Coil embolization of a congenital orbital varix in a dog

A 10-week-old Labrador Retriever was examined because of a swelling above the left eye. Ophthalmic examination revealed a tubular, light-pink, slightly raised lesion of the left conjunctiva that extended from the limbus to the fornix and into the dorsal eyelid. The lesion affected the entire margin of the dorsal eyelid and extended 2 cm dorsal to the eyelid margin. With compression of the left jugular vein, the exophthalmos worsened immediately and the subconjunctival and eyelid lesion enlarged. Results of ultrasonography, computed tomography, and contrast venography were consistent with a diagnosis of an orbital varix. Coil embolization was elected for treatment of the varix to prevent the pain and morbidity associated with an orbitotomy. Coils were introduced through a 22-gauge IV catheter inserted through the upper eyelid into the varix. The only complication was moderately severe orbital swelling. The owners reported that the lesion had resolved by 2 weeks after coil embolization.     

Use of an intravenous sclerosing foam (3% sodium tetradecyl sulfate) for treatment of orbital varix in a dog

A 6‐month‐old intact male Standard Dachshund was referred for evaluation of a soft tissue swelling above the right eye. Examination of the right eye revealed mild lateral deviation of the globe, normal vision, and a dorsonasal soft tissue swelling. Examination of the posterior segment was normal. Dual‐phase computed tomography angiography was consistent with an orbital varix of the angularis oculi and right dorsal external ophthalmic veins with no evidence of arterial involvement. Treatment involved fluoroscopically guided coil embolization of the venous outflow with nine platinum microcoils, followed by sclerotherapy of the varix using 1.5 mL of 3% sodium tetradecyl sulfate foam. Moderate‐to‐marked swelling was noted at the treatment site in the weeks following therapy, which gradually resolved. At final reexamination 3 months post‐therapy, complete sclerosis and resolution of the orbital varix were documented. To the authors’ knowledge, this is the first reported case involving the use of a sclerotic agent for successful treatment of a venous malformation in a dog.     

Lateral orbitotomy for treatment of an orbital abscess in a dog

A two‐year‐old Jack Russell terrier was diagnosed with a retrobulbar abscess and orbital cellulitis. The diagnosis was confirmed by ultrasound, magnetic resonance imaging examination and ultrasound‐guided fine‐needle aspiration. Transoral ventral drainage was attempted but was unsuccessful. The abscess was successfully treated by open drainage through a lateral orbitotomy. Despite the exposure of the orbital structures, the orbital soft tissues healed by second intention without further complications. The open drainage was well tolerated and resulted in immediate reduction of inflammation and pain, allowing a quick recovery. This report describes the diagnosis and, surgical management and the long‐term (3 years) follow‐up of an unusual case of orbital abscess associated with diffuse periorbital cellulitis successfully treated by open drainage through a lateral orbitotomy.     

Orbital extraskeletal osteosarcoma following enucleation in a cat: a case report

Objective We present a unique case of a feline orbital extraskeletal osteosarcoma that developed 5 years post‐enucleation. History In 2002, an ophthalmologist enucleated the left eye of a 2‐year‐old neutered male DSH and submitted it to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). COPLOW diagnosed the left eye with feline diffuse iris melanoma. In June 2007, the cat presented to another veterinarian for moderate swelling of the enucleation site. Palpation suggested a firm mass along the lateral orbital rim and an exploratory orbitotomy revealed a cyst with a mass adhered to it and the ventrolateral orbital rim. The cyst and mass were excised by the veterinarian and submitted to COPLOW. COPLOW diagnosed the tissue as an orbital conjunctival inclusion cyst and an acquired orbital osteosarcoma. Conclusions Following the enucleation, retained conjunctival epithelium became embedded in the connective tissue of the orbit and caused a cyst to develop. The cyst wall consisted of a myofibroblastic collagen‐rich matrix and acted as a nidus of chronic irritation and tumor growth. This orbital osteosarcoma resembles feline vaccine‐associated sarcomas (VAS), feline post‐traumatic ocular sarcomas, and microchip‐associated sarcomas in terms of it histopathology and its hypothesized pathogenesis related to exposure to antigenic material such as implanted epithelium, lens protein, vaccine components, and microchips as foreign bodies.     

Bilateral microphthalmos with cyst in a neonatal foal

A 1‐day–old miniature horse filly was presented to the University of Florida Veterinary Ophthalmology service for evaluation of multiple ocular anomalies which were present from birth. Protruding from the right orbit was a large, fluctuant, red, dry and variably ulcerated mass. A globe could not be appreciated clinically in the left orbit. Ocular ultrasound of both orbits was performed. This revealed a lobular, hypo‐echoic structure filling the right orbit, with multiple hyperechoic septations; normal ocular structures were not identified. Ultrasound of the left orbit revealed a microphthalmic eye, with a well‐defined, hyperechoic structure in the vitreous that was thought to be the lens. Due to irreversible blindness, the foal was humanely euthanized. Histopathology and immunohistochemistry of the orbital contents revealed bilateral microphthalmos with cyst, a congenital defect rarely reported in the veterinary literature.     

The localization of a conjunctivoscleral foreign body via high‐resolution microscopy coil magnetic resonance imaging in a dog

A 3‐year‐old French bulldog was presented to the ophthalmology service of the Vetsuisse Faculty, University of Zurich with a 3‐day history of conjunctival swelling of the left eye (OS). Ophthalmologic examination revealed a moderate conjunctival hyperemia and chemosis. A migrating foreign body having entered the conjunctival fornix behind the nictitating membrane was suspected. Within the first 24 hours of medical management, OS developed a panuveitis and a scleral perforation was highly suspected. Ocular and orbital ultrasound as well as conventional magnetic resonance imaging (MRI) examinations failed to confirm the presence of a perforating foreign body. A High‐Resolution MRI (HR‐MRI) using a microscopy coil was then performed with findings consistent with a perforating and migrating foreign body. A grass awn of 12 mm length was surgically retrieved “ab externo” from its’ point of entry into the sclera. To the best of our knowledge, HR‐MRI has not yet been used to examine canine eyes. This case report supports the idea that orbital imaging can be greatly enhanced with the introduction of HR‐MRI using microscopy coils with clinically relevant implications.     

Exophthalmos due to sterile neutrophilic dermatosis in a dog

An 8‐year‐old castrated male Bichon Frise was presented to the Kansas State University Veterinary Health Center for evaluation of unilateral right‐sided exophthalmos, suspected secondary to a retrobulbar abscess. The dog had acutely developed right‐sided periorbital swelling, exophthalmos with pain on retropulsion, as well as multiple cutaneous exudative plaques on the feet and tail base. On ophthalmic examination, the dog also exhibited mild left‐sided exophthalmos with decreased, nonpainful retropulsion. Orbital ultrasound and CT were performed to evaluate the extent of bilateral orbital disease. Incisional biopsies were obtained from the affected right periorbital tissues and skin of the feet, and histopathology revealed severe neutrophilic inflammation of the dermis with no organisms detected. Histologic changes were consistent with sterile neutrophilic dermatosis. The dog achieved clinical remission following treatment with initial immunosuppressive doses of corticosteroids and subsequent long‐term maintenance therapy using oral cyclosporine.     

Peripheral nerve stimulation under ultrasonographic control to determine the needle‐to‐nerve relationship

ObjectiveTo determine the needle‐to‐nerve distances during electrical nerve location in dogs at different currents and pulse duration using a peripheral nerve stimulator (PNS) under ultrasound control (US), and the minimal electrical thresholds (MET) necessary to obtain a motor response (MR) after achieving needle‐to‐nerve contact.Study designProspective in vivo experimental trial in a clinical settingAnimalsThirty dogs, scheduled for locoregional anaesthesia of the sciatic nerve.MethodsNeedle‐to‐nerve distance was measured ultrasonographically after obtaining the MR of sciatic nerve with 2, 1 and 0.5 mA and pulse duration 0.1 ms (NS0.1). Thereafter the needle was placed in contact with the nerve and MET was determined. The procedure was repeated with 0.3 ms (NS0.3). Finally the needle was reintroduced to contact the sciatic nerve guided only by US, thus MET‐US was determined. Data were analysed using Kruskal–Wallis or Mann–Whitney tests.ResultsNeedle‐to‐nerve distances were greater when MR was obtained with 2 mA than with 1 and 0.5 mA at 0.1 and 0.3 ms. No significant differences were observed between the needle‐to‐nerve distances using 0.1 or 0.3 ms.The MET [median (range)] was 0.4 (0.18–1.3) mA in NS0.1, 0.32 (0.12–0.8) mA in NS0.3; while MET‐US was 0.7 (0.32–1.5) mA. When the needle contacted the nerve, the MR achieved with currents below 0.3 mA was obtained in 17.2, 40 and 0% of cases using NS0.1, NS0.3 and US respectively.Conclusions and clinical relevanceThe electrical current necessary to obtain a MR decreased as the needle moved towards the nerve. However when the needle tip contacted the nerve, an MR with low current intensity could not be obtained. Thus the absence of motor response at currents below 0.3 mA cannot rule out needle‐epineurium contact. When ultrasound is combined with PNS, it is more important to assess the correct needle position than searching for an MR at low currents.     

Retrobulbar lymphoma associated with a ballistic foreign body in a cat

A seven‐year‐old domestic shorthair cat, adopted 5 years previously with a corneal perforation of the left eye, was presented for investigation of a left orbital mass. Computed tomography revealed a metallic foreign body within a contrast‐enhancing, heterogeneous orbital mass. Large cell lymphoma was diagnosed from a fine needle aspirate. The cat staged negatively and was treated with l‐asparaginase, prednisolone and three fractions of radiation therapy. A rapid clinical remission was obtained and the cat remained in remission for 3 years after therapy. This is the first report of large cell lymphoma likely occurring secondary to a foreign body.     

MAGNETIC RESONANCE IMAGING OF THE CANINE OPTIC NERVE

We describe the magnetic resonance (MR) imaging aspects of normal canine optic nerve, the diameter of the optic nerve as measured on MR images, and optimal MR sequences for the evaluation of the optic nerve using a 0.2 T MR unit. Three millimeter contiguous slides of the normal canine orbital region were acquired in transverse and dorsal oblique planes using a variety of tissue weighting sequences. It was apparent that detailed anatomic assessment of the optic nerve can be performed with low‐field MR imaging, but none of the sequences provided unequivocal superior image quality of the optic nerve. The mean diameter of the optic nerve sheath complex was 3.7 mm and of the optic nerve 1.7 mm. The intraorbital and intracanalicular parts of the optic nerve are consistently visible and differentiation between the optic nerve and optic nerve sheath complex is possible using low‐field MR systems.     

Imaging features and decision making in retrobulbar neuroendocrine tumours in horses--case report and review of literature

A 25-year-old Haflinger gelding was evaluated for chronic-progressive unilateral exophthalmos. Ultrasonographic investigation and magnetic resonance (MR) imaging revealed a retrobulbar space-occupying mass to be the cause of eyeball displacement. Ultrasonographic features were not sufficient to specify the type and extension of the lesion. Magnetic resonance scans, however, clearly displayed an infiltrative intracranial growth pattern but sparing of orbital soft tissues. Based on MR appearance, tentative diagnosis of an orbital soft tissue neoplasia was made and subsequently confirmed by histopathological investigation. The latter revealed a poorly differentiated neuroendocrine tumour. Retrospectively, MR changes resembled those seen with neuroendocrine neoplasms of the human skull. Even if histopathology remains to be elucidated by cytological or histological inspection, MR imaging of equine orbital tumours should provide the criteria necessary for evaluating the therapeutic options and associated prognosis.     

Surgical excision of a feline orbital lacrimal gland adenocarcinoma with adjunctive cryotherapy and carboplatin‐impregnated bead implantation

The purpose of this report was to discuss the diagnosis, treatment, and outcome of a cat with an orbital lacrimal gland adenocarcinoma. A 14.5‐year‐old spayed female domestic shorthair cat was evaluated for a firm swelling at the left dorsotemporal orbital rim. The orbital mass was excised with preservation of the globe, and adjunctive cryotherapy was performed. A definitive diagnosis of lacrimal gland adenocarcinoma was obtained after histopathologic evaluation and histochemical staining with periodic acid–Schiff and mucicarmine. Thirteen months postoperatively, tumor regrowth occurred with a much larger osteolytic lesion, and a second surgery was performed consisting of tumor excision with implantation of carboplatin‐impregnated calcium sulfate hemihydrate beads. The cat has remained free of recurrence 11 months after the second surgery (26 months after initial diagnosis and surgery). A feline orbital lacrimal gland adenocarcinoma was successfully managed utilizing globe‐preserving surgical excision with adjunctive cryotherapy and subsequent carboplatin‐impregnated bead implantation. Orbital lacrimal gland adenocarcinoma in cats may not be as aggressive as other forms of periocular, head, and neck adenocarcinomas.     

Ultrasound‐guided retrobulbar nerve block in horses: a cadaveric study

Objective To develop an ultrasound‐guided technique for retrobulbar nerve block in horses, and to compare the distribution of three different volumes of injected contrast medium (CM) (4, 8 and 12 mL), with the hypothesis that successful placement of the needle within the retractor bulbi muscle cone would lead to the most effective dispersal of CM towards the nerves leaving the orbital fissure. Study design Prospective experimental cadaver study. Animals Twenty equine cadavers. Methods Ultrasound‐guided retrobulbar injections were performed in 40 cadaver orbits. Ultrasound visualization of needle placement within the retractor bulbi muscle cone and spread of injected CM towards the orbital fissure were scored. Needle position and destination of CM were then assessed using computerized tomography (CT), and comparisons performed between ultrasonographic visualization of orbital structures and success rate of injections (intraconal needle placement, CM reaching the orbital fissure). Results Higher scores for ultrasound visualization resulted in a higher success rate for intraconal CM injection, as documented on the CT images. Successful intraconal placement of the needle (22/34 orbits) resulted in CM always reaching the orbital fissure. CM also reached the orbital fissure in six orbits where needle placement was extraconal. With 4, 8 and 12 mL CM, the orbital fissure was reached in 16/34, 23/34 and 28/34 injections, respectively. Conclusion and clinical relevance The present study demonstrates the use of ultrasound for visualization of anatomical structures and needle placement during retrobulbar injections in equine orbits. However, this approach needs to be repeated in controlled clinical trials to assess practicability and effectiveness in clinical practice.     

Pyometra and unilateral uterine horn torsion in a sheep

A 13‐year‐old Romanov sheep presented for evaluation of vaginal discharge, depression and anorexia. Blood work demonstrated mature neutrophilia and marked hyperlactatemia. Transrectal and transabdominal ultrasound revealed echogenic fluid (pus) within the uterus. Purulent uterine fluid culture yield Escherichia coli. A diagnosis of pyometra was made. After medical treatment without clinical improvement, an exploratory laparotomy was performed, and a 360‐degree uterine left horn torsion was identified with the pyometra and multiple corpora lutea on both ovaries. Ovariohysterectomy was performed and the ewe recovered uneventfully.     

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.     

Navicular bone osteomyelitis and navicular bursitis with associated fistula diagnosed with magnetic resonance fistulography in the horse

A 7‐year‐old Quarter Horse gelding was referred for magnetic resonance (MR) imaging due to chronic left hindlimb lameness localised to the foot. On presentation, a previously undiagnosed draining tract was identified at the plantar aspect of the pastern. Radiographs revealed severe osteolysis of the navicular bone. Positive contrast MR fistulography was performed using a gadolinium based contrast agent following conventional MR imaging of the left hind foot. Fistulography allowed characterisation of a fistulous tract, which was closely associated with the deep digital flexor tendon, navicular bursa and osteomyelitis of the navicular bone.     

FREQUENCY AND NUMBER OF ULTRASOUND LUNG ROCKETS (B‐LINES) USING A REGIONALLY BASED LUNG ULTRASOUND EXAMINATION NAMED VET BLUE (VETERINARY BEDSIDE LUNG ULTRASOUND EXAM) IN DOGS WITH RADIOGRAPHICALLY NORMAL LUNG FINDINGS

Lung ultrasound is superior to lung auscultation and supine chest radiography for many respiratory conditions in human patients. Ultrasound diagnoses are based on easily learned patterns of sonographic findings and artifacts in standardized images. By applying the wet lung (ultrasound lung rockets or B‐lines, representing interstitial edema) versus dry lung (A‐lines with a glide sign) concept many respiratory conditions can be diagnosed or excluded. The ultrasound probe can be used as a visual stethoscope for the evaluation of human lungs because dry artifacts (A‐lines with a glide sign) predominate over wet artifacts (ultrasound lung rockets or B‐lines). However, the frequency and number of wet lung ultrasound artifacts in dogs with radiographically normal lungs is unknown. Thus, the primary objective was to determine the baseline frequency and number of ultrasound lung rockets in dogs without clinical signs of respiratory disease and with radiographically normal lung findings using an 8‐view novel regionally based lung ultrasound examination called Vet BLUE. Frequency of ultrasound lung rockets were statistically compared based on signalment, body condition score, investigator, and reasons for radiography. Ten left‐sided heart failure dogs were similarly enrolled. Overall frequency of ultrasound lung rockets was 11% (95% confidence interval, 6–19%) in dogs without respiratory disease versus 100% (95% confidence interval, 74–100%) in those with left‐sided heart failure. The low frequency and number of ultrasound lung rockets observed in dogs without respiratory disease and with radiographically normal lungs suggests that Vet BLUE will be clinically useful for the identification of canine respiratory conditions.     

IMAGING DIAGNOSIS—SYNOVIAL MYXOMA OF LUMBAR VERTEBRAE ARTICULAR PROCESS JOINT

Magnetic resonance (MR) imaging and histopathology were used to diagnose an articular process synovial myxoma in a dog. On MR images, the tumor was characterized by distortion of the left L1–L2 articular process, widening of the articular process joint, and the presence of a mass contiguous with the synovium of the articular process that displaced the spinal cord. The tumor was T2‐hyperintense, T1‐hypointense, relative to muscle, and had mild contrast enhancement. The MR features of articular process synovial myxoma may be distinct from other diseases of the articular process joint.     

Successful medical treatment of an orbital osteoma in a dog

A 6‐year‐old neutered male German Shepherd‐mixed breed with a 2‐month history of bilateral conjunctival hyperemia, epiphora, and a firm, slowly progressive swelling of the medial canthal region of the left eye (OS) was examined. Ophthalmic examination OS revealed a firm and smooth mass, extending from the medial canthus toward the medial orbital wall. Indirect ophthalmoscopy revealed indentation of the nasal part OS, which corresponded to the position of the orbital mass. Orbital neoplastic diseases were the main differential considerations. Computerized tomography revealed a bony smooth orbital mass without bone destructive features. Biopsy was performed, and histologic features were suggestive of osteoma. Systemic nonsteroidal anti‐inflammatory (NSAID) drugs resulted in complete mass regression and absence of clinical signs for 5 years following initial diagnosis. This report describes the first case of canine orbital osteoma, which was responsive to NSAIDs.