DACVP*, Lorrie Gaschen DVM, Dr Med Habil, PhD, DECVDI

Section of Diagnostic Imaging,Louisiana State University, Schoolof Veterinary Medicine, BatonRouge, LA 70803, USA

*Corresponding author. E-mail: nradem

1098-612X/09/020179+04 $36.00/0

A 1-year-old cat was presented with general discomfort but no neurologicdeficits on physical examination. An extradural spinal cord compression at thelevel of T10-11 and T11-12 was evident on myelography and computedtomography examination. Hemilaminectomy was performed to decompress thespinal cord. Histopathology of the abnormal pedicle and lamina revealedvertebral angiomatosis. This rare vascular malformation was the cause of thespinal cord compression in this cat. It is seen in cats less than 2 years of age andaffected the thoracic spine in all four previously reported cases.

Date accepted: 19 October 2009 Published by Elsevier Ltd on behalf of ESFM and AAFP.

A1-year-old neutered male domestic shorthaircat was presented with a 6-week history ofpain in the axillary and lumbar regions and

general discomfort. Dexamethasone injections admin-istered by the referring veterinarian resolved the clin-ical signs temporarily, but they reoccurred 9 dayslater. Physical examination showed pain upon palpa-tion of the spine and on ventroflexion of the neck.Serological tests for toxoplasmosis and feline leuke-mia virus/feline immunodeficiency virus were nega-tive. No abnormality was noted on complete bloodcount, chemistry panel, urinalysis and cerebrospinalfluid analysis. Anesthesia was induced using a combi-nation of medetomidine (Dormitor; Pfizer, New York,USA) and ketamine (Vetaket; Lloyd Inc, Iowa, USA)and maintained with isoflurane (IsoFlo; Abbott Labo-ratories, Illinois, USA). All diagnostic procedureswere undertaken during the same anesthetic episode,while the surgery was performed a day later using thesame anesthetic protocol. No abnormal events ortrends were reported during this period. The cat ap-peared stable during the whole time.

Survey radiographs of the spine showed an ill-de-fined sclerosis and new bone formation associatedwith the vertebral pedicle and body at the 11th tho-racic vertebra on the left side in the ventrodorsalview (Fig 1). The cranial and caudal articular facetof T11 appeared mildly irregular on this side. A mye-logram was performed by placing a 22 gauge spinal

acher@vetmed.lsu.edu

needle into the ventral subarachnoid space at L5/6and injecting 0.25 ml/kg of 240 mgI/ml Iohexol (Om-nipaque, General Electric (GE) Healthcare, Princeton,New Jersey (NJ)). A narrowing of the contrast columnwas observed ventrally at the level of T11-12 and dor-sally within the vertebral body of T11 in the lateralview. On the ventrodorsal view, marked displacementof the left contrast column toward the midline withinthe vertebral body of T11 was noted (Fig 2). An extra-dural, focal left-sided spinal cord compression at T11was diagnosed. Differential diagnoses included verte-bral new bone formation due to old trauma, disc ex-trusion, cartilaginous exostoses, bone abscess,neoplasia, granuloma, old hematoma or migratingforeign body. In order to better define the lesion andto aid surgical planning, a post-myelographic com-puted tomography (CT) was performed.

Continuous transverse images with a slice thicknessof 2 mm and a bone algorithm were acquired from T9through T13 using a single slice helical scanner (PickerPQ 5000, Universal Medical Systems, Ohio, USA). Athinning of the contrast column with deviation ofthe spinal cord to the right side within the body ofT11 was observed (Fig 3A). Marked thickening ofthe left pedicle of T11 with new bone formation in-volving the entire length of the vertebral body wasnoted. Some of its margins were irregular while otherswere smooth (Fig 3B). The new bone formation wasaccentuated laterally, but also involved the mediallamina and, therefore, resulted in a narrowing of thevertebral canal diameter and displacement of the

Published by Elsevier Ltd on behalf of ESFM and AAFP.

Fig 1. Survey ventrodorsal view of the thoracolumbarspine: Notice the ill-defined and irregular new boneformation on the left lateral side of T11 (arrows).

Fig 2. Oblique ventrodorsal myelographic image of thethoracolumbar area: Note the marked deviation of the spinalcord to the right side with narrowing of the spinal cordwithin the vertebral body of T11.

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spinal cord to the right side. Hyperdense material wasseen within the intervertebral foramen and the verte-bral canal at T11-T12 with an attenuation value of 680Hounsfield units. In the normal adjacent bone, an at-tenuation value of 800 HU was measured. Consider-ing the changes seen on CT, the lesion wasconsidered to be most likely due to bony callus as a re-sult of an old trauma or chronic infection. Malignantneoplasia was considered less likely due to the ageof the animal and the lack of lysis. Congenital benignvascular malformation was not excluded as manyskeletal neoplasms in cats are proliferative.

The following day, a left-sided hemilaminectomyincluding the articular processes of T10-11 and T11-12was performed in order to explore and decompressthe spinal cord. The surface of the cortex of the lamina

Fig 3. (A) and (B). Transverse CT images (bone window) ofT11. The images were obtained following intrathecalinjection of contrast medium. Note the markedly thickenedlamina on the left side in comparison to the right with irreg-ular new bone formation laterally. There is also hyperdensematerial within the vertebral canal causing marked devia-tion of the spinal cord to the right. The lamina was submit-ted for histopathology and found to be reactive bone.

181Vertebral angiomatosis in a cat

and body of the vertebra was irregular and appearedto have proliferative new bone. The bone being burredaway seemed to be of normal density. The hemilami-nectomy site spanned the entire compressive region.Evaluation of the epidural space revealed the absenceof epidural fat and the spinal cord was deviated to theright side. An autogenous fat graft obtained from thedorsal subcutaneous tissue was placed at the hemila-minectomy site followed by routine closure.

The lamina and several small fragments of bone weresubmitted for cytology, histopathology and culture/sensitivity. Cytological impression smears were of lowcellularity, consisting of erythrocytes and few nucle-ated cells, including well-differentiated osteoblastsand osteoclasts, showing a poor degree of cellular pres-ervation. No neutrophils or other inflammatory cellswere observed. Histopathology revealed multifocal an-giomas consisting of benign proliferations of well-differentiated, small caliber blood vessels throughoutthe medullary cavity, consistent with vertebralangiomatosis.

Medetomidine was reversed at the end of surgerywith 0.0025 mg of atipamezole (Antisedan; Pfizer,New York USA). Postoperatively the cat was slow torecover from anesthesia with an uneventful extuba-tion period. Three hours after surgery the cat experi-enced cardiorespiratory arrest. Cardiac function was

re-established. After 2 h of manual ventilation, thecat did not regain spontaneous ventilation; the ownerselected euthanasia without pursuing necropsy.

Several studies and case reports of specific diseaseprocesses affecting the spinal cord of cats have beenpublished, including feline infectious peritonitis(FIP), lymphoma, intervertebral disk disease and ver-tebral column neoplasia as well as ischemia or infarctand trauma.1e6 A large retrospective study of neuro-logical diseases in cats using archived central nervoustissue identified inflammatory disease as themost common cause, mainly due to FIP.7 This is inaccordance with a retrospective study looking at theoccurrence of spinal cord disease in cats identifiedon post-mortem examination and identified FIP, lym-phoma, and neoplasia of the vertebral column second-arily affecting the spinal cord as the most commoncauses.3 However, a more recent retrospective studyinvestigating cats with clinical spinal disease wheremagnetic resonance imaging (MRI) was performedshowed neoplastic disease to be the most commoncause of spinal cord diseases.8 Another report statesthat neoplasia is the second most common cause of ex-tradural, extramedullary compression and often af-fects the vertebral body in cats.9,10 Extradurallymphoma would be the most likely possibility inyoung animals and is often associated with feline leu-kemia virus, but it is still rare and often is character-ized by bone lysis as opposed to new bonegrowth.4,6,10 Osteosarcoma is the most common pri-mary vertebral bone tumor in cats but is rare ata young age.11 Diagnosis of spinal cord disease ismade based on physical and neurological examina-tion, clinical signs as well as spinal radiography, mye-lography, CT and MRI.5 Cerebrospinal fluid analysiscan be useful in determining if infection is present,but the results are often non-specific with non-infec-tious spinal cord disease.2,5 In the cat in this report,where physical and laboratory examinations wereinconclusive, diagnostic imaging was critical to thediagnosis of spinal cord compression.

Vertebral angiomatosis has also been reported withclinical and radiographic signs very similar to this pa-tient in one case report.12 Vertebral angiomatosis isconsidered a rare vascular malformation, character-ized by the formation of multiple angiomas whichare non-neoplastic tumors that form blood vessels.Histologically these lesions are benign proliferationsof blood vessels of undetermined origin with well-dif-ferentiated vascular walls.13

Three descriptions are available in the literature, de-scribing the radiographic and histologic appearance ofthe disease in four cats12,13 and the radiographic andCT finding in one cat. Each of the reported cats was be-tween 1 and 2 years old, had a history of pain, parapa-resis and ataxia. In all reported cases, the lesions werelocalized to the thoracic vertebral spine. Of the fourpreviously reported cases, two underwent surgical de-compression with no reported clinical signs a fewmonths after surgery. Unfortunately, the cat in this

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case report died a few hours after surgery and necropsywas declined by the owners. However, the authors be-lieve that the death was unrelated to the vertebral an-giomatosis. To the author’s knowledge, this is thesecond case report describing the CT findings in a catwith vertebral angiomatosis.

Other causes of new bone formation include boneabscess or infection, migrating foreign body, or con-genital defect.9,10

In young cats presented with back pain and parapa-resis and new bone formation in the thoracic spine,the list of differential diagnoses should include benignbut invasive diseases such as vertebral angiomatosis.Previously published reports describe a favorableprognosis after surgical management.

References1. Kathmann I, Cizinauskas S, Rytz U, Lang J, Jaggy A.

Spontaneous lumbar intervertebral disc protrusion incats: literature review and case presentations. J FelineMed Surg 2000; 2: 207e12.

2. Knipe MF, Vernau KM, Hornof WJ, LeCouteur RA. Inter-vertebral disc extrusion in six cats. J Feline Med Surg2001; 3: 161e8.

3. Marioni-Henry K, Vite CH, Newton AL, Van Winkle TJ.Prevalence of diseases of the spinal cord of cats. J VetIntern Med 2004; 18: 851e8.

4. Munana KR, Olby NJ, Sharp NJ, Skeen TM. Interverte-bral disk disease in 10 cats. J Am Anim Hosp Assoc2001; 37: 384e9.

5. Scott, HW, McLaughlin, R. Fractures and disorders of thespine. In: Feline orthopedics, Mauson; London, 2007.

6. Withrow SJ, Vail DM. Tumors of the nervous system.Withrow and MacEwen’s small clinical oncology 4thedn. St Louis: Saunders (Elsevier), 2006: 659e85.

7. Bradshaw JM, Pearson GR, Gruffydd-Jones TJ. A retro-spective study of 286 cases of neurological disorders ofthe cat. J Comp Pathol 2004; 131: 112e20.

8. Goncalves R, Platt SR, Llabres-Diaz FJ, et al. Clinical andmagnetic resonance imaging findings in 92 cats withclinical signs of spinal cord disease. J Feline Med Surg2009; 11: 53e9.

9. Lang J, Seiler G. Neuroradiologie. Atlas und Lehrbuchder Kleintierneurologie 2nd edn. Stuttgart: Schlutersche,2005: 87e151.

10. LeCouteur RA, Grandy JL. Diseases of the spinal cord.In: Ettinger SJ, Feldman EC, eds. Textbook of veterinaryinternal medicine 6th edn. Philadelphia: Saunders, 2005:864e9.

11. Withrow SJ, Vail DM. Tumors of the skeletal system.Withrow and MacEwen’s small clinical oncology 4thedn. St Louis: Saunders (Elsevier), 2006: 567e8.

12. Kloc 2nd PA, Scrivani PV, Barr SC, et al. Vertebral angio-matosis in a cat. Vet Radiol Ultrasound 2001; 42: 42e5.

13. Wells MY, Weisbrode SE. Vascular malformations in thethoracic vertebrae of three cats. Vet Pathol 1987; 24:360e1.

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