Malignant transformation of an aneurysmal bone cyst in a dog

OBJECTIVE: To report malignant transformation of an aneurysmal bone cyst in a dog. STUDY DESIGN: Case report. SAMPLE POPULATION: Client-owned dog. RESULTS: A 5-year-old male Labrador retriever was diagnosed with an aneurysmal bone cyst of the distal aspect of the right ulna. Surgical curettage resulted in remission of clinical signs for 33 months. Because of recurrence of clinical signs, a distal ulnar ostectomy was performed. Histopathologic examination of the excised specimen revealed a moderately differentiated chondrosarcoma at the level of the bone cyst. Limb function was normal for 17 months until a subcutaneous mass, determined to be a chondrosarcoma, occurred at the level of the shoulder. A right forequarter amputation was performed. CONCLUSIONS: Aneurysmal bone cysts are benign but may be transformed into a malignancy after surgical manipulation. Complete surgical excision should be attempted where possible. In this case, distal ulnar ostectomy was an effective means of preserving limb function and preventing local recurrence of chondrosarcoma.     

Intrapericardial Cysts in the Dog

Intrapericardial cysts were identified as the cause of impaired cardiac filling in six young dogs. Pneumo-pericardiography and two-dimensional echocardiography showed the cysts in 2 of 2 dogs and in 4 of 4 dogs, respectively. One dog, which was also infected with heartworms, died before surgical excision of the cyst could be performed. In the remaining dogs, surgical excision of the cysts and subtotal pericar-diectomy was successfully accomplished. Histologic examination of the excised tissue from one dog suggested that it was a pericardial coelomic cyst. The gross and histologic characteristics of the cysts removed from the other five dogs resembled those of acquired cystic hematomas. The etiopathogenesis of these cysts was uncertain, but all cysts were connected to a fatty pedicle of tissue. In one dog, a stalk of tissue was observed to enter the pericardium through a small peritoneopericardial diaphragmatic hernia. In four dogs, the stalk of tissue was adhered to the apex of the parietal pericardium. These observations suggested that intrapericardial cysts, in some dogs, develop in association with, and possibly as a result of, congenital herniation and entrapment of omentum or a portion of the falciform ligament into the pericardial sac. (Journal of Veterinary Internal Medicine 1993; 7:364–369. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Arthroscopic treatment of meniscal cysts in the horse

Reasons for performing study: To describe the clinical symptoms, treatment, and outcome of meniscal cysts in horses. These structures have not been previously described in the literature as a potential cause of lameness in the horse. Hypothesis: Meniscal cysts are an uncommon condition of the femorotibial joint but can be a significant cause of lameness. Symptoms can be resolved by arthroscopic excision. Methods: Records of horses diagnosed with meniscal cysts and treated by cyst excision and meniscal debridement at 2 surgical practices were reviewed. Clinical outcome was determined by repeat veterinary examination and contact with owner. Results: Seven cases of meniscal cyst were treated with arthroscopic cyst excision and meniscal debridement. Five of 7 horses had lameness attributable to femorotibial joint pathology, while the remaining 2 horses had meniscal cysts found incidentally during diagnostic arthroscopy for the treatment of osteochondritis dissecans of the lateral trochlear ridge of the femur. Five of 6 horses with long‐term follow‐up were sound and a 7th horse was improved 11 months after surgery. Conclusions and potential relevance: Meniscal cysts, while uncommon, can be associated with progressive lameness in the horse. Surgical excision of the cysts results in resolution or improvement of symptoms, without evidence of recurrence on follow‐up examination.     

CRANIAL MEDIASTINAL CYSTS IN NINE CATS

Nine cats, from 11 to 17 years of age (mean 13.6 years of age), were diagnosed with a cranial mediastinal cyst. Thoracic radiographs in all cats were characterized by an increased soft tissue opacity in the cranial mediastinum confirmed to be a cyst by ultrasonography or necropsy. Ultrasonographically cysts appeared as an anechoic mass. A low-cellularity clear fluid was obtained on aspiration. The majority of the cats (n = 8) presented for unrelated conditions with no signs of respiratory distress. No treatment for the cyst was pursued except for drainage during ultrasonographic-guided aspiration in several cats. On follow-up of eight cats, none were symptomatic for the cyst from 3-45 months after diagnosis. Mediastinal cyst should be considered when a cranial mediastinal mass is evident radiographically in an older cat. The majority of feline cranial mediastinal cysts are benign with no need for treatment.     

Dermoid Cyst in the Intermandibular Space of a 3-Year-Old Thoroughbred Gelding: A Case Report

Soft tissue swelling located in the intermandibular space is very common in horses and presents a significant diagnostic challenge. Although the possible etiologies of intermandibular swelling are many, dermoid cysts are rarely included within the differential diagnoses list. This may be due to their low prevalence and to the lack of English written literature reporting dermoid cysts in this location in horses. This is the first report describing the clinical signs, diagnosis, and management of a dermoid cyst arising in the intermandibular space of a Thoroughbred horse. In this case, an enlarging soft tissue mass located in the intermandibular space was diagnosed as a dermoid cyst following complete subcutaneous surgical excision and histopathology.     

Evaluation of peroral transendoscopic contact neodymium:yttrium aluminum garnet laser and snare excision of subepiglottic cysts in horses

Three basic techniques (and one modified technique) were developed, allowing successful excision of subepiglottic cysts in 10 horses (5 Standardbreds, 4 Thoroughbreds, and 1 Quarter Horse; mean age, 3.5 years) via peroral approach. This approach eliminated the need for laryngotomy or pharyngotomy and reduced postoperative care. None of the cysts redeveloped. Clinical signs of disease before surgery included respiratory noise, exercise intolerance, coughing, and dysphagia and were eliminated in all horses except one that raced successfully, but in which some respiratory noise was detected. Peroral subepiglottic cyst excision was performed on anesthetized horses that were positioned in lateral recumbency and intubated via the nares and trachea. General anesthesia allowed careful intraoral palpation and endoscopic visualization of the oropharynx on a television monitor. Custom-designed instruments, including a guide tube, cyst snare, and long grasping forceps, facilitated either laser or snare, or laser and snare cyst excision. Hemorrhage was negligible in all horses. Initial attempts to develop a technique to submucosally excise subepiglottic cysts through a transnasal transendoscopic approach in conscious horses, using a contact neodymium:yttrium aluminum garnet laser, were unsuccessful. In each of 3 horses, the cyst was inadvertently penetrated before it could be excised, causing it to collapse and disappear beneath the soft palate. Postoperative complications were excessive subepiglottic swelling after laser excision (n = 1 horse), which resolved completely in response to anti-inflammatory treatment, and subepiglottic cicatrix formation after snare excision (n = 1 horse), which required surgical excision of the cicatrix.     

Congenital orbital cysts of neural tissue in two dogs

A 3-month-old English Cocker Spaniel and a 6-month-old miniature poodle presented with clinical signs related to an abnormal right eye since birth. In both dogs, the right globe could not be identified and was replaced by a fluctuant intraorbital mass covered by a vascularized mucous membrane. Ultrasonography demonstrated that both masses were cystic structures markedly larger in size than the normal contralateral globes. In both cases, surgical excision revealed a multilobular cyst filling the whole orbital cavity. Histopathologic examination and immunostaining for glial fibrillary acid protein and S100 protein supported a diagnosis of neural cysts associated with ocular dysplasia. The definitive diagnosis was congenital cystic eye and microphthalmos with cyst for the Cocker Spaniel and miniature poodle, respectively. Karyotype was normal in both dogs. Congenital cystic eye and microphthalmos with cyst result from defects in early embryonic life that arise following formation of the optic vesicle and prior to closure of the optic fissure. To the authors' knowledge neither has been reported in the canine species. They should be considered in the differential diagnosis of orbital cysts in dogs.     

Surgical Treatment of Intramural Esophageal Inclusion Cysts in Three Horses

Three horses were diagnosed as having esophageal inclusion cysts. Clinical signs included dysphagia, swelling of the cervical esophagus, and salivation. Surgical removal of the cyst was attempted in two horses. Both horses survived, but multiple complications occurred, including esophageal fistulation and neurovascular damage. Marsupialization of the cyst was performed in the third horse. The stoma closed 3 weeks after surgery without complications, and endoscopic examination revealed a grossly normal esophagus. Marsupialization may be preferable to surgical removal for treatment of selected esophageal inclusion cysts in horses.     

Caudal mediastinal thyroglossal duct cyst in a cat

An eight-year-old domestic shorthair cat was evaluated because of dyspnoea secondary to pleural effusion. Ultrasound examination identified a large anechoic cyst-like structure in the caudal thorax. A median sternotomy was performed, and the cystic mass was removed. Microscopically, the excised tissue was identified as a multilocular thyroglossal duct cyst with ectopic thyroid tissue. To the authors' knowledge, this is the first report of a mediastinal thyroglossal duct cyst in a cat. Despite the rarity of this lesion, it should be considered when a cystic thoracic structure is identified on thoracic ultrasound. Surgical excision of the cyst resulted in complete resolution of the pleural effusion and clinical signs.     

Spinal arachnoid cyst in four dogs: diagnosis, surgical treatment and follow-up results

Spinal arachnoid cysts were diagnosed in four dogs; two schipperkes and two rottweilers. Myelography showed the cysts to be localised either at the second to third caudal vertebrae or between the eighth and tenth thoracic vertebrae. The cysts were drop-shaped with a dorsal midline localisation, intradural in the arachnoid space, and with a cranial opening. Surgical treatment was performed by one of two techniques; durotomy with drainage or durectomy with resection. As the pathological examination in one case revealed a lining of hyperplastic pia-arachnoid meningothelial cells in the cyst, it was assumed that the cyst originates from a developmental disturbance during formation of the arachnoid membrane. Follow-up studies were carried out from 10 months to four years postoperatively and revealed that there were no further problems in three out of four of the dogs during this period.     

Surgical excision of a dentigerous cyst containing two dental structures

Dentigerous cysts have been described in most domestic species and man. Horses commonly present with a swelling over the temporal region and a draining tract along the proximal pinna. Dentigerous cysts are benign structures, but pose a cosmetic problem and are commonly removed by surgical excision at an early age. This case report describes a horse with a dentigerous cyst that contained 2 easily identifiable dental structures, radiographically and grossly resembling a permanent tooth and its deciduous precursor.     

Intrapericardial cyst causing cardiac tamponade in a cat

A two-year-old cat with episodic dyspnea was diagnosed with an intrapericardial cyst via two-dimensional echocardiography. The cyst directly compressed the right ventricle, resulting in cardiac tamponade. Centesis of the cyst was performed to reduce tamponade prior to surgery. At surgery, a large, fluid-filled cystic structure was found within the pericardium. The cystic structure was continuous with a pedicle of liver that passed through a small peritoneopericardial diaphragmatic hernia. Surgical resolution was achieved by median sternotomy, midline pericardotomy, resection of the cyst, and diaphragmatic herniorrhaphy.     

Corneal epithelial inclusion cyst in a Llama

A 13-year-old, female Llama presented for evaluation of a limbal based corneal mass involving the OD of 4 months duration. The mass was excised en bloc by a nonpenetrating keratectomy, followed by placement of a conjunctival advancement flap covering the keratectomy site. The mass was submitted for histological evaluation. Histopathology identified the mass to be a corneal epithelial inclusion cyst filled with necrotic squamous and neutrophilic debris. Surgical excision was complete and considered curative with no signs of recurrence 3 months postoperatively. There was no known prior ocular trauma; however, a previously performed corneal biopsy for evaluation of recurrent epithelial erosions may have been an initiating cause.     

Synovial cysts associated with cauda equina syndrome in two dogs

OBJECTIVE: To report synovial cysts associated with cauda equina syndrome in 2 dogs. STUDY DESIGN: Clinical cases. ANIMALS: Two German Shepherd dogs. METHODS: After magnetic resonance imaging detection, cysts were surgically removed via dorsal laminectomy. RESULTS: Six and 8 months after surgery, both dogs were free of clinical signs and no pain was elicited on lumbosacral joint manipulation. CONCLUSION: Although described in dogs, cysts at the lumbosacral joint might cause compression of the cauda equina nerve roots. Radical excision of the cyst capsule can result in resolution of clinical signs. CLINICAL RELEVANCE: Synovial cysts should be considered in the differential diagnosis of dogs with cauda equina compression syndrome when lumbosacral degenerative joint disease is present.     

一例法斗犬眼角膜皮样囊肿切除及结膜瓣遮盖术

角膜皮样囊肿是一种长在人或动物的角膜、结膜、角巩膜等处被覆毛发的异常皮肤样组织。在人和动物均可见,动物中尤其是在牛和犬中较为常见。角膜皮样囊肿可以引发眼睑痉挛、眼分泌物增加、结膜炎、角膜炎和角膜溃疡等,严重者可导致角膜穿孔和眼球坏死。通过角膜切除术或结膜切除术,切除角膜皮样囊肿并对症治疗的方法来治疗眼部角膜皮样囊肿。以下是在2022年3月接诊的一例幼年法斗犬患有右侧眼角膜皮样囊肿,对患犬实施浅层角膜切除术切除右侧角膜皮样囊肿并用结膜瓣遮盖的手术方法进行治疗,术后恢复良好。     

Marsupialization and iodine sclerotherapy of a branchial cyst in a horse

A 6-month-old Morgan colt was evaluated because of a 10-cm right-sided retropharyngeal swelling. The swelling was soft and moveable on examination, and palpation did not elicit signs of pain. Radiography revealed a large space-occupying mass ventral to the second cervical vertebra; ultrasonography revealed an anechoic fluid-filled structure with a well-defined hyperechoic capsule. Fine-needle aspiration yielded a viscous amber fluid. Cytologic evaluation indicated that the fluid was an exudate; anaerobic and aerobic bacterial culture did not yield any growth. Histologic examination of a portion of the cyst capsule revealed a connective tissue wall lined by pseudostratified columnar to cuboidal epithelium, consistent with a branchial cyst. The cyst wall was marsupialized to the skin, and iodine sclerotherapy was performed twice daily for 14 days, at which time forceps were introduced into the cyst and the cyst lining was removed. The site was allowed to heal by second intention, but 10 days later, the swelling recurred. An incision was made over the previous marsupialization site, and residual remnants of the cauterized cyst lining were removed with a forceps. The foal did not have any other complications during the subsequent 2 years. Branchial arch cysts are uncommon embryonic anomalies of horses, mice, cats, dogs, and cattle. Results suggest that marsupialization and iodine sclerotherapy may be a viable alternative to surgical excision in horses with branchial cysts; however, the entire cyst lining must be removed at the completion of sclerotherapy to prevent recurrence and abscess formation.     

Mineralized paraprostatic cyst as a potential contributing factor in the development of perineal hernias in a dog

Perineal hernias almost exclusively affect male dogs (sexually intact or castrated). Factors that may contribute or predispose a dog to perineal hernias include tenesmus, pelvic musculature variations (male vs female), and gonadal hormone influence. In dogs with perineal hernias and tenesmus it is important to include rectal and prostatic diseases, including paraprostatic cysts, in the differential list of potential underlying causes. Surgical correction of the perineal hernia with a perineal herniorrhaphy is indicated. Successful treatment depends on the degree of preexisting neurologic alterations, meticulous surgical technique, and identification and correction of underlying contributing factors. Paraprostatic cysts develop predominantly in sexually intact medium to large breed dogs. These cysts are thin-walled structures often attached to the prostatic dorsal midline. Osseous metaplasia of paraprostatic cysts may occur. Clinical signs of tenesmus often result from compression on adjacent structures (urinary bladder and colon), and tenesmus may contribute to the development of perineal hernias. Preferred treatment of a paraprostatic cyst is surgical removal and castration. This report describes a dog with bilateral perineal hernias and a large mineralized paraprostatic cyst that was identified as a possible contributing factor to the hernias.     

Branchial remnant cysts of mature and juvenile horses

This clinical report describes 8 cases of branchial remnant cysts (BRC) in the horse. The horses presented with bimodal age distribution, with 5 cases in mature horses (age 8–21 years) and 3 in foals (age 1, 6 and 10 months). Mature cases presented for dysphagia or intermittent oesophageal obstruction (2/5), and retropharyngeal swelling (3/5), whereas respiratory stridor and visible mass were presenting complaints in the foals. Presence of a right‐sided (5/8) or dorsally located (2/8) palpable retropharyngeal mass of 3–35 cm diameter was noted clinically; one left‐sided mass was identified as an incidental finding at necropsy. Ultrasonography typically revealed a thick‐walled cyst containing hypoechoic fluid with dependent hyperechoic masses consistent with blood clots. Radiographs and upper airway endoscopy were also consistent with a retropharyngeal mass. Fluid cytology revealed chronic haemorrhage in 6/8 cases, and squamous epithelial cells in one case. Histopathology in all cases demonstrated an epithelium‐lined cyst with no smooth muscle or thyroid tissue. Two cases was subjected to euthanasia; one due to concurrent laryngeal anomalies and one due to financial constraints. The remaining 5 cases were treated via surgical excision. Post operatively, right laryngeal hemiplegia was observed in 4/5 cases. All previous reports of BRC in the horse have described juvenile individuals. Brachial remnant cyst should be considered a differential diagnosis for mature horses with masses of the throatlatch area and can be definitively diagnosed by the presence of squamous epithelium in aspirated fluid or by histopathology of the excised mass. Right recurrent laryngeal nerve damage is a common complication of surgery.     

The diagnosis and management of paraprostatic and prostatic retention cysts in the dog

Eleven dogs were diagnosed as having solitary or multiple prostatic cysts in an abdominal, pelvic or perineal position. Common presenting signs included urinary dysfunction, faecal tenesmus and abdominal distension. Cystography was found to be the most consistently accurate technique for differentiating the cysts from the bladder and other abdominal soft tissue masses whilst urethrography often highlighted their prostatic origin. Complete surgical resection of the cysts was attempted in nine dogs, the complexity of dissection being dictated by cyst size and the extent of adhesions to adjacent organs. Nine dogs were castrated. Urinary incontinence continued post-operatively in four dogs but later resolved in three of these. Seven dogs were alive and symptom-free over post-operative periods ranging from one to three years. Despite some of its technical difficulties, surgical excision appears to be a successful approach to even the larger prostatic cysts. Few of the post-operative complications associated with other surgical procedures described for the management of cysts were encountered.