Sometimes, the same group of Schwann cells and their concentrically arranged processes surrounded two or three axons individually wrapped in myelin sheaths. Sural nerve biopsy was performed at the level of the left lateral malleolus. Neurological examination at the age of 9 years revealed slight motor deficit in the lower limbs, particularly in the feet, and generalized hyporeflexia. Genetic studies are of value not only for diagnosing these diseases, but also for better understanding the molecular mielinz that result in the clinical symptoms. These clinical and electrophysiological features are suggestive of hereditary motor-sensory neuropathy.

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Roselene Ecco Acta Scientiae Veterinariae, They occur especially in the peripheral nerves of the brachial plexus, and may occasionally invade and compress the spinal cord. Initial clinical diagnosis is challenging, since the main clinical sign is a progressive claudication, whose origin, neurogenic or musculoskeletal, is not usually defined. The objective of this report is to describe clinical, ultrasonographic, tomographic and histopathological findings in a peripheral nerve sheath tumor in the brachial plexus of a dog, to assist clinicians making an early diagnosis, so patients can attain longer survival.

Case: A 9-year-old, male, intact, Dachshund was presented to a veterinary neurologist with a history of lameness of the right forelimb onset five months ago. The condition progressed slowly to right hemiparesis and proprioceptive ataxia. Clini- cal and neurological findings included right hemiparesis, proprioceptive ataxia and proprioceptive deficits with decreased flexor reflex and marked atrophy of the right forelimb.

Palpation of the right axilla allowed identification of a firm 1 x 3 cm mass, with intense hyperesthesia. Ultrasound examination of the right axilla revealed hypoechoic tubular mass of 1. Once the animal presented signs of ataxia and paresis to the right pelvic limb, it was indicated a com- puted tomography to observe a possible compression of the spinal cord. An expansive formation was observed in the right brachial plexus between C6-C7 vertebral bodies with isodense characteristic, ring-shaped, with dimensions of 3.

Due to poor prognosis and poor quality of life, euthanasia was elected. The gross changes of the spinal cord were characterized by a firm nodule with irregular surface at the brachial plexus with invasion and com- pression of C7-C8 spinal cord segment. The microscopic evaluation allowed a diagnosis of malignant sheath nerve tumor. Discussion: Peripheral nerve sheath tumors PNST arise from Schwann cells, perineurial fibroblastos or a combination of both cell types that surround axons of peripheral nerves.

The diagnosis of PNST is more common in middle-aged to older dogs, of medium to large breeds, as observed in the animal of this report. Palpation of a mass in the axillary region is possible in only Ultrasound examination is fast and sensitive for identifying PNST while cross sec- tional imaging, such as computed tomography are recommended to define the extent of disease and therapeutic planning.

However, definitive diagnosis can only be achieved from histopathological examination. The prognosis for animals with PNST is poor, especially when it is associated with invasion of the spinal canal. Early diagnosis, from a detailed clinical examination and imaging exams, must be associated with an aggressive surgical intervention or debulking surgery followed by radiotherapy, in order to improve prognosis, quality of life and survival of these patients.

Keywords: dogs, oncology, neurology, neoplasm, peripheral nerve. Martins [bernardodcmartins hotmail. Martins, G. Martins, R. Horta, et al. Acta Scientiae Veterinariae. Os exames Figura 2. O exame ultrasso- da bainha de mielina.

A prolife- incipiente no perineuro. A B Figura 3. Hematoxilina e eosina. Podem ser benignas ou [2,7]. Ataxia proprioceptiva e nove meses ou proximal um a 7,5 meses [2]. Neste caso, necrose neuronal. Spinal Neoplasm in Small Animals. A retrospective evaluation of 51 cases of peripheral nerve sheath tumors in the dog.

Journal of American Animal Hospital Association. Ultrasound- guided fine needle aspiration in the diagnosis of peripheral nerve sheath tumors in 4 dogs. Canadian Veterinary Journal. Metronomic therapy with cyclophosphamide and piroxicam effectively delas tumor recurrence in dogs with incompletely resected soft tissue sarcomas.

Journal of Veterinary Internal Medicine. Magnetic resonance imaging characteristics of peripheral nerve sheath tumors of the canine brachial plexus in 18 dogs. Neurologic conditions causing lameness in companion animals. Tumors of the Nervous System. In: Withrow S. Philadelphia: Saunders, pp. Magnetic reso- nance imaging and ultrasonography in the diagnosis of a malignant peripheral nerve sheath tumor in a dog. Ultrasonographic evaluation of brachial plexus tumors in five dogs.

Computed tomography of masses of the brachial plexus and contributing nerve in dogs. A canine peripheral nerve sheath tumor including peripheral nerve fibers. The Journal of Veterinary Medical Science. Arquivo Brasileiro de Medicina Veterinaria e Zootecnia. Feline peripheral nerve sheath tumors: histologic, immunohistochemical, and clinicopathologic correlation 59 tumors in 53 cats.

Veterinary Pathology. CR 83 www.



No axon damage was observed Figures 12 and bainha de mielina. Atrophy of the legs due to wasting of the peroneal muscles can result in a stork leg or inverted champagne bottle appearance. These clinical and electrophysiological features are suggestive of hereditary motor-sensory neuropathy. All the axons observed were surrounded by a thin myelin sheath and concentrically arranged bainha de mielina processes of Schwann cells forming onion-bulbs. The classification of hereditary motor-sensory neuropathies depends on the clinical and laboratory features. Genetic studies are of value not only for diagnosing these diseases, but also for better understanding the molecular events that result in the clinical symptoms. There was increased conjunctive tissue with thickened bands of collagen fibers in the endoneurium.


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