Surgical removal of a choroid plexus oncocytoma in an adult cat

An 11‐year‐old male castrated domestic shorthair cat presented with left central vestibular dysfunction. Magnetic resonance imaging of the brain revealed a large, extra‐parenchymal, strongly contrast‐enhancing mass at the level of the left cerebellopontine angle and compressing the cerebellum and brainstem. The mass was surgically excised via left rostral and sub‐tentorial craniectomies and histopathology revealed an epithelial neoplasm composed of anastomosing cords of neoplastic cells that contained large amounts of finely granular hypereosinophilic cytoplasm and round nuclei. The cytoplasmic granules were variably positive with periodic acid‐Schiff and modified Gomori trichrome. Immunohistochemical staining with anti‐cytokeratin AE1/AE3 was diffusely positive. Electron microscopy revealed neoplastic cells that were full of electron‐dense organelles consistent with mitochondria. This is the first case of a choroid plexus oncocytoma in the central nervous system of any domestic animal species and highlights the role of successful surgical intervention in extra‐parenchymal neoplasia in the central nervous system.     

Surgical removal of an intramedullary chopstick fragment penetrating the spinal cord in a cat

A 3-year-old male domestic shorthair cat presented with sudden ataxia. Neurologic examination showed complete loss of proprioception in the thoracic and pelvic limbs. Computed tomography and magnetic resonance imaging revealed a non-metallic foreign body penetrating the spinal cord. The foreign body was removed by the ventral approach to the atlanto-occipital junction. Mild improvement of proprioception was observed the day after surgery. In a follow-up two months after surgery, the owner reported a complete recovery of the patient, showing a normal gait. To the author’s knowledge, this is the first case report describing successful removal of an intramedullary foreign body penetrating cervical spinal cord by ventral approach in a cat.     

Persistent atrial standstill in a cat

A domestic shorthaired cat was presented with a 1-month history of cardiomegaly and recurrent chylothorax. The heart rate was 130 beats/min and no P waves were present on a surface electrocardiogram. Thoracic radiographs and an echocardiogram demonstrated severe biatrial dilatation, pleural effusion and restrictive pleural disease. Permanent atrial standstill was suspected. Pleurocentesis was performed and therapy was started with enalapril, frusemide and aspirin. Intracardiac electrograms revealed no atrial activity, and atrial pacing failed to elicit atrial or ventricular depolarisations. The patient was euthanased. Necropsy showed severe atrial wall thinning with marked cardiocyte loss. Persistent atrial standstill is a rare disease in the cat. Clinical signs may have been due to loss of atrial function, ventricular diastolic dysfunction, bradycardia, neurohormonal activation and reduced atrial natriuretic peptide plasma concentrations.     

Dermal mass aspirate from a Persian cat

A 1-year-old spayed female Persian cat with alopecia and weight loss had numerous variably ulcerated dermal nodules. Cytologic examination of an aspirate of one of the nodules revealed pyogranulomatous inflammation along with septate hyphae and basophilic round bodies, 0.5–1.0 μm in diameter, surrounded by a thin clear halo (arthrospores). The cytologic diagnosis was dermatophytic pseudomycetoma. Histologically, there were dermal granulomas containing poorly staining, septate hyphae with bulbous spores embedded within abundant amorphous eosinophilic material (Splendore-Hoeppli reaction), and the histologic diagnosis was pseudomycetoma-associated chronic multifocal severe granulomatous dermatitis with lymphocytic perifolliculitis and furunculosis. Microsporum canis was cultured from the lesion. Pseudomycetomas are distinguished from fungal mycetomas, or eumycotic mycetomas, by the findings of multiple lesions, lack of a history of skin trauma, an association with dermatophytes, most commonly Microsporum canis , and, histologically, lack of true cement material and a more abundant Splendore-Hoeppli reaction in pseudomycetomas. Additionally, pseudomycetomas differ from dermatophytosis, in which lesions are restricted to epidermal structures. Persian cats have a high incidence of pseudomycetoma formation, suggesting a heritable predisposition. The prognosis is fair with systemic antifungal therapy. When examining cytologic specimens from Persian cats with single or multiple dermal nodules, especially if pyogranulomatous inflammation is present, a diagnosis of pseudomycetoma should be suspected and is warranted if arthrospores and refractile septate hyphae are present.     

Image-guided interventional procedures in the dog and cat

Medical imaging is essential for the diagnostic workup of many soft tissue and bone lesions in dogs and cats, but imaging modalities do not always allow the clinician to differentiate inflammatory or infectious conditions from neoplastic disorders. This review describes interventional procedures in dogs and cats for collection of samples for cytological or histopathological examinations under imaging guidance. It describes the indications and procedures for imaging-guided sampling, including ultrasound (US), computed tomography (CT), magnetic resonance imaging and fluoroscopy. US and CT are currently the modalities of choice in interventional imaging.     

Deep and superficial skin scrapings from a feline immunodeficiency virus-positive cat

An 8-year-old, neutered male, domestic shorthair cat housed at the North Carolina State University, College of Veterinary Medicine, Laboratory Animal Research facility as part of a research colony was examined because of mulifocal skin lesions. The lesions consisted of patchy alopecia with mild crusting of the periauricular region, neck, and dorsum; periauricular excoriations; marked dorsal seborrhea and scaling; and generalized erythematous papules. A moderate amount of ceruminous exudate was present in both ear canals. Results of testing for feline immunodeficiency virus (FIV) were positive. An ear swab specimen and superficial and deep skin scrapings were obtained, mounted with oil on glass slides, and coverslipped for microscopic examination. Two populations of mites were observed: a large population of slender, long (approximately 200 microm), adult mites with long, tapering abdomens that comprised two-thirds of the total body length; and a smaller population of more translucent and shorter mites (approximately 100 microm) with wide, blunt abdomens that had prominent transverse ridges. The interpretation was demodicosis, with Demodex cati and D gatoi co-infection. Histologic sections of biopsies from skin lesions on the neck, dorsum, and periauricular area contained a mild perivascular and perifollicular inflammatory infiltrate composed predominantly of histiocytes, lymphocytes, and plasma cells. Diffusely within the follicular lumina and occasionally within the superficial keratin, a myriad of Demodex organisms were observed. Intrafollicular mites were compatible in appearance with D cati whereas those in the corneal layer were suggestive of D gatoi. Demodicosis is an uncommon disease of cats, and rare cases of dual infection have been documented, occasionally in FIV-infected cats. The dual infection emphasizes the importance of doing both superficial and deep skin scrapings and of recognizing the unique microscopic features of different Demodex mites.     

Blood smear from a pregnant cat that died shortly after partial abortion

A 1-year-old, 5- to 6-week pregnant cat was presented with a history of aborting 3 kittens the previous night. During the examination, the cat began to seizure and died. At necropsy, formalin-fixed tissues and blood smears prepared from an EDTA blood sample collected via cardiac puncture were submitted to a diagnostic laboratory. Examination of the blood smears revealed numerous large (15-75 microm) clumped macrophages containing dark blue intracytoplasmic organisms consistent with Cytauxzoon merozoites. Scattered erythrophagocytic macrophages were also observed. Within several erythrocytes, 1-2 small, round, ring-like piroplasms consistent with Cytauxzoon were observed. Histologic examination revealed numerous large, schizont-laden macrophages filling the blood vessels of multiple organs. The cytologic and histologic findings were diagnostic for Cytaxuzoon felis infection. This case was of particular interest because of the unusually large number of organism-laden macrophages in the cardiac blood sample, an uncommon finding in peripheral blood. Although the cat was presented for complications of abortion, it remains uncertain whether C felis organisms crossed the placenta and infected the fetuses or lead to the abortions.     

Toxoplasma gondii-like organisms in skin aspirates from a cat with disseminated protozoal infection

An 8-year-old, male domestic shorthair cat was referred to the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania with a 3-day history of lethargy, inappetance, hyperemic skin nodules, coughing, and vomiting. Laboratory results included nonregenerative anemia, lymphopenia, thrombocytopenia, hypoalbuminemia, hyponatremia, and increased alanine aminotransferase and aspartate aminotransferase activities. Cytology of the skin nodules revealed many spindle- to crescent-shaped protozoal organisms, with morphology consistent with Toxoplasma gondii or Neospora caninum. Gross necropsy, histopathologic, immunohistochemical, and transmission electron microscopic findings confirmed a systemic protozoal infection; however, the organism exhibited characteristics of both N caninum and T gondii. Diagnosis of a T gondii-like infection was based on internal structures of the organism and positive reaction to rabbit polyclonal antibodies to T gondii. Reports of toxoplasmic dermatitis are rare in the cat and dog, and this is the first reported diagnosis of T gondii-like protozoa in skin aspirates.     

Hemangiosarcoma of the third eyelid in a cat

A case of hemangiosarcoma of the third eyelid in a 15-year-old Domestic Short-haired cat is reported. A small red mass protruding from the anterior surface of the third eyelid in the left eye was present. Only mild bilateral conjunctivitis and nuclear sclerosis were revealed on initial ophthalmic examination. After anti-inflammatory treatment, surgery and cryotherapy were performed. On histopathologic examination the mass was located just beneath the conjunctival epithelium, suggesting that the conjunctiva was the tissue of origin. The tumor showed high cellularity and was composed of pleomorphic spindle and polygonal cells arranged in interlacing bundles and solid sheets. The presence of slit-like spaces between tumor cells containing erythrocytes demonstrated the vascular differentiation. Mitotic activity was moderate, but atypical mitoses were detected. The surgical area healed uneventfully and after 7 months there was no recurrence. To the authors' knowledge, this is the first report of conjunctival hemangiosarcoma of the third eyelid in a cat.     

Clinical,virological, imaging and pathological findings in a SARS CoV-2 antibody positive cat

This paper reports a presumptive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a cat. A cat with respiratory disease living with three individuals with coronavirus disease 2019 showed bilateral ground-glass opacities in the lung on X-ray and computed tomography. The clinical swabs were negative for SARS-CoV-2 RNA, but the serum was positive for SARS-CoV-2 antibodies. Interstitial pneumonia and prominent type 2 pneumocyte hyperplasia were noted on histopathology. Respiratory tissues were negative for SARS-CoV-2 RNA or antigen, but the cat was positive for feline parvovirus DNA. In conclusion, the respiratory disease and associated pathology in this cat could have been due to exposure to SARS-CoV-2.     

Surgical correction of temporomandibular joint ankylosis in two cats

Two cats with temporomandibular joint ankylosis were examined. Difficulty in opening the mouth and malocclusion were associated with trauma and fracture around the zygomatic arch and the condyle of the mandible after an automobile accident. Unilateral condylectomy or aggressive caudal mandibulectomy was performed to improve quality of life. Excision arthroplasty of the temporomandibular joint improved mandibular function and appearance. Some malocclusion remained but had no clinical significance.     

Surgical removal of a fish hook from the oesophagus of a turtle

An adult male Macquarie turtle was presented for examination after swallowing a fish hook. Radiographs taken to determine the position of this foreign body within the gastrointestinal tract revealed the fish hook lodged in the turtle's oesophagus. Surgical removal of the fish hook involved an approach through the soft tissues of the lateral neck. The turtle recovered well and was returned to the wild.     

Surgical removal of a fish hook from the oesophagus of a turtle

An adult male Macquarie turtle was presented for examination after swallowing a fish hook. Radiographs taken to determine the position of this foreign body within the gastrointestinal tract revealed the fish hook lodged in the turtle's oesophagus. Surgical removal of the fish hook involved an approach through the soft tissues of the lateral neck. The turtle recovered well and was returned to the wild.     

C-arm fluoroscopy for the removal of an intraorbital foreign body in a cat

This report describes the clinical manifestations, diagnosis and minimally surgical intervention of a cat with an intraorbital foreign body. A spayed female cat of unknown age was presented with a recurrent cutaneous sinus tract of the left suborbital region. The cat had not vocalized at all since the adoption. A sharp-edged radiopaque foreign body was visualized on dental radiography. Computed tomography outlined the length of the foreign body from the intraorbital soft tissue to the pharynx. The foreign body was removed under the guide of C-arm fluoroscope with minimal skin incision. The surgical site healed completely on the 11th postoperative day, and the cat vocalized normally after healing.