Heterotopic polydontia as a cause for a cystic lesion in the paranasal sinus of a Thoroughbred filly

A 1-year-old Thoroughbred filly with left bony facial distortion was diagnosed with a multilobar expansile mass within the caudal maxillary and frontal sinuses on computed tomography (CT). Typical findings associated with a sinus cyst, including expression of amber fluid from the mass and a thick lining that could be peeled from the sinus walls, were found on surgical exploration of the sinus under general anaesthesia. Histological examination of firm structures within the fluid-filled cyst contained all components of embryologically normal dental tissue. The filly recovered well and entered training to race as a 2-year-old, as remodelling of the bony distortion and narrowing of the nasal passage was sufficient for airflow. Previous reports of paranasal cystic lesions in horses suggest developmental abnormalities as a causative factor, especially in young horses. Furthermore, heterotopic polydontia is reported as the underlying aetiology in some human paranasal sinus cysts. While polydontia has been reported in the paranasal sinuses and nasal passages of horses, this is the first case report that finds them associated with a cystic lesion within the paranasal sinus.     

Subchondral bone cyst of the apical portion of the proximal sesamoid bone as a cause of severe lameness in a Warmblood filly

A 20‐month‐old Warmblood filly was evaluated for acute onset of a nonweightbearing lameness and swelling of the left hindlimb. Clinical and lameness evaluation and diagnostic intrasynovial anaesthesia isolated the lameness to the left hind metatarsophalangeal region. Radiography and ultrasonography revealed a subchondral cystic lesion of the apical portion of the lateral proximal sesamoid bone associated with oedema and synovial effusion of the metatarsophalangeal joint. Arthroscopic surgical debridement of the subchondral cystic lesion resulted in immediate post operative improvement in the lameness score. Rest and controlled exercise achieved complete resolution of the lameness with the filly being able to start training without apparent lameness. Subchondral cystic lesions of the proximal sesamoid bones can be a cause of nonweightbearing lameness. Surgical debridement resulted in complete resolution of the lameness with a favourable outcome in this case.     

Rupture of a penile artery and erectile body. An uncommon cause of dysuria in a horse

In this case report, we describe the clinical features and treatment of a Thoroughbred gelding presented for dysuria caused by rupture of a penile artery, with subsequent tear to the bulbospongiosus muscle and corpus spongiosum due to suspected blunt force trauma.     

Mastitis in a neonatal filly

Neonatal mastitis is a rare occurrence in the horse. This report documents a case of mastitis caused by an organism within the Streptococcus dysgalactiae group in a 1-week-old Paint filly.     

Lymphocytic enteritis in a filly

A yearling Hanoverian filly had intermittent colic for 6 weeks, chylous peritoneal effusion, and a firm mass palpable per rectum. Exploratory laparotomy revealed mesenteric lymphadenopathy, adhesion of the mesenteric root to the duodenum and jejunum, distention of the mesenteric veins and lymphatic vessels, and increased jejunal venous pressure. Lesions in the duodenum, jejunum, and colon included infiltration of lymphocytes and plasma cells in the lamina propria.     

Lymphosarcoma in a thoroughbred filly

A case of lymphosarcoma in an month-old thoroughbred fillyis described. The course of the disease extended over 3 weeks. The initial symptom was swelling in all limbs. The terminal symptoms were dominated by congestive heart failure and respiratory distress, both being the direct result of invasive neoplastic tissue. Lymphoblasts were seen in smears but total whitecells remained within normal limits. Large tumours were present in all the major organs except the liver.     

Systemic lupus erythematosus in a filly

Systemic lupus erythematosus (SLE) was diagnosed in a 2-year-old Standardbred filly. Clinical signs of SLE included weight loss, bilateral symmetric alopecia, seborrhea, oral ulceration, and lymphadenopathy. Abnormal laboratory findings included a Coombs test-positive hemolytic anemia and positive antinuclear antibody test result. Histologic evaluation of multiple skin biopsy specimens revealed interface dermatitis with linear deposition of IgG at the basement membrane zones of the epidermis and hair follicles. The filly did not respond to glucocorticoid treatment and was euthanatized. Necropsy findings included membranous glomerulonephritis and fibrous synovitis. On the basis of these findings, SLE should be considered in the differential diagnosis of immune-mediated skin disease in horses. Definitive diagnosis of SLE relies on recognition of multisystemic disease and confirmatory histopathologic and immunopathologic findings.     

Urinothorax in a Quarter Horse filly

An 18 h old Quarter Horse filly, while being treated for diarrhoea, was evaluated for a distended abdomen and electrolyte abnormalities. Peritoneal and pleural fluid was detected by ultrasound and a presumptive diagnosis of a ruptured bladder was made. Intravenous fluid therapy was instituted to correct the electrolyte abnormalities prior to surgical repair of the bladder tear. Anaesthetic complications included hypoxaemia and decreased compliance secondary to the pleural effusion; therefore, a thoracocentesis was performed. Analysis of the pleural fluid revealed a pleural fluid to serum creatinine ratio of >1.0, indicative of urinothorax. The filly recovered from anaesthesia and was discharged on systemic antimicrobials. Urinothorax should be considered in cases of uroperitoneum with concurrent pleural effusion. Early detection may decrease patient morbidity and anaesthetic complications.     

Congenital odontogenic keratocyst in a filly

This report describes a congenital odontogenic keratocyst in the left mandible of a filly. A definitive diagnosis was only made after histopathological examination. Mandibular cysts of odontogenic and osteogenic origin have been reported in the past but a case of a keratocyst has not been previously reported in the horse.