Oronasal blastomycosis in a golden retriever

Blastomycosis is one of the most common systemic fungal infections in dogs in North America Pulmonary manifestations are most common; localized disease is rare. A case of localized oronasal blastomycosis mimicking oral neoplasia is described. Long-term therapy with itraconazole resulted in clinical cure.     

Cerebral ganglioneuroblastoma in a golden retriever dog

An 8-month-old Golden Retriever dog was euthanatized because of a large cerebral mass extending from the right frontal lobe to the thalamus that was composed of both mature and immature neuronal cells. The better differentiated cells had abundant eosinophilic cytoplasm with prominent Nissl substance and were generally positive for neurofilament and variably positive for synaptophysin. The generally smaller and less-differentiated cells were infrequently positive for proliferating cell nuclear antigen and were negative for any neuronal and glial markers. No apparent glial differentiation of the immature tumor cells was detected. Based on morphologic and immunohistochemical features, the diagnosis of cerebral ganglioneuroblastoma was made. This neoplasm is very rare in all species, especially in the central nervous system, and has never been reported previously in this site in a dog.     

Multifocal osteoma cutis in a golden retriever

A 10-year-old, spayed female, obese golden retriever, presented for immune-mediated thrombocytopenia, was successfully managed with the administration of vincristine and prednisone. However, 6 mo after discontinuing corticosteroid therapy because of suspected iatrogenic hyperglucocorticoidism, the patient was presented with multiple, firm, bilaterally symmetric, dermal masses composed histologically of differentiated cortical bone.     

Renal nephroblastoma in a 3-month-old golden retriever

Nephrectomy was performed in a 3-month-old intact female golden retriever dog for a renal nephroblastoma. The dog has remained disease-free for 19 months with nephrectomy alone. The adoption of human Wilms’ tumor grading criteria may be useful in determining clinical stage, adjuvant treatment options, and prognosis in this rare disease.     

Uterine carcinoma in a 10-month-old golden retriever

A 10-month-old golden retriever was presented for investigation of reduced appetite, occasional vomiting and general dullness. Abdominal radiography demonstrated a large mid-abdominal soft tissue mass. Exploratory laparotomy identified a uterine mass, which was removed surgically. Histopathology confirmed uterine adenocarcinoma. Adjunctive chemotherapy with epirubicin was performed. The dog remained clinically normal without evidence of metastatic disease 24 months after surgery. Canine uterine adenocarcinoma is an extremely rare tumour and, as far as the authors are aware, this is the youngest reported case to date.     

Dermoid sinus in a Rhodesian ridgeback

A dermoid sinus was identified in a Rhodesian ridgeback dog. Diagnosis was by physical examination, contrast radiography, gross and microscopic evaluations. Surgical resection of the lesion was curative.     

Peripheral hypomyelinization in two golden retriever littermates

Peripheral hypomyelinization was found in 2 Golden Retriever littermates that had pelvic limb ataxia, depressed postural reactions, and depressed segmental reflexes. Diagnostic findings included infrequent denervation potentials, reduced or absent evoked potentials, and markedly diminished motor nerve conduction velocities. Light and electron microscopy of peripheral nerves revealed fewer than normal myelinated axons, myelinated sheaths inappropriately thin for the caliber of the fiber, poor myelin compaction, greater than normal numbers of Schwann cell nuclei, many Schwann cells with voluminous cytoplasm, and greater than normal amount of perineural collagen. Findings were compatible with a peripheral hypomyelinization process; a defect in Schwann cell function was suspected.     

Idiopathic Horner's syndrome in the golden retriever

A prospective study was made of cases of idiopathic Horner's syndrome in dogs referred to the author. Over a six-year period the condition was recorded in 62 golden retrievers. Examination suggested that the lesions affected the preganglionic neuron.     

Dermoid sinus removal in a rhodesian ridgeback dog

A three year old Rhodesian Ridgeback dog with a history of a small draining tract in the dorsal cervical area, was found to have a dermoid sinus on surgical exploration. The affected tissue was removed and histopathology done. The sinus is an inherited condition in this breed of dog, with surgical correction and neutering of affected individuals the treatments of choice to reduce the incidence of the dermoid sinus condition in the next generation.     

Congenital hypomyelinating polyneuropathy in two golden retriever littermates

Serial peripheral nerve biopsies from two golden retriever littermates with chronic neurologic disease were taken for morphologic and morphometric evaluation. Teased nerve preparations were difficult to interpret due to the lightness of myelin staining. Light and electron microscopic findings were characterized by the following: reduced number of myelinated axons, presence of myelinated sheaths inappropriately thin for the caliber of the fiber, poor myelin compaction, increased numbers of Schwann cell nuclei, increased concentration of neurofilaments in myelinated axons, many Schwann cells with voluminous cytoplasm, and increased perineurial collagen. Onion bulb formation was not seen. In contrast to control data, a poor correlation was seen between numbers of myelin lamellae (ML) and axonal circumference (AC). The frequency distribution of ML ranged from 5 to 55 lamellae in affected animals (mean, 28 lamellae) compared to 20 to 140 lamellae in controls (mean, 66 lamellae). The ML/AC ratio was significantly reduced (P less than 0.001) in nerves of affected dogs. Morphometric results indicated that fibers of all calibers were hypomyelinated.     

Atherosclerosis associated with vasculopathic lesions in a golden retriever with hypercholesterolemia

A 2-year-old neutered male golden retriever dog presented for lameness secondary to ulcerations of multiple digital paw pads was diagnosed with vasculitis and hypercholesterolemia. Despite treatment, ischemic necrosis progressed to include all distal extremities and the dog eventually expired due to myocardial infarction secondary to severe atherosclerosis. The rapid demise and the dermatologic lesions may have been secondary to cholesterol embolism syndrome which has never before been reported in a dog.     

Genetic management of Dutch golden retriever dogs with a simulation tool

Excessive inbreeding rates and small effective population sizes are an important problem in many populations of dogs. Proper genetic management of these populations can decrease the problem, and several measures are available. However, the effectiveness of these measures is not clear beforehand. Therefore, a simulation model was developed to test measures that aim to decrease the rate of inbreeding. The simulation program was used to evaluate inbreeding restriction measures in the Dutch golden retriever dog population. This population consisted of approximately 600 dams and 150 sires that produce 300 litters each year. The five most popular sires sire approximately 25% of the litters in a year. Simulations show that the small number of popular sires and their high contribution to the next generation are the main determinants of the inbreeding rates. Restricting breeding to animals with a low average relatedness to all other animals in the population was the most effective measure and decreased the rate of inbreeding per generation from 0.41 to 0.12%. Minimizing co‐ancestry of parents was not effective in the long run, but decreased variation in inbreeding rates. Restricting the number of litters per sire generally decreased the generation interval because sires were replaced more quickly, once they met their restriction. In some instances, this lead to an increase in inbreeding rates because the next generations were more related. The simulation tool proved to be a powerful and educational tool for deciding which breeding restrictions to apply, and can be effective in different breeds and species as well.