A hyperintense region of the spinal cord > 6 times the length of L2 on T2-weighted imaging might be a characteristic MRI finding of PM. In some dogs, such MRI findings were observed before PM was clinically diagnosed. Progressive myelomalacia may thus be diagnosable at the early stage through MRI and CSF examination before signs of PM develop.

Objective. We previously reported that the Val58Ile polymorphism of the leukocyte cell-derived chemotaxin 2 gene (LECT2) is associated with the severity of rheumatoid arthritis (RA). To define the role of LECT2 in inflammatory arthritides, we investigated the development of collagen antibody-induced arthritis (CAIA) in LECT2-deficient (LECT2 ؊/؊ ) mice.Methods. CAIA was induced in mice by administering anti-type II collagen antibodies followed by lipopolysaccharide. Daily assessment of hind paw swelling was used to monitor the development of arthritis. The histopathologic features and expression of inflammatory cytokines were also analyzed. We confirmed the role of LECT2 by introducing a LECT2 expression vector into LECT2 ؊/؊ mice, using a hydrodynamic gene transfer method.Results. Arthritis in LECT2 ؊/؊ mice was significantly exacerbated compared with that in wild-type (WT) controls. Histopathologic assessment of the tarsal joints showed that inflammation and erosion of cartilage and bone in LECT2 ؊/؊ mice were more severe than that in controls. Interleukin-1␤ (IL-1␤), IL-6, and certain chemokines were present at significantly higher levels in the arthritic hind paws of LECT2 ؊/؊ mice. In contrast, the amount of LECT2 in the serum and locally in the hind paws was higher in arthritic WT mice. Finally, hydrodynamic gene transfer experiments revealed that the severity of arthritis was reduced by the systemic expression of exogenous mouse LECT2 protein in LECT2 ؊/؊ mice.Conclusion. These results strongly suggest that LECT2 directly suppresses the development of CAIA. Manipulation of LECT2 might provide a rationale for novel therapeutic approaches to the treatment of inflammatory arthritides such as RA.

Arachnoid cysts of the quadrigeminal cisterna are infratentorial cystic lesions located between the collicular plate and the incisural notch of the tentorium. We report here five cases of quadrigeminal cisterna arachnoid cysts in dogs. In this study, four of the five dogs were male, three showed signs of seizures, and one dog was over 10 years of age. In two of the dogs, cysts were discovered incidentally. In previous reports, most intracranial arachnoid cysts were located in the quadrigeminal cisterna. The presence of cysts should be considered in toy breeds presenting for seizures or ataxia.

Two young Miniature Dachshunds were presented with abnormal gait. Magnetic resonance imaging showed, hydrocephalus with expanding fourth ventricle, and syringohydromyelia in the cervical spinal cord. These dogs underwent ventricle-peritoneal shunting, after which hydrocephalus, syringohydromyelia, and their clinical signs, improved.

Comprehensive Veterinary Clinical Studies,4) Veterinary Pathology, 5) Veterinary Physiology and 6) Preventive Veterinary Medicine and Animal Health, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-8510, Japan (Received 17 August 2006/Accepted 22 February 2007 ABSTRACT. A 10-year-old female mongrel cat with back pain was brought to the Nihon University Animal Medical Center. Palpation demonstrated a mass in the back region. Radiography revealed partial destruction of the processus spinosus and the arch of the T8 and T9 vertebrae. On magnetic resonance imaging, the mass was found to have compressed the spinal cord and extended to the outside of the spinal canal. We performed extirpation of the mass, and confirmed that it arose from the spinal canal. Histopathologically, the mass was a malignant peripheral nerve sheath tumor. KEY WORDS: feline, malignant peripheral nerve sheath tumor, MRI.J. Vet. Med. Sci. 69(6): 683-686, 2007 There is considerable confusion concerning the nomenclature of tumors deriving from the peripheral nerve sheath. Histologically, such tumors are classified into categories of benign peripheral nerve sheath tumors (schwannoma and neurofibroma) and malignant peripheral nerve sheath tumors (malignant schwannoma and neurofibrosarcoma) [8].There have been relatively few studies on feline peripheral nerve sheath tumors arising from the spinal canal, and malignant cases of this tumor are even rarer [1,8,9,19]. We encountered a cat with a malignant peripheral nerve sheath tumor arising from the spinal canal. We evaluated the clinical signs, radiography and magnetic resonance imaging (MRI) findings, surgery, and postoperative course.A 10-year-old female mongrel cat, weighing 2.14 kg, with back pain was brought to the Nihon University Animal Medical Center. The cat had been unhealthy with anorexia and constipation for 1 month, and was taken to a local veterinarian. The cat had suffered from back pain for 1 week. A mass was detected in the region of the back, and the cat was referred to our hospital for diagnosis and treatment.On initial examination, the body temperature was 40.3°C, and the heart and respiratory rates were 212/min and 40/ min, respectively. Hematological examination demonstrated slight increases in liver enzyme levels (alanine aminotransferase, 156 U/L; aspartate aminotransferase, 116 U/ L). Neurologically, the cat could walk, and all postural reactions were within the normal ranges. Spinal reflexes and deep pain were normal in both the thoracic and pelvic limbs. The cranial nerves were normal. Radiography revealed partial destruction of the T8 vertebral processus spinosus on the caudal side, T9 vertebral processus spinosus on the cranial side and T9 vertebral arch, between which hyperlucency was observed (Fig. 1).MRI (FlexArt, Toshiba, Tokyo, 1.5T) demonstrated a mass, measuring about 2.5-3 cm, on the back of the T8-9 vertebrae. T1-weighted imaging (TR=500 msec, TE=15 msec, FA 90°, NAQ 1) of the mas...