Maxillary bone epithelial cyst in an adult miniature schnauzer

Maxillary bone epithelial cyst is rare in dogs. A 5-year-old, spayed female miniature schnauzer developed a swelling below the nasal canthus of left eye. Plain radiograph demonstrated a 1.5 cm diameter of radiolucent lesion on the maxillary bone anteroventral to the eye, and contrast dacryocystorhinography confirmed an obstructed nasolarcrimal duct. The swelling showed poor response to antibiotic treatment but responded well to oral prednisolone. Exploratory surgery revealed a cyst-like structure filled with brown serous fluid. Histopathological examination of the removed cyst revealed a double cuboidal epithelial cyst. The dog recovered rapidly after surgery, and the swelling had not recurred for a 36-month follow-up. It is the first case of periorbital bone epithelial cyst reported in an adult miniature schnauzer.     

Radiographic diagnosis of an expansile bone lesion in a dog

An old dog had an expansile lesion affecting the ulnar diaphysis. The lesion had clinical and radiographic features typical of a bone cyst; however, computed X-ray tomography indicated that the lesion had a tissue content incompatible with a true cyst. The histological diagnosis was osteosarcoma. This report emphasises the highly variable radiological appearance of canine osteosarcoma; biopsy is required to establish the diagnosis because the radiological signs may mimic a lesion of different aetiology.     

Differential diagnoses,investigation, and management of a periocular swelling close to the nasolacrimal duct in a horse – A case report of Dacryops

To describe the differential diagnoses, investigation, and management of a periocular swelling close to the nasolacrimal duct in a horse that was consistent with a nasolacrimal duct dacryops (lacrimal cyst). A 16‐year‐old gelding, Connemara cross presented with a history of a periocular swelling rostroventral medial to the right eye that had been sampled by the referring veterinary surgeon. A cystic lesion was diagnosed following standing computed tomography. Surgical removal of the cystic lesion was performed, and the tissue was submitted for histopathologic and immunohistochemical examination. Surgical removal of the cyst was curative, and there was no recurrence of clinical signs 7 months later. There was a small amount of mineralized material in the center of the cyst. Histopathologic and immunohistochemical examination confirmed a nasolacrimal duct cyst. Dacryops can form in horses as well as other species and appears to have a favorable outcome if surgically removed.     

Dacryops of the lacrimal gland in a dog

A case of congenital lacrimal cyst or dacryops of the lacrimal gland in an 8‐month‐old Neapolitan Mastiff dog is reported. The dog presented with a swelling dorsolateral to the left globe, which had been present since birth. In addition, hyperplasia and prolapse of the superficial gland of the left nictitating membrane, and bilateral macropalpebral fissure and ‘diamond eye’ conformation were apparent. On manual eversion of the upper eyelid, a subconjunctival mass was visible that was translucent and pink and affected the upper conjunctival fornix. B‐mode ultrasonography revealed the presence of an echolucent thin‐walled cystic structure measuring 15 by 12 mm and containing an echodense border and a distended tubular fluid‐filled structure that extended posteriorly. A viscous and transparent fluid was aspirated from the lesion. Surgery was performed to excise the lesion, reposition the nictitans gland, and correct the morphology of the palpebral fissure. Histopathology confirmed the mass to be a cyst and distended duct of the lacrimal gland. Although tear secretion was compromised, resection of the cyst was curative.     

Ganglion cysts in a juvenile dog

Ganglion cysts were diagnosed in a 4-month-old male Afghan Hound. Grossly, the subcutaneous ovoid cysts around the caudal right elbow joint and left ischiatic tuberosity had abundant mucinous fluid and internal folding. The lesions recurred twice around the elbow joint after surgical removal. Neither cyst communicated with the joint cavity. Histologically, the cyst wall consisted of inner myxomatous and outer immature connective tissue. Some parts of the cyst wall had various stages of myxoid metaplasia of collagen tissue leading to new cyst formation. Ultrastructural study revealed that cells in the myxoid metaplastic lesion had well-developed cytoplasmic secretory elements, including abundant rough endoplasmic reticulum, Golgi apparatus, and many smooth-walled vesicles. These ganglion cysts apparently resulted from the metaplasia of fibroblasts to secreting cells.     

Endocarditis caused by Corynebacterium sp in a dog

Mitral valve bacterial endocarditis, caused by Corynebacterium sp, was diagnosed in a dog. The bacteria had characteristics unlike those commonly recognized for most species of Corynebacterium. The primary source of bacteremia was suspected to be a pilonidal cyst of the sacrum. The dog was treated with a first-generation cephalosporin for 6 weeks, and the pilonidal cyst was surgically removed. Physical examination 1 year after initial examination revealed no abnormalities other than a cardiac murmur. On echocardiographic examination 1 year after treatment, the vegetative lesion was still present; however, chamber dimensions had returned to normal. Wall thickness and contractility remained increased.     

IMAGING DIAGNOSIS—DEGENERATIVE INTRASPINAL CYST ASSOCIATED WITH AN INTERVERTEBRAL DISC

A 6-year-old neutered male Rottweiler had chronic episodic signs of thoracolumbar pain and inability to stand that did not improve after rest and nonsteroidal antiinflammatory medication. In magnetic resonance images, an extradural mass was identified between the spinal cord and the T13/L1 intervertebral disc; the mass was compressing the cord in a dorsoventral direction. The lesion had a low signal intensity rim that enhanced slightly after gadolinium administration, and contents with similar signal intensity to cerebrospinal fluid. The lesion was removed surgically by severing its attachments to the annulus fibrosus. The histologic diagnosis was degenerative intraspinal cyst. The origin of such cysts, and their relationship to synovial and ganglion cysts is discussed.     

Multiloculated solitary (unicameral) bone cyst in a young dog

A 20‐month‐old female spayed Staffordshire Terrier (22.3 kg) presented to the Orthopedic Surgery Service at North Carolina State University Veterinary Teaching Hospital for evaluation of a 6‐week history of toe‐touching to nonweight‐bearing lameness in the right hind limb. Radiographs of the right stifle revealed a multiloculated lytic lesion of the distal femur, with a large open lytic zone centrally, numerous osseous septations peripherally, and focal areas of cortical thinning and loss. An aspirate of the right distal femoral lesion yielded mildly cloudy serosanguineous fluid. Cytologic examination of the fluid revealed a pleomorphic population of discrete cells that exhibited marked anisocytosis and anisokaryosis and a variable nuclear‐to‐cytoplasmic (N:C) ratio, which were interpreted as probable neoplastic cells, with few macrophages, and evidence of hemorrhage. Given the clinical signs of pain, lesion size, and concern for malignant neoplasia, amputation of the right hind limb was performed. Histologically, the lesion had undulating walls 1‐3 mm thick with a continuous outer layer of dense fibrous tissue and an inner layer composed of reactive cancellous bone with no cortical compacta remaining. Remnants of thin fibrous or fibro‐osseous septa projected from the bony wall into the cyst lumen. The final histologic diagnosis was a benign multiloculated solitary (unicameral) bone cyst of the distal right femur. Based on the histopathologic findings, it was speculated that the cells identified on cytology were a mixture of developing osteoclasts, osteoblasts, endothelial, and stromal cells. This is the first report describing the cytologic examination of a solitary bone cyst in veterinary medicine.     

Dermoid cyst of the spinal cord associated with ataxia in a cat

A young adult Balinese cat developed complete hindlimb paralysis which persisted for six weeks. Clinical findings suggested a lesion compressing the spinal cord and this was confirmed at necropsy. A dermoid cyst was present at the level of the third thoracic vertebra. The cyst was lined by stratified squamous epithelium and contained desquamated keratinised material and hair fragments. Sebaceous glands and hair follicles were present in the connective tissue wall. This is the first report of a dermoid cyst in the spinal cord of a cat. The lesion is considered to be a congenital anomaly.     

IMAGING DIAGNOSIS — INTRACRANIAL EPIDERMOID CYST IN A DOBERMAN PINSCHER

A 4-year-old Doberman Pinscher was evaluated for chronic progressive central vestibular disease and aggressiveness. A cyst-like lesion was identified in the region of the left cerebellopontine angle. The lesion was hypointense on T1-weighted and hyperintense on T2-weighted images. Differentials included an epidermoid or dermoid cyst, cystic neoplasm, and brain abscess. Hyperintensity on subsequent fluid-attenuated inversion recovery images excluded an arachnoid cyst. The histopathologic diagnosis was epidermoid cyst within the fourth ventricle.     

Orbito-nasal cyst in a young European short-haired cat

Purpose To describe a case of an orbito‐nasal cyst in a cat. Procedure An 18‐month‐old male European short‐haired cat was presented to the Ophthalmology service of the Vetsuisse Faculty, University of Zurich for a subcutaneous swelling in the medial canthal region of the right eye (OD). Ophthalmologic, ultrasound and CT examinations, and fine needle aspiration were performed. After lesion excision, the removed tissue was submitted for histopathology. CT examination was repeated 5 months after removal of the cyst. Results Ophthalmologic examination revealed a large fluctuant swelling inferonasal to OD. Despite patent lacrimal puncta, only the first few mm of the lacrimal canaliculi could be cannulated. A normal globe with moderate enophthalmos was present. Ultrasound examination showed a well‐defined lobulated cyst‐like structure in the right orbit, inferonasal and anterior to the eye. CT examination revealed extension of this lesion through the medial orbital wall into the right nasal cavity. Fine needle aspiration confirmed the cystic nature of the lesion. An orbito‐nasal cyst was diagnosed. The orbital part of the cyst was dissected from the surrounding tissue and excised from the periosteum in the medial orbital wall defect. Part of the maxillary bone was removed to allow removal of the cyst from the nasal cavity. Histologically, the cyst wall consisted of a single to multilayered, mostly cuboidal epithelium and surrounding connective tissue. Follow‐up revealed a good functional result and no recurrence 7 months after cyst removal. Conclusions Similar orbito‐nasal cystic structures were reported in dogs but not in cats.     

An unusual cyst‐like lesion in the metaphysis of the tibia in a horse

A 6‐year‐old Haflinger gelding was presented with a chronic right hindlimb lameness. Scintigraphy, radiography and computed tomography confirmed an active large cyst‐like lesion in the distal metaphysis of the right tibia. A transcortical surgical approach was used to curette the lesion and fill it with an autologous bone graft and a calcium phosphate bone substitute material. Histopathology revealed mild histiocytic inflammatory changes, mild fibrosis and bone necrosis. This case report describes an unusual cyst‐like lesion in the tibial metaphysis of a horse.     

Unilateral facial paresis secondary to a suspected brainstem arachnoid cyst in a Maltese dog

An 8-year-old, intact female Maltese dog was presented with decreased tear production and unilateral loss of eye blinking. Neuro-ophthalmic examination and brain magnetic resonance imaging were performed to determine the origin of facial paresis. A cystic lesion in the left pontomedullary region which displayed equal intensity to cerebrospinal fluid was revealed. Hyposignality was noted on fluid attenuated inversion recovery sequences, and the lesion was suggestive of an arachnoid cyst. This report described unilateral facial nerve dysfunction that resulted from a suspected brainstem arachnoid cyst in an unusual anatomic location.     

Intramedullary epidermoid cyst in the thoracic spine of a dog

A 5 yr old female spayed mastiff was evaluated for a 3-4 mo history of paraparesis and 3 days of acutely worse paraparesis and incontinence. On magnetic resonance imaging, a spinal cord lesion was present at the ninth thoracic vertebra. The lesion was hyperintense on T2-weighted images (T2-W), and a hyperintense rim was present on T1-weighted postcontrast images. Histologic examination showed a cystic mass lined by squamous epithelial cells. Histopathologic diagnosis was an intramedullary epidermoid spinal cyst. Epidermoid cyst should be a differential diagnosis in young dogs with a myelopathy and an intramedullary spinal cord lesion on magnetic resonance imaging examination.     

Partial surgical removal of an intramedullary epidermoid cyst from the spinal cord of a dog

An intramedullary space-occupying lesion in the form of an epidermoid cyst was diagnosed in a one-and-a-half-year-old flat-coated retriever. Dorsal laminectomy and durotomy were performed in order to establish the diagnosis followed by excision of one third of the cyst. The remaining cystic tissue that was intimately attached to the spinal cord parenchyma was left in place in order to avoid further damage to the nervous tissue. The dog's neurological status improved dramatically after the surgery, but deteriorated four months later due to recurrence of the cyst.     

Congenital lymphangiomatosis and an enteric duplication cyst in a young dog

A two‐year‐old female poodle with abdominal distention was diagnosed with concurrent enteric duplication cyst and lymphangiomatosis. Both lesions were shown as cystic structures, but some characteristic features of enteric duplication cyst were identified including a thick cyst wall and shared blood supply with the duodenum. Although it was challenging to discriminate between the types of cyst based on diagnostic imaging, this report describes the characteristics of each type of lesion using several different imaging modalities.     

Cystic Meningiomas in 2 Dogs

Two dogs with signs of forebrain disease had hypodense lesions on computed tomography evaluation. Magnetic resonance imaging of the first dog showed a hypointense lesion on the T1-weighted scan and a hyperintense lesion on T2-weighted scanning. At surgery, both dogs had a primary cystic intracranial lesion, and the abnormal tissue adjacent to the cyst had histological features of meningiorna. Each dog underwent whole brain irradiation after surgery, and 1 dog lived for 3 years after treatment. While uncommon, meningioma should be considered as a differential diagnosis in dogs with cystic intracranial lesions. J Vet Intern Med 1996;10:72–75. Copyright © 1996 by the American College of Veterinary Internal Medicine .     

Multiple cystic intestinal duplications in a cat

A 7-year-old, female European shorthair cat with a history of recurrent vomiting had a 2-cm cystic mass in the midjejunum. Cross-sectioning and histology revealed 3 separate cystic structures in the muscular layer, in addition to a regularly structured intestinal lumen. One cyst had a 3-layered wall consisting of a dysplastic mucosa, a regularly structured submucosa, and partly double-layered muscularis that sporadically contained neurons resembling a myenteric plexus. The remaining 2 cysts had similar structures except for granulation tissue lining the lumen. The lesion was diagnosed as multiple cystic duplications in the midjejunum, which is unknown to the veterinary literature to date.     

CHOROID PLEXUS CYST IN A DOG

A 6-year-old male Doberman Pinscher had a 2-month history of dysequilibrium. Lesion localization was determined to be the cerebellomedullary pontine angle. In computed tomographic images, a well-defined, circular, hypoattenuating mass was visible at the cerebellomedullary pontine angle. The lesion, which was isoattenuating to cerebrospinal fluid, was 4 x 8 mm in diameter. Peripheral ring enhancement was evident after contrast medium administration. A choroid plexus cyst was diagnosed histopathologically.