The neuronal ceroid lipofuscinoses (NCLs) are hereditary neurodegenerative diseases characterized by seizures and progressive cognitive decline, motor impairment, and vision loss accompanied by accumulation of autofluorescent lysosomal storage bodies in the central nervous system and elsewhere in the body. Mutations in at least 14 genes underlie the various forms of NCL. One of these genes, CLN8, encodes an intrinsic membrane protein of unknown function that appears to be localized primarily to the endoplasmic reticulum. Most CLN8 mutations in people result in a form of NCL with a late infantile onset and relatively rapid progression. A mixed breed dog with Australian Shepherd and Blue Heeler ancestry developed neurological signs characteristic of NCL starting at about 8months of age. The signs became progressively worse and the dog was euthanized at 21months of age due to seizures of increasing frequency and severity. Postmortem examination of the brain and retinas identified massive accumulations of intracellular autofluorescent inclusions characteristic of the NCLs. Whole genome sequencing of DNA from this dog identified a CLN8:c.585G>A transition that predicts a CLN8:p.Trp195* nonsense mutation. This mutation appears to be rare in both ancestral breeds. All of our 133 archived DNA samples from Blue Heelers, and 1481 of our 1488 archived Australian Shepherd DNA samples tested homozygous for the reference CLN8:c.585G allele. Four of the Australian Shepherd samples tested heterozygous and 3 tested homozygous for the mutant CLN8:c.585A allele. All 3 dogs homozygous for the A allele exhibited clinical signs of NCL and in 2 of them NCL was confirmed by postmortem evaluation of brain tissue. The occurrence of confirmed NCL in 3 of 4 CLN8:c.585A homozygous dogs, plus the occurrence of clinical signs consistent with NCL in the fourth homozygote strongly suggests that this rare truncating mutation causes NCL. Identification of this NCL-causing mutation provides the opportunity for identifying dogs that can be used to establish a canine model for the CLN8 disease (also known as late infantile variant or late infantile CLN8 disease).

Cervical spine tumors, whether primary bone tumors or metastatic tumors, are rare. The possibility of tumors existing must be considered in the differential diagnosis of patients with persistent neck pain, with or without neurologic symptoms, particularly in those with significant pain at night. The clinical presentation is extremely variable, though a history of malignancy should always raise the concern for recurrence. The evaluation and diagnostic assessment includes a thorough physical examination. Radiographic imaging is usually initiated with plain radiographs and additional advanced imaging obtained as indicated. Using appropriate biopsy principles and techniques, tissue is obtained for histologic determination of the suspected lesion before surgical intervention. Treatment options are extremely variable and depend on many factors, including tumor type, location, and patient preference. Treatment warrants a multidisciplinary approach from experienced physicians and is most successfully accomplished in referral centers. Oncologic staging using the Enneking staging system, followed by surgical staging using the Weinstein, Boriani, Biagini system, will aid in the accurate characterization of the tumor load, maximize surgical goals, assure use of appropriate terminology, and provide optimal communication among treatment centers regarding tumor characteristics, treatment efforts, and results.

BackgroundThe dynamic component of disc‐associated cervical spondylomyelopathy (DA‐CSM) currently is evaluated using traction magnetic resonance imaging (MRI), which does not assess changes in flexion and extension of the cervical vertebral column. In humans with cervical spondylotic myelopathy, kinematic MRI is used to identify dynamic compressions.Hypothesis/ObjectivesTo evaluate the feasibility and utility of kMRI in Doberman Pinschers with DA‐CSM using a novel positioning device. We hypothesized that kMRI would identify compressive lesions not observed with neutral positioning and change the dimensions of the spinal cord and cervical vertebral canal.AnimalsNine client‐owned Doberman Pinschers with DA‐CSM.MethodsProspective study. After standard MR imaging of the cervical spine confirmed DA‐CSM, dogs were placed on a positioning device to allow imaging in flexion and extension. Morphologic and morphometric assessments were compared between neutral, flexion, and extension images.ResultsFlexion was associated with improvement or resolution of spinal cord compression in 4/9 patients, whereas extension caused worsening of compressions in 6/9 patients. Extension identified 6 new compressive lesions and was significantly associated with dorsal and ventral compression at C5‐C6 (P = .021) and C6‐C7 (P = .031). A significant decrease in spinal cord height occurred at C6‐C7 from neutral to extension (P = .003) and in vertebral canal height at C5‐C6 and C6‐C7 from neutral to extension (P = .011 and .017, respectively).Conclusions and clinical importanceOur results suggest that kMRI is feasible and provides additional information beyond what is observed with neutral imaging, primarily when using extension views, in dogs with DA‐CSM.

Osseous-associated cervical spondylomyelopathy in dogs is characterized by both static and dynamic spinal cord compression; however, standard MRI methods only assess static compression. In humans with cervical spondylotic myelopathy, kinematic MRI is commonly used to diagnose dynamic spinal cord compressions. The purpose of this prospective, analytical study was to evaluate kinematic MRI as a method for characterizing the dynamic component of osseous-associated cervical spondylomyelopathy in dogs. We hypothesized that kinematic MRI would allow visualization of spinal cord compressions that were not identified with standard imaging. Twelve client-owned dogs with osseous-associated cervical spondylomyelopathy were enrolled. After standard MRI confirmed a diagnosis of osseous-associated cervical spondylomyelopathy, a positioning device was used to perform additional MRI sequences with the cervical vertebral column flexed and extended. Morphologic and morphometric (spinal cord height, intervertebral disc width, spinal cord width, vertebral canal height, and spinal cord area) assessments were recorded for images acquired with neutral, flexion, and extension imaging. A total of 25 compressions were seen with neutral positioning, while extension identified 32 compressions. There was a significant association between extension positioning and presence of a compressive lesion at C4-C5 (p = 0.02). Extension was also associated with a change in the most severe site of compression in four out of 12 (33%) dogs. None of the patients deteriorated neurologically after kinematic imaging. We concluded that kinematic MRI is a feasible method for evaluating dogs with osseous-associated cervical spondylomyelopathy, and can reveal new compressions not seen with neutral positioning.

Published information regarding canine vertebral column mast cell tumors (MCTs) is limited. The objectives of this study were to report clinical and advanced imaging findings for a group of dogs with confirmed spinal MCT. Inclusion criteria for this retrospective case series were dogs with spinal magnetic resonance imaging (MRI) or computed tomography (CT) scans and a histological diagnosis of spinal MCT. Clinical, imaging, treatment, and outcome data were recorded. Four dogs met inclusion criteria. One dog had primary spinal MCT and three dogs had metastatic spinal MCT. All four dogs presented for paraspinal hyperesthesia and subacute progressive or acute myelopathy. All CT and MRI lesions were extradural. Two cases exhibited distinct masses in the epidural space. In one case, an epidural tumor invaded from the paravertebral musculature. One case exhibited polyostotic lesions indistinguishable from multiple myeloma by MRI. One dog with a primary epidural low-grade MCT remains clinically normal 4 years postoperatively, following adjunctive lomustine. An epidural high-grade MCT, metastatic from a cutaneous tumor, recurred within 2 months of surgery despite adjunctive vinblastine. Two high-grade cases with concurrent visceral involvement were euthanized immediately after imaging. In dogs, MCT should be considered as a differential diagnosis for a progressive painful myelopathy and CT or MRI evidence of an extradural spinal lesion (epidural, paravertebral, or polyostotic). While more often associated with cutaneous or disseminated disease, MCT may also occur as a primary tumor of the epidural space in dogs.