Actinomyces infection in a dog with pulmonary carcinoma

Thoracic actinomycosis was diagnosed by bacterial isolation in a dog with a history of chronic productive cough, weight loss, pyrexia and a pulmonary mass lesion on radiography. Therapy with amoxycillin and clindamycin did not significantly improve the patient's condition and euthanasia was performed during exploratory thoracotomy. Histological examination of the affected lung lobes revealed the presence of peribronchiolar adenocarcinoma. Actinomycosis has been reported to co-exist with pulmonary neoplasia in humans and may mask the presence of malignancy.     

Corneal squamous cell carcinoma in a dog

A squamous cell carcinoma in situ (corneal intraepithelial neoplasia) was diagnosed in the right eye of an 11-year-old female Golden Retriever. Papillomavirus antigen was not detected in the excised tissues, and the tumor was suspected to be a sequel to previous injury. The tumor was removed by lamellar keratectomy, and the surgical bed was subjected to double freeze-thaw cryotherapy. Tumor regrowth was not apparent approximately one year after treatment.     

A case of anaplastic meningioma in a dog

A tumor sized in 2.0x2.0x2.5 cm developed in the cerebellum of a female Beagle was pathologically investigated. Histopathologically, the tumor grew by compression and partially by infiltration into the adjacent cerebellar parenchyma. There were a large number of necrotic lesions and proliferation of collagen fibers. The tumor cells had oval nucleus showing cellular atypia and a high mitotic index. The tumor cells were reacted with vimentin antibody on immunostain. Electron microscopic examination revealed the tumor cells interdigitated with cytoplasmic processus where the desmosomes developed on cell junction. This tumor was diagnosed as anaplastic meningioma, which is rarely observed in dogs.     

Concurrent sialocoele and necrotising sialadenitis in a dog

A seven-year-old male, entire rottweiler was presented to Murdoch University Veterinary Hospital with a 24 hour history of blindness, chemosis, exophthalmus, pain on opening the mouth and hypersialism. Bilateral mandibular and zygomatic salivary gland enlargement with concurrent bilateral zygomatic salivary gland sialocoeles were identified. The cause of the mandibular salivary gland enlargement was confirmed as necrotising sialadenitis, while the cause of the zygomatic gland enlargement was presumed to be because of a similar disease process. No underlying aetiology was identified. Treatment consisted of supportive management, corticosteroids and paracentesis of the sialocoeles and resulted in resolution of the salivary gland enlargement and the associated clinical signs. This is an unusual presentation of salivary gland disease in the dog with multiple gland involvement and a spectrum of disease processes occurring at the same time.     

Hypertrophic osteopathy associated with pulmonary adenosquamous carcinoma in a dog

A six-year-old intact female Maltese dog weighing 3.8 kg presented with a history of mild lameness and swelling on both forelimbs. Radiographic and computed tomographic views revealed an extensive periosteal reaction in all four limbs and a large round mass on the right middle lung lobe. A total lobectomy was performed and pulmonary adenosquamous carcinoma was histologically confirmed. A diagnosis of hypertrophic osteopathy (HO) secondary to a lung tumor was made. Periosteal proliferation decreased significantly after surgery; however, there was evidence of dyspnea, mass recurrence, and periosteal reaction three months post-operatively. This is the first case report of pulmonary adenosquamous carcinoma with HO in a dog in which we describe clinical, imaging, surgical, and histological findings.     

Intracranial anaplastic astrocytoma in a 19-week-old boxer dog

A 19-week-old, entire female boxer dog was presented for evaluation of chronic, progressive multi-focal neurological signs. Magnetic resonance imaging suggested a large intra-axial mass in the brainstem. Euthanasia was performed and an anaplastic astrocytoma was found at post-mortem examination. This case reports an unusual naturally occurring brain tumour in a young dog.     

Positron emission tomography/computed tomography imaging features of renal cell carcinoma and pulmonary metastases in a dog

A 9-year-old spayed female cocker spaniel dog was referred for hematuria. A large abdominal mass and multiple pulmonary nodules were identified radiographically. A whole-body 2-deoxy-2-[¹⁸F]fluoro-d-glucose positron emission tomography/computed tomography (PET/CT) scan revealed intensely increased uptake in a renal mass and the pulmonary nodules. Renal cell carcinoma was diagnosed on histological examination.     

Retrobulbar anaplastic astrocytoma in a dog: clinicopathological and ultrasonographic features

An 11-year-old entire female German shepherd dog was presented with a progressive non-painful exophthalmos of the right eye. Ultrasonographic examination revealed a solid and well-defined orbital mass compressing the globe. Thoracic radiography revealed multiple pulmonary metastases of different sizes. The histopathological and immunohistochemical features of both the retrobulbar tumour and pulmonary metastases were consistent with an anaplastic astrocytoma. This represents an unusual case of an extracranial astrocytoma with multiple pulmonary metastases. The clinical features and the ultrasonographic, histopathological and immunohistochemical findings are described.     

Multiple joint metastasis of a transitional cell carcinoma in a dog

An 8‐year‐old castrated male hound mix was referred to the Purdue University Veterinary Teaching Hospital for severe lameness, pollakiuria, and dyschezia. On presentation, the dog was nonweight bearing on the right rear limb and the right carpus was diffusely swollen. Synovial fluid analysis from the right carpus revealed a population of epithelial cells displaying marked anisocytosis, anisokaryosis, multinucleation, and prominent, variably sized nucleoli. A metastatic carcinoma with presumed prostatic or urothelial origin was diagnosed based on cytomorphology. Subsequent cytologic evaluation of peripheral lymph nodes revealed the presence of a similar neoplastic population. The dog was euthanized and synovial fluid from both stifle joints, as well as impression smears of the prostate gland, were collected. Carcinoma cells were identified in each stifle joint and in the prostate gland. Immunocytochemistry was performed on synovial fluid smears from 2 of the joints (right stifle and right carpus) and on impression smears of the prostate gland. The neoplastic population in the joints and prostate gland showed strong immunoreactivity to uroplakin III, a urothelial marker, indicating metastasis of a transitional cell carcinoma to multiple joints. In addition, evidence for epithelial to mesenchymal transition was identified using cytokeratin, an epithelial marker, and vimentin, a mesenchymal marker. A necropsy was performed and histopathology confirmed the presence of metastatic transitional cell carcinoma in various tissues. This case illustrates the importance of considering metastatic disease when a patient is presented with severe lameness and joint pain, and the clinical utility of synovial fluid cytology for diagnosis of metastasis in these cases.     

Corneal squamous cell carcinoma in a dog: a case report

Purpose:  To report a case of primary corneal squamous cell carcinoma (SCC) in an English Bulldog. In addition, immunohistochemistry of the corneal tissue mass was performed using a panel of antibodies. A prominent feature of the present case was the clinical history of chronic keratitis due to eyelid abnormalities.
Results:  No papillomavirus antigen was detected in section of normal or neoplastic corneal tissue. The corneal epithelial cells were positive for pancytokeratins AE1/AE3 and MNF116, and E-cadherin. The neoplastic cells in close proximity to the normal epithelial lining were positive for both pancytokeratins and E-cadherin with gradual loss of staining toward the center of the neoplastic mass. Rare neoplastic cells demonstrated positive staining for caspase 3 and a large number was strongly positive for GADD45 and p53.
Conclusion and discussion:  The observed loss of the various cytokeratins, the strong p53 expression, and low numbers of caspase 3 positive cells were suggestive that a p53 mutation may have caused this primary corneal SCC. Over-expression of the tumor-suppressor gene p53 is likely to be a consequence of ultraviolet radiation exposure. Two factors, however, may have played a role in the formation of this primary corneal SCC: chronic irritation of the corneal surface (microtrauma) and exposure to UV radiation.