Spinal epidural arteriovenous fistula in 3 cats

Three young adult cats with intermittent spinal hyperesthesia and paraparesis and diagnosed with spinal epidural arteriovenous fistula are described. In all 3 cases, magnetic resonance imaging (MRI) showed focal dilatation of the veins in the epidural space of the thoracic spinal cord, whereas computed tomography angiography (CTA) showed dilatation and enhancement from the intercostal vein to the azygos vein at the same site in the arterial phase. Dorsal laminectomy and occlusion of the interarcuate branches running across the dorsal aspect of the spinal cord were performed in all 3 cats to decompress the spinal cord, which resulted in a remission of clinical signs and no recurrence during 14 to 40 months of follow‐up after surgery in all cases.

Surgical treatment of middle ear cholesteatoma using an oral approach in 2 dogs

Middle ear cholesteatoma is caused by the formation of epidermoid cysts that result in distention and enlargement of the tympanic bulla with subsequent destruction of surrounding tissues. We report treatment of middle ear cholesteatoma in 2 dogs, via an oral surgical approach. Abnormal tympanic bulla contents and the wall compressing the pharynx were successfully removed in both cases. Computed tomography imaging, surgical findings, and histopathology results were consistent with middle ear cholesteatoma in both cases. The outcomes in both cases suggest that an oral surgical approach may be an alternative treatment for middle ear cholesteatoma in dogs. Key clinical message: Despite the limited number of cases described herein, our report indicates that the direct oral approach for canine cholesteatoma may be and alternative approach.

A canine case of malignant melanoma carrying a KIT c.1725_1733del mutation treated with toceranib: a case report and in vitro analysis

Background

Canine malignant melanoma is highly aggressive and generally chemoresistant. Toceranib is a kinase inhibitor drug that inhibits several tyrosine kinases including the proto-oncogene receptor tyrosine kinase KIT. Although canine malignant melanoma cells often express KIT, a therapeutic effect for toceranib has yet to be reported for this tumor, with only a small number of patients studied to date. This is a case report of a dog with malignant melanoma that experienced a transient response to toceranib. Furthermore, the KIT expressed in the tumor of this case was examined using molecular analysis.

Case presentation

A Shiba Inu dog presented with a gingival malignant melanoma extending into surrounding structures with metastasis to a submandibular lymph node. The dog was treated with toceranib (Palladia®; 2.6–2.9 mg/kg, orally, every other day) alone. Improvement of tumor-associated clinical signs (e.g., halitosis, tumor hemorrhage, trismus, and facial edema) with reduced size of the metastatic lymph node was observed on Day 15. The gingival tumor and associated masses in the masseter and pterygoid muscles decreased in size by Day 29 of treatment. Toceranib treatment was terminated on Day 43 due to disease progression and the dog died on Day 54. The tumor of this dog had a novel deletion mutation c.1725_1733del within KIT and the mutation caused ligand-independent phosphorylation of KIT, which was suppressed by toceranib. This mutation was considered to be an oncogenic driver mutation in the tumor of this dog, thereby explaining the anti-tumor activity of toceranib.

Conclusions

This is the first report that presents a canine case of malignant melanoma that responded to toceranib therapy. KIT encoded by KIT harboring a mutation c.1725_1733del is a potential therapeutic target for toceranib in canine malignant melanoma. Further investigation of the KIT mutation status and toceranib therapy in canine malignant melanoma will need to be undertaken.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02864-3.

Evaluation of outcomes and radiation complications in 65 cats with nasal tumours treated with palliative hypofractionated radiotherapy

Feline nasal tumours (NTs) are locally invasive and occasionally metastasise to distant sites. Although palliative hypofractionated radiotherapy (HRT) is used, its efficacy and long-term complications have not been adequately evaluated. The purpose of this study was to evaluate the efficacy of HRT in treating feline malignant NTs, including monitoring improvement in clinical signs, acute and late complications, and prognosis. The medical records of 65 cats with malignant NTs treated with HRT were included. Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method. The log-rank test and Cox proportional hazard model were used to evaluate factors that influenced OS and PFS. Clinical signs improved in 86.2% of cats following radiotherapy. Acute complications were observed in 58.5% of cats but were manageable and acceptable. Among late complications, cataract was most frequently observed (20.5%), and atrophy of the entire eyeball and osteochondroma at the irradiation site were each observed in two cats. The median OS and PFS in 65 cats were 432 days and 229 days, respectively. No significant difference between OS of cats with nasal lymphoma and that of cats with other tumours was observed. Despite some limitations due to the retrospective nature of the study, palliative HRT for feline NTs can be considered a useful treatment option because of the high incidence of improvement and more favourable prognosis, although it may be preferable not to use the hypofractionated regimen in young cats with lymphoma that are expected to survive for a long period.

Efficacy of hypofractionated radiotherapy for nasal tumours in 38 dogs (2005-2008)

OBJECTIVES

To evaluate the efficacy of hypofractionated radiotherapy for canine nasal tumours, including the improvement in clinical signs, rate of complications and assessment of prognostic factors.

METHODS

Medical records of 38 dogs with malignant nasal tumours were reviewed, and those treated with a weekly schedule of hypofractionated radiotherapy were included in the study. Acute and late side effects were defined as complications noted either within 1 month or after 6 months of irradiation, respectively. Progression-free interval and overall survival were calculated using the Kaplan-Meier method. Log-rank test and Cox proportional hazard model were also performed.

RESULTS

Clinical signs improved in 30 of 36 dogs. Acute complications were seen in 28 of 36 dogs and were considered manageable. Late complications were observed in 17 of 30 dogs that survived 6 months or longer, but severe side effects were not observed. The median progression-free interval and overall survival was 245 days (95% CI: 127-512 days) and 512 days (95% CI: 203-820 days), respectively. Age, breed and presence of dyspnoea were negatively correlated with overall survival.

CLINICAL SIGNIFICANCE

These results suggest that hypofractionated radiotherapy could be a viable option for the treatment of nasal tumours in dogs that are not candidates for conventional multi-fractionated radiotherapy.

Long-term survival in a dog with anaplastic oligodendroglioma treated with radiation therapy and CCNU

A 9 year-old, neutered, male French Bulldog showing cluster seizures was diagnosed with a glioma in the right piriform cortex by MRI. Hypofractionated radiation therapy (RT) was performed using a linear accelerator. Although the lesion had involuted significantly at 2 months after RT, recurrence was observed at 4 months after RT. Chemotherapy was started using CCNU (60 mg/m(2) every 6-9 weeks) and was continued for one year. Follow-up MRI revealed involution of the lesion and the intervals of CCNU were increased to every 9-14 weeks. Two years after the first presentation, the dog suffered status epilepticus, followed by deficits of left sided postural reaction with cognitive dysfunction. The dog died on day 910, and histopathological diagnosis confirmed anaplastic oligodendroglioma.

MEASUREMENT OF INTERTHALAMIC ADHESION THICKNESS AS A CRITERIA FOR BRAIN ATROPHY IN DOGS WITH AND WITHOUT COGNITIVE DYSFUNCTION (DEMENTIA)

The criteria for brain atrophy in dogs have not yet been established, because of wide variation in the morphology of the ventricles and sulci of the brain depending on the breed and size. In this study, we examined the thickness of the interthalamic adhesion in a transverse magnetic resonance image to investigate normal, to examine the correlation with age, body weight, and breed, and to assess whether measurement would be a useful indicator of brain atrophy. The animals used in this study were of various breeds and weight, and had no identifiable intracranial lesion. They were divided into two groups: a normal group (0.6-15-year-old, n = 66) and a demented aging group (12-18-year-old, n = 12). The interthalamic adhesion thickness in both T1- and T2-weighted transverse images were measured in all dogs. The interthalamic adhesion thickness in the normal and demented groups was 6.79 +/- 0.70 and 3.82 +/- 0.79 mm, respectively. The interthalamic adhesion thickness in the demented group was significantly smaller. In an analysis of the correlation of interthalamic adhesion thickness with age and weight in normal dogs, significant negative and positive correlation was recognized, respectively. However, the strength of these correlations was low. These results suggest that interthalamic adhesion thickness may be a good parameter for evaluating brain atrophy in dogs with cognitive dysfunction.