Spinal Neoplasm in Dogs

Abstract

Background: Various diseases can cause spinal cord disorders in dogs including neoplasia of the nervous system, which are more common in mature and older animals. Some breeds, as brachycephalics, are more predisposed for certain types of tumors. Spinal neoplasia can be categorized as primary or secondary tumors, and still can be grouped in extradural, intradural/extramedullary or intramedullary. The aim of this study was to investigate the signalment, neurological syndrome, type and source of the mass, presence of metastases, and clinical outcomes in 28 dogs diagnosed with spinal tumors.Materials, Methods & Results: This study included 28 dogs, and in 20 cases, spinal neoplasia was confirmed by necropsy, biopsy, histopathology, and immunohistochemistry. In the other eight animals, the presumptive diagnosis was based on clinical and neurological signs and by observing changes in plain radiographs of the spine, chest radiographs, and myelography. The location of the lesion was established as cervical, cervicothoracic, thoracolumbar, or lumbosacral, and the lesion was determined to be multifocal when clinical signs appeared in more than one location. Spinal cord injury was additionally classified as unilateral, bilateral, symmetrical, or asymmetrical. The following complementary examinations were performed based on the clinical suspicion, indications, and availability of the owner: complete blood count, serum biochemical profile, urinalysis, spinal radiography, cerebrospinal fluid analysis (CSF), myelography, abdominal ultrasound, thoracic X-ray to determine metastases, and Computed Tomography. CSF was collected and analyzed in seven animals, and pleocytosis with a predominance of lymphocytes was found in two cases. Decompression and exploratory surgeries were performed in six dogs to confirm the suspected diagnosis and collect tissues for histopathology. The final diagnosis was made by histopathological examination of the tissue obtained by excisional biopsy or necropsy after the death of the animal or euthanasia. In eight cases, the neoplasia type could not be confirmed as the owner did not provide consent to perform exploratory surgery or necropsy. The dogs most affected were poodles (17.85%) and boxers (17.85%), between the ages of 5 and 10 years, and 67.85% of the cases were female dogs. The thoracolumbar region was the most affected (50%). Metastatic spinal tumors predominated; especially those originating in the mammary gland (38.46%) and on the skin (34.61%), and among the primary neoplasms, meningiomas predominated. The clinical course in relation to the onset of symptoms of neurological dysfunction, until death or euthanasia, ranged from 1-170 days, with an average 42 days of survival.Discussion: The results differ from previous studies, in which the number of male and female dogs with neoplasms in the CNS was the same, as in the present study female dogs were more affected. Unlike other studies, metastatic spinal tumors predominated. After the diagnosis, the survival was short and this may be due to the fact that most dogs in this study already had more than one system affected, and consequently showed significant changes related to systemic metastases during the onset of the neurological symptoms. The surgical treatment presented variable results, and the results observed after surgical resection of neoplasms vary due to the location in relation to the spinal cord, neoplasm type, severity of the clinical signs, and possibility of removal along with margin without causing spinal instability. In dogs with spinal disorders, the veterinary practitioner should suspect cancer, especially if there is a history of excision of neoplasms in other systems.

Surgical management of a metastatic vertebral tumour originating from a mammary adenocarcinoma in a dog

“…A report by Egenvall et al (2007) revealed an incidence rate of 9% for malignant bone tumours localised to the vertebrae in Swedish dogs. Moreover, various diseases, including neoplasia, cause spinal cord disorders in dogs, resulting in symptoms, such as ataxia, paraparesis, paraplegia, tetraparesis, and tetraplegia (Bagley 2010;Valentim et al 2016). The range and severity of these symptoms also depend on several factors: the spinal region affected, localisation with respect to the spinal cord, cell type, malignancy, and compression rate (Seguin et al 2000;North and Banks 2009).…”

“…Malignant tumours can spread throughout the body. Although the lungs are the most common site for the distant metastasis of canine mammary cancer, metastasis to the skeletal system, including the vertebral bone, occasionally occurs (Cooley and Waters 1998;Valentim et al 2016). Specifically, metastatic neoplasms account for 65% of spinal tumours in dogs, predominantly originating from the mammary gland (Valentim et al 2016).…”

“…Notably, primary tumours can be difficult to identify in cases where the initial clinical manifestation results from metastatic lesions (Cooley and Waters 1998). There are many types of symptoms related to the bone tumour location, such as neurological signs (e.g., ataxia, paresis, and paralysis) if the spinal cord is affected (Valentim et al 2016).…”

Carcinoma with Vertebral Column Metastasis in Two Dogs

“…A ocorrência de metástases para a coluna vertebral já foi relatada anteriormente em casos de carcinomas mamários, pancreáticos e prostáticos de cães [12] e no epitélio transicional da uretra de cães e felinos [3,11], na maioria das vezes cursando com infiltração na músculatura e nas vértebras adjacentes. Em ambos os casos deste relato notou-se acentuada deformidade das estruturas ósseas acometidas pela metástase, esse fato não é claro nestes relatos, visto que muitos deles apresentam casos de tumores intradurais, epidurais e/ou na medula espinhal, sem associação com a estrutura óssea vertebral [11,17].…”

“…Os sinais neurológicos foram mais acentuados no paciente do caso 2, em que houve compressão de segmentos medulares torácicos, levando a lesões importantes de neurônio motor superior. Relatam-se casos de meningiomas no canal medular de cães, promovendo compressão entre T2 e T4, com sinais clínicos similares aos observados, como paralisia bilateral de membros pélvicos, apresentando boa resposta após o tratamento cirúrgico [17]. Aponta-se que esses tumores eram passíveis de remoção cirúrgica, diferenciando em muito da metástase observada no paciente supramencionado.…”