Multilobular tumor of the mandible in a Pekingese dog

Multilobular tumor of bone detected in a 2.5-year-old male Pekingese dog is reported. Grossly, the neoplasm consisted of multiple, variably sized, gritty, grayish-white to yellow nodules separated by thick collagenous septa. Histologically, these nodules contained multiple lobules of irregularly shaped and sized islands of well-differentiated osteoid and cartilage, separated by anastomosing fibrovascular septa. Chondrocytes and osteocytes were observed in the lacunae and in more osseous islands in the lobule, respectively. These lobules were surrounded by mesenchymal spindle cells. Mitotic figures were not evident. The neoplastic pattern was consistent with that of a multilobular bone tumor. Diagnosis was based on gross and light microscopic findings. The cause of this neoplasm was not determined.     

Acute tumour lysis syndrome in a dog with B-Cell multicentric lymphoma

A 5-year-old, spayed female German Shepherd dog was admitted to hospital with marked generalised lymphadenomegaly and splenomegaly. A stage Va B-cell multicentric lymphoma was diagnosed on clinical, cytological (lymph node, bone marrow), histological-immunohistochemical (lymph node excision) and imaging grounds. Since no satisfactory remission was achieved using a multi-drug chemotherapy protocol that included cyclophosphamide, vincristine, cytosine arabinoside, prednisolone, and subsequently supplemented by L-asparaginase, it was replaced by another protocol combining vincristine, L-asparaginase, prednisolone, cyclophosphamide and doxorubicin. Soon after the third weekly session of the second protocol, the clinical status of the animal deteriorated suddenly and severely, with a bleeding tendency, jaundice, hyperuricaemia, hyperphosphataemia, azotaemia, hyperbilirubinaemia and, presumptive disseminated intravascular coagulation. There was also complete regression of lymphadenomegaly. This report emphasises the clinicopathological features and the diagnostic peculiarities of the acute tumour lysis syndrome, which occurs uncommonly in dogs.     

Morphometric analysis of the cranial cavity and caudal cranial fossa in the dog: a computerized tomographic study.

This investigation was initiated to develop a reliable and simple computerized tomography (CT) method for evaluating the morphometry of the cranial cavity (CC) and caudal cranial fossa in the dog. We obtained linear, area, and volume measurements of the entire CC and the caudal fossa compartment in 24 dogs, using transverse and reformatted sagittal and dorsal CT images. The ratios between the CC and the caudal fossa volumes were calculated, as were the ratios between the CC and caudal fossa midsagittal (MS) areas. There were statistically significant correlations between absolute volume data and certain linear measurements, a positive correlation between volume ratio and weight, and significant differences in absolute volume values and volume ratio between males and females. The volume ratio, MS area, and certain linear measurements included in this study can be considered as accurate parameters to evaluate the relative size of the CC to caudal fossa in the dog. Such quantitative measures may be useful in systematically characterizing Chiari-type malformations and other developmental anomalies in the dog.     

Muscular and collagenous cerebellar choristoma in a dog

This report aims to describe the first case of muscular and collagenous choristoma in a dog. A 10-yr-old female mixed-breed dog presented with lateral recumbence, vocalization, positional vertical nystagmus, divergent strabismus, anisocoria, and status epilepticus. The clinical condition evolved to stupor and ultimately, death. Necropsy revealed a white mass causing an irregular increase in the volume of the cerebellar vermis. In histological analysis, a well circumscribed, unencapsulated mass was observed in the cerebellum, consisting of fibers of striated skeletal muscle and collagen fibers, mostly mineralized. Based on the histopathological and histochemical findings, a diagnosis of muscular and collagenous cerebellar choristoma was made.     

Multilobular tumour of bone at an unusual location in the axilla of a dog

Multilobular tumour of bone is a rare neoplasm of cartilage, bone and connective tissue that is seen almost exclusively in association with the skull of veterinary patients. A four-year-old, spayed Jack Russell terrier was presented to the University of Georgia Veterinary Teaching Hospital because of a progressive swelling in the right axilla. Radiographs of the region showed the mass to be caudal to the scapula, unattached to bone and to have numerous punctate calcific opacities throughout its substance. Excisional biopsy of the mass was carried out under general anaesthesia and histopathological examination showed it to be multilobular tumour of bone. This case report documents the occurrence of multilobular tumour of bone at a site other than the head. This tumour should be considered in the differential diagnosis of soft tissue masses with calcific opacities.     

Primary chondrosarcoma in the skull of a dog

Chondrosarcoma of the skull is a rare primary malignant tumor that is slow-growing, but locally aggressive. A 5-year-old, golden retriever was presented to our hospital with a swelling in the left side of her head, and the swelling had slowly enlarged over the previous month. There were no significant changes on the neurological examination. A computed tomography scan revealed a large mass involving bone destruction and prominent matrix mineralization. T1-weighted magnetic resonance imaging showed a slightly low-signal intensity area and a T2-weighted image revealed marked, high-signal intensity. There was compression of the adjacent brain parenchyma. Histopathological examination confirmed the lesion to be a chondrosarcoma.     

Multilobular tumour of bone with no abnormalities on plain radiography in a dog

A seven-year-old neutered female golden retriever was presented for an acute onset of cervical pain and ataxia. Intervertebral disc disease or neoplasia was suspected. There was no evidence of a soft tissue or bony mass on physical examination or survey radiographs. Cerebrospinal fluid analysis did not show any evidence of a neoplastic process. Myelographic evaluation identified an extradural mass lesion extending from inside the calvarium to the mid-body of the first cervical vertebra. No additional diagnostic tests were performed as the owners elected for euthanasia because of the high possibility of a neoplastic process with an accompanying poor prognosis. Multilobular tumour of bone was diagnosed on postmortem examination.     

Fibro‐osseous tumour of the second metacarpal bone in a Thoroughbred filly

A 7‐month‐old Thoroughbred filly was evaluated because of an enlarging mass present on the proximomedial aspect of the left metacarpus. The mass was first noticed at age 2 months and had continued to increase in size. The mass was firm, nonpainful to palpation, covered with normal haired skin and had never been associated with lameness. Radiographs obtained at ages 2 and 7 months revealed an enlarging and partially mineralised mass associated with the second metacarpal bone. Based on the clinical and radiographic progression, as well as the location of the mass, a poor prognosis for future athletic soundness was given and the filly was subjected to euthanasia. The mass had histological features of both an ossifying fibroma and osteoma.     

Multilobular osteochondrosarcoma of the os penis in a dog

Multilobular osteochondrosarcoma (MLO) of the os penis was diagnosed in a dysuric dog. Recurrence was confirmed or suspected twice over a 22-month period. This is the first reported case of MLO occurring in the os penis, and the 5th reported case of neoplasia of the os penis in the dog.     

Multilobular osteochondrosarcoma of the hard palate in a dog

A 14-year-old castrated male Rhodesian Ridgeback was presented with a history of sneezing and epistaxis. Diagnostic procedures included physical examination, regional and thoracic radiography, computed tomography and histological examination of an incisional biopsy. A multilobular osteochondrosarcoma of the hard palate with pulmonary metastases was diagnosed. Surgical resection of the primary tumour was achieved with clean margins and the defect was repaired using bilateral mucosal transposition flaps from the lips. Wound dehiscence and oesophageal stricture were postoperative complications, but these resolved with treatment. A long-term survival time of 14 months resulted, with good quality of life and function during this time.     

Multilobular tumor of bone in the mandible of a dog

An 8-year-old Siberian husky dog was presented for a mass involving the rostral mandible. Intraoral radiographs demonstrated diffusely irregular bone and displacement of all mandibular incisor teeth. The mass was diagnosed as a grade I multilobular tumor of bone based on incisional biopsy. A bilateral rostral mandibulectomy was performed with tumor negative margins. Oral examination at 14-months following surgery indicated normal healing with minimal side effects and no evidence of tumor recurrence.     

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.     

Fibro‐osseous tumour of the fourth metacarpal bone in a horse: Clinical,radiographic and long‐term post operative findings

This case study describes a rare case of a fibro‐osseous tumour in the distal part of the fourth metacarpal bone of a 13‐year‐old horse. The tumour was surgically removed and wound healing occurred without complications. A specific diagnosis was reached by considering the clinical and histological features of the mass. However, the process was complicated by the different classification systems for this type of tumour. When classified according to the veterinary literature, ossifying fibroma is the appropriate diagnosis, whereas in human medicine this term has been replaced.     

Presumptive caudal cerebellar artery infarct in a dog: clinical and MRI findings

Clinical signs and magnetic resonance imaging findings of a caudal cerebellar artery infarct are reported for the first time in a dog. Clinical signs were characterised by a peracute, non-progressive, right-sided central vestibular syndrome with paradoxical right-sided head tilt. Magnetic resonance images were consistent with a territorial, non-haemorrhagic, ischaemic lesion affecting the caudo-ventral part of the right cerebellar hemisphere, mainly involving the right paramedian lobe, the ansiform lobe and the caudal cerebellar peduncle. Bloodwork results were suggestive of an underlying hypercoagulable state, although the concomitant presence of a histologically confirmed mammary gland adenocarcinoma could have also been related to the cerebellar vascular obstruction through metastatic emboli formation. Posterior-inferior cerebellar artery infarction is the human equivalent of caudal cerebellar artery infarct in dogs.     

Multimodality imaging of an azygous continuation of the caudal vena cava in a dog with pulmonary thromboembolic disease

A 5‐year‐old spayed female English Bulldog was evaluated for acute anorexia, lethargy, respiratory distress, and syncope. Contrast‐enhanced computed tomography revealed the vascular malformation of azygous continuation of the caudal vena cava with extensive thrombus formation and pulmonary arterial thromboembolic disease. The patient was hospitalized for supportive treatment and was prescribed long‐term clopidogrel therapy. The patient survived to discharge and at last follow‐up remained clinically stable. While this vascular malformation has been reported in canines, to the authors’ knowledge, this is the first reported case of pulmonary thromboembolic disease in a canine concurrent with this condition.     

Histopathological findings in the early diagnosis of granulosa cell tumour in bitches

Granulosa cell tumour (GCT) is a majorly observed ovarian tumour in female dogs. It is essential to diagnose GCT in its initial phase before any symptoms occur, as histological and physiological differences may be observed based on the evolution of this neoplasia. This study aimed to analyse the anatomic histopathology of GCT in its initial stage, with findings of ovaries not yet with the suspicion of neoplasms in the Canis familiaris. A sample including 55 ovaries presented GCT in 40 female dogs. The histopathological analysis was performed considering the intensity of pleomorphism, vascularization and inflammatory infiltrate. Furthermore, we evaluated the mitoses count in 10 fields using 40× magnification. Out of the 40 animals evaluated, 62.5% (25/40) presented the tumour in only one ovary. The Call‐Exner corpuscle was present in 65% (26/40) of the cases. The follicular histological pattern was present in 52.5% (21/40) of the animals. The presence of the Call‐Exner bodies and the degree of tumour cell pleomorphism (p = 0.033) were associated. Moreover, the degree of vascularization and the intensity of the inflammatory infiltrate were also related (p = 0.001). In addition, there was a positive relationship between the increase in pleomorphism and the mean age of the animals (p = 0.044). This study confirmed that the appearance of this tumour may precede any clinical symptomatology. In this study, the most frequent histopathological pattern was the follicular. The characteristics of the granulosa cell tumour diagnosed early were poorly pleomorphic cells, low mitotic index and presence of Call‐Exner body.     

Multilobular tumour of bone of the thoracic wall in a cat

Multilobular tumour of bone is a rare neoplasm of the skull in middle-aged, medium-to-large breed dogs even if a few cases have also been described in cats and one horse. The aim of the present paper is to show both the computed-tomography features and the pathological findings of the above neoplasm affecting the thoracic wall of a cat. To the best of the authors' knowledge, such anomalous tumour localisation has never been reported and imaged in feline medicine.