Pituitary tumour causing neurological and endocrine disturbances in a dog

A seven-year-old Labrador Retriever with behavioural change, mental depression, lethargy, abdominal enlargement and small testes was found to have bilateral adrenal hyperplasia secondary to an ACTH-secreting pituitary tumour which encroached on the hypothalamus and thalamus. Additional hormonal abnormalities detected were hypothyroidism, deficiencies of gonadotrophins and testosterone, and impaired growth hormone response to insulin infusion.     

Metastatic aortic body tumour causing neck pain in a dog

An aortic body tumour in an 11-year-old male Jack Russell terrier with acute onset neck pain is described. Clinical signs were related to a metastatic lesion present in the spinal column and involving the vertebral body of the fifth cervical vertebra. Radiographic and post mortem findings are described including histopathologi-cal features of the tumour and ultrastructural observations.     

Multilobular tumour of the caudal cranium causing severe cerebral and cerebellar compression in a dog

Multilobular tumour of bone (MTB) is an uncommon tumour and is usually located in the skull. A 13-year-old mixed breed dog was presented with a two-week history of progressively worsening vestibular dysfunction and cognitive abnormalities; it appeared demented and showed asymmetric ataxia and hypermetria of all limbs. The owner opted to have the animal euthanised. Necropsy revealed a large mass occupying the right occipital, parietal and temporal bones, severely compressing the cerebellum and the right occipital lobe. Histologically, it was characterised by the presence of multiple lobules containing osteoid or cartilage and separated by fibrous septae, features typical of MTB. Lung metastases were evident. To our knowledge, this is the first report of an MTB causing both severe cerebral and cerebellar compression and the second detailed report of an MTB of the occipital bone. MTB should be included in the differential diagnosis of bone tumours as well as in cases with central vestibular disease.     

Intrapericardial neuroendocrine tumour in a dog

An 11-year-old neutered male Border Terrier presented for pericardiectomy after a nine-month history of tricavitary effusion, dyspnoea and lethargy. Transthoracic echocardiography revealed a fluid-filled structure at the heart base, starting at the mid-right ventricle and extending to the middle of the right atrium. Almost complete compression of the right atrium and the cranial vena cava was noted. Thoracic computed tomography revealed a heterogeneously enhancing and poorly marginated mass within the cranial aspect of the pericardium. A median sternotomy and subtotal pericardiectomy were performed. A non-distinct fluid-filled structure within the pericardium adhered to the epicardium was visualised. The structure was removed via marsupialisation along with extirpation of enlarged sternal lymph nodes. Histopathological examination of the sternal lymph nodes revealed expansile, well-demarcated, unencapsulated nodules of neoplastic cells consistent with a neuroendocrine tumour suspected to be thyroid in origin. After surgery, intractable pleural effusion resulted in euthanasia. Intrapericardial ectopic thyroid tumours are rarely reported in animals. The location of the mass and unusual presentation may have made it challenging for echocardiography to identify this neoplasia. Thoracic computed tomography at an earlier stage may have identified the neoplasia and potentially allowed for surgical intervention.     

Intracranial meningioma causing internal ophthalmoparesis in a dog

A 10-year-old, spayed female, Irish water spaniel was presented with a 2-week history of anisocoria characterized by mydriasis of the right eye compared to the left eye in ambient light. Ophthalmic and neurological examinations, combined with pharmacological testing, identified a disease process affecting the right parasympathetic nucleus of cranial nerve 3 (CN III) and/or the parasympathetic component of CN III. Magnetic resonance imaging (MRI) identified a mass involving the right midbrain and extending caudally to the rostral border of the medulla oblongata. The dog became comatose within 12 h following MRI and was euthanized. Histopathology identified the intracranial mass as a meningioma.     

Neutrophilic leucocytosis in a dog with a rectal tumour

A nine-year-old cocker spaniel was presented with a three-year history of intermittent haematochezia and a palpable rectal mass. Routine haematological examination revealed a marked mature neutrophilia (86.04 x 10(9) neutrophils/litre). A friable mass in the middle portion of the rectum was detected on colonoscopy. Histopathological examination of mucosal pinch biopsies collected from the mass confirmed a diagnosis of adenomatous tubulopapillary polyp. Some evidence of malignant transformation was observed. Palliative treatment with piroxicam suppositories at a dose of 1.4 mg/kg administered rectally every third day was instituted. On re-evaluation, 47 days after starting medical therapy, the owner reported a significant reduction in haematochezia and tenesmus; however, frequency of defecation had remained unaltered. Routine haematology revealed a reduction in the mature neutrophil count (33.67 x 10(9) neutrophils/litre). This report describes a case of a rectal tumour associated with a neutrophilic leucocytosis, which responded to palliative therapy with piroxicam suppositories.     

Orbital multilobular tumour of bone in a dog

A multilobular tumour of bone with left orbital involvement was diagnosed at post mortem examination in an eight-year-old German shepherd cross dog. The tumour resulted in progressive exophthalmos with lateral deviation of the left eye. Radiographs revealed that the mass was mineralised and originated from the left frontal bone with invasion of the left frontal sinus and destruction of the cribriform plate. This is the third reported case of this type of tumour involving the orbit of the dog and thus multilobular tumour of bone should be considered as a differentia] diagnosis of exophthalmos.     

Malignant glomus tumour in a German shepherd dog

A solitary mass, 2.5 cm × 2.5 cm × 2.0 cm in size, was found in the subcutis adjacent to the ischial tuberosity of an 8-year-old male German shepherd dog. The excised mass was not encapsulated and the cut surface was solid, grey–white and had multiple red areas suggestive of haemorrhage. Microscopically, the neoplasm was composed of epithelioid cells interspersed with venous vessels of various sizes and irregular bundles of spindle-shaped tumour cells with mucinous stroma. The nuclei showed anisokaryosis and many mitotic figures were noted. Immunohistochemically, the majority of tumour cells were positive for alpha smooth-muscle actin and vimentin, but negative for cytokeratin, desmin, S-100 and factor VIII-related antigen. Ultrastructurally, the tumour cells contained irregular nuclei, few mitochondria, few rough endoplasmic reticulum, cytoplasmic myofilaments of intermediate density, pinocytotic vesicles and distinct basal lamina. Based on these pathological findings, the diagnosis was malignant glomus tumour.     

IgA multiple myeloma in a dog

Multiple myeloma was diagnosed in a lo-year-old female Labrador which showed signs of weight loss, lethargy and skeletal pain. Radiography revealed well circumscribed osteolytic lesions in vertebrae, sternebrae, and the left humerus and radius along with generalised osteoporosis. The number of plasma cells in the bone marrow was increased and the serum gamma globulin concentration was elevated. Treatment with cyclophosphamide, mephalan and prednisone successfully controlled the malignancy but also resulted in suppression of the bone marrow. There was a remission time of 21.5 months.     

Pancreatic pseudocyst causing extrahepatic biliary obstruction in a dog

A 3-year-old Rhodesian Ridgeback was examined because of recurrent pancreatitis of 2 months duration. The dog had signs of abdominal pain and jaundice. Blood biochemical findings were consistent with extrahepatic bile duct obstruction, but on abdominal ultrasonography no cause of obstruction was identified. At surgery a pancreatic pseudocyst was found in the body of the pancreas. Cystoduodenostomy, cystic omentalisation and biliary diversion resulted in excellent long-term recovery.     

Thrombopathies causing bleeding in a boxer and mixed-breed dog

Hereditary platelet function disorders are clinically characterized by recurrent surface bleeding and prolonged bleeding time, despite normal platelet count and coagulation tests. The authors describe persistent thrombopathies in two young dogs with increased bleeding tendencies but with normal plasma coagulation times and von Willebrand factor (vWf) concentrations. Buccal mucosal bleeding times were prolonged in both dogs. In aggregation studies, platelets underwent only a shape change or minimal aggregation in response to adenosine diphosphate and collagen. Whole-platelet adenine nucleotide concentrations were normal. Electron microscopic evaluation of fibrinogen and vWf binding to the platelets of case no. 1 demonstrated the presence of glycoprotein IIb/IIIa and Ib receptors. Thus, the intrinsic platelet function defects may be different in these two dogs and may likely represent secretion/signal transduction disorders.     

IgA multiple myeloma in a dog

Multiple myeloma was diagnosed in a 10-year-old female Labrador which showed signs of weight loss, lethargy and skeletal pain. Radiography revealed well circumscribed osteolytic lesions in vertebrae, sternebrae, and the left humerus and radius along with generalised osteoporosis. The number of plasma cells in the bone marrow was increased and the serum gamma globulin concentration was elevated. Treatment with cyclophosphamide, mephalan and prednisone successfully controlled the malignancy but also resulted in suppression of the bone marrow. There was a remission time of 21.5 months.     

Primary prostatic haemangiosarcoma causing severe haematuria in a dog

A 10-year-old, entire, male, mixed-breed dog was presented for severe haematuria and stranguria. Ultrasound revealed a large intraluminal urinary bladder blood clot and a prostatic space-occupying lesion. Invasion of the lesion into the prostatic urethra was detected ultrasonographically during compression of the urinary bladder. Post-mortem examination revealed primary prostatic haemangiosarcoma infiltrating the urethra. Haemangiosarcoma should be considered as a rare cause of prostatic mass lesions, haematuria or lower urinary tract signs in dogs.