Andrew Holloway

Use of contrast ultrasonography in the diagnosis of metastatic feline visceral haemangiosarcoma

A 12-year-old cat was presented for investigation of weight loss and inappetence. Radiography and conventional grey-scale ultrasonography showed a large mid-body splenic mass. Contrast enhanced ultrasonography of the liver demonstrated a hypoechoic left lateral lobe nodular mass during the peak and late portal-phases of liver enhancement. Histopathology of the splenic mass and hepatic nodular mass confirmed haemangiosarcoma. The use of ultrasound microbubble contrast media in the diagnosis of hepatic metastasis in the cat has not been previously reported in the cat.

IMAGING DIAGNOSIS—THROMBOSED ORBITAL VARIX IN A DOG

A 9-week-old female Rhodesian Ridgeback presented with exophthalmos following minor blunt trauma to the left orbital area. Ocular ultrasound showed an extraconal retrobulbar mass ventromedial to the left globe. Magnetic resonance (MR) imaging demonstrated a thrombosed orbital vascular malformation without intracranial extension. Doppler ultrasound features of nonpulsatile slow flow were consistent with an orbital varix. Contrast-enhanced dynamic time-resolved and high-resolution MR angiography demonstrated the varix arose from the anastomotic branch of the dorsal and ventral external ophthalmic veins. Conservative management led to a positive outcome defined as a visual eye and nearly normal cosmetic appearance at 8-month follow-up.

Intradiploic hematoma of the frontal bone with secondary exophthalmos in a mare.

A 13-year-old cob mare was presented with exophthalmos and periocular swelling of the left eye. The diagnostic work-up included ocular ultrasound, sonographic examination through the thinned frontal bone, radiography, standing computed tomography of the skull and exploratory osteoplastic surgery. Histopathology was consistent with an organized hematoma. An intradiploic hematoma of the frontal bone was diagnosed 5 years after head trauma, with progressive expansion and deformation of the skull resulting in exophthalmos. Exophthalmos with facial bone deformation was the only clinical finding of intradiploic hematoma. Standing computed tomography (CT) aided the diagnosis to differentiate intradiploic hematoma from other, more common causes of facial bone distortion associated with paranasal sinus diseases. Intradiploic hematoma of possible traumatic origin is a differential diagnosis for sinonasal disease and exophthalmos in the horse.

IMAGING DIAGNOSIS–UNILATERAL TRIGEMINAL NEURITIS MIMICKING PERIPHERAL NERVE SHEATH TUMOR IN A HORSE

A 16-year old Warmblood gelding presented with a nonhealing corneal ulcer and absent corneal sensation in the left eye. A lesion affecting the maxillary and ophthalmic branches of the left trigeminal nerve was suspected. Magnetic resonance (MR) imaging identified marked thickening of the ophthalmic and maxillary branches of the left trigeminal nerve. The nerve was iso- to hypointense on T1-weighted and T2-weighted images with heterogeneous enhancement. A peripheral nerve sheath tumor was suspected, however granulomatous neuritis was histopathologically confirmed. These inflammatory changes can result in severe nerve enlargement and should be considered with MR findings suggestive of peripheral nerve sheath tumor.

Cerebral coenurosis in a cat

A two-year-old female Birman cat presented with progressive abnormal behaviour, lethargy and circling towards the left. MRI demonstrated a large, solitary, intraxial expansile thin-walled cyst, without surrounding oedema or enhancement, in the left frontoparietal region. Severe subfalcian, caudal transtentorial and foramen magnum herniation were present. The owners declined treatment and the cat was euthanased. Postmortem examination demonstrated a coenural cyst with multiple larval protoscolices molecularly confirmed as Taenia serialis. Recognition of characteristic MRI findings of feline cerebral coenurosis is necessary if antemortal diagnosis and management of this, to date, invariably fatal neurological condition is possible.

Contralateral optic neuropathy and retinopathy associated with visual and afferent pupillomotor dysfunction following enucleation in six cats

PURPOSE To investigate contralateral optic neuropathy and retinopathy following enucleation in 6 cats. METHODS Retrospective study. The medical records of cats with contralateral visual and afferent pupillomotor dysfunction following enucleation presented to the Animal Health Trust (AHT), Newmarket, UK, between January 1994 and January 2010 were reviewed. Information recorded included history, signalment, ophthalmic findings, electroretinography (ERG) (2/6) and MRI (3/6) findings and long-term outcome. Pearsons chi-square tests were used to compare breed proportions (P < 0.05). RESULTS Six cats aged 1.5 to 11 (median 5.5) years presented with mydriasis and/or visual deficits noted immediately following enucleation. Enucleation involved optic nerve (ON) ligation in all of the four cases for which this information was available. Ophthalmic findings included mydriasis with absent pupillary light reflex (PLR) (4/6), incomplete PLRs (2/6), absence of dazzle reflex (4/6) and absence of menace response (4/6). Funduscopy initially revealed multifocal peripapillary retinal lesions, with subsequent progressive optic nerve head (ONH) and retinal atrophy. ERG recordings revealed normal outer retinal function at 6 and 22 weeks (2/2). On MRI, the optic chiasm (OC) ipsilateral to the enucleation could not be identified and the contralateral OC was atrophied (3/3). CONCLUSIONS The acute afferent ON deficits following enucleation, progressive ONH atrophy, normal outer retinal function and MRI demonstrating OC pathology are consistent with chiasmal injury due to traction on the ON during enucleation. Rostral traction on the globe to facilitate ON ligation is contraindicated in cats.

Practical ultrasonography – the VN perspective

ABSTRACT: In diagnostic ultrasonography, high-frequency sound waves generated by a transducer are reflected back from within the patient to produce a two-dimensional image of internal organs and structures. The image is displayed as a grey-scale, cross-sectional image. Blood flow can be demonstrated either as a grey-scale velocity profile (spectral Doppler) or as a colour map (colour Doppler). Ultrasound transducer construction is adapted to allow evaluation of superficial structures and images subcostally or intercostally, even in small patients. Recognition of the ultrasonographic appearance of normal structures is an important part of the diagnostic process, as disease may present as either focal or diffuse change.

Unilateral eyelid lesion and ophthalmologic findings in an aardvark (Orycteropus afer): case report and literature review.

OBJECTIVE To summarize the medical knowledge surrounding aardvarks to date, to describe the ophthalmic examination of a specimen with a chronic history of an upper eyelid lesion, of an assumed blind left eye, and to detail the anesthesia procedure performed. PROCEDURE A 23-year-old aardvark was examined under general anesthesia and multiple ocular abnormalities were detected in the left eye (globe deviation, corneal opacities, iridodonesis, and aphakia). A thickening of the palpebral conjunctiva affecting the medial upper eyelid with erosion of the normal eyelid margin anatomy was identified. The adnexal lesion was resected by a wedge resection and histopathology was performed. Suture breakdown 3 days postoperatively required a second surgery, where buried sutures were used. The surgical techniques and postoperative care are discussed. RESULTS The histopathology revealed mucosal hyperplasia and moderate neutrophilic and lymphoplasmacytic blepharitis. No causal organisms were identified. Following initial wound dehiscence and a modified surgical technique, the upper eyelid healed without complication and retained complete function. CONCLUSIONS The eyelid lesion involved a benign inflammatory and hyperplastic pathology of unknown etiology. Adjusting routine ophthalmic surgical techniques to wildlife and zoo animals can be challenging and complicated. It is important to understand the nature of the animals being managed, their circadian cycle, and habitat, to adjust and individualize the surgical approach, instrumentation, suture material, and perioperative treatment.

Characterization of primary pulmonary adenosquamous carcinoma-associated pleural effusion.

A 10-year-old, female spayed Shih Tzu was presented due to weight loss, increased respiratory effort and lethargy, determined to be secondary to a congenital para-esophageal diaphragmatic defect with partial herniation of the stomach and spleen. Four days following reduction surgery of the displaced abdominal organs thoracic effusion developed. Thoracic fluid evaluation revealed a cell-rich, protein-poor modified transudate with neutrophils, reactive mesothelial cells, and atypical epitheloid cells which occasionally appeared to be keratinizing, consistent with neoplastic exfoliation. Thoracic effusion recurred 2 days later, with similar characteristics as the initial sample. Computed tomography (CT) indicated consolidation and displacement of the right middle and accessory lung lobes. Exploratory thoracic surgery demonstrated a thickened, hyperemic right middle lung lobe, and thickened pericardial diaphragmatic ligament. Histologic evaluation of these tissues identified a primary pulmonary adenosquamous carcinoma with intravascular and pleural invasion. Based on these cytologic, histologic, and clinical findings, we conclude that primary pulmonary carcinomas may involve superficial thoracic structures and exfoliate into a thoracic effusion.

Nasal cryptococcoma causing severe meningitis in a dog in the UK

A five-year-old neutered male Staffordshire bull terrier was referred with a one-month history of lethargy and ataxia. Neurolocalisation was to the left forebrain with suspected increased intracranial pressure. MRI demonstrated a mass lesion in the caudal right and left nasal cavities extending through the cribriform plate into the rostral cranial fossa infiltrating the left olfactory bulb and left frontal lobe. Severe diffuse meningitis of the brain and cranial cervical spinal cord characterised by disseminated avidly enhancing meningeal nodules was present. At postmortem examination, the mass was multilobulated and firm; histologically, it was composed of pyogranulomatous and eosinophilic inflammation associated with large numbers of encapsulated yeast-like organisms, consistent with a nasal cryptococcoma. Fungal culture from a nasal swab confirmed Cryptococcus neoformans species. To the authors’ knowledge, this is the first case reported in the UK of a dog with nasal cryptococcoma causing severe meningitis.