Subependymal Reaction Secondary to Choroid Plexus Papilloma in a Horse

Choroid plexus papilloma (CPP) is a rare, benign, intracranial neoplasm. The present report described a choroid plexus papilloma of the fourth ventricle with unusual proliferative reaction of ependymal/subependymal cells in a stallion. A single, soft neoformation, red-gray in color, with an irregular surface, resembling a cauliflower, expanding from the fourth ventricle to the cerebellar peduncles was observed. Microscopically, the neoformation was composed of a single layer of simple cuboidal to columnar epithelium with a well-vascularized papillary-arboriform pattern. Multifocal subependymal aggregates forming rosettes were observed near the mesencephalic aqueduct (MA). Glial-fibrillary-acidic-protein (GFAP) was markedly positive only in the neuropil adjacent to the proliferative areas of the MA. Ependymal/subependymal reactions secondary to CPP have never been described in equine or human neuropathology. The capabilities of ependymal cells to regenerate and eventually proliferate are controversial and unclear and, thus, require additional investigation to understand the adaptive mechanisms of this rare pathogenic condition.     

Myofibroblastic Sarcoma in the Limb of a Horse

A case of myofibroblastic sarcoma in the left hind limb is reported in a 4-year-old male, mixed-breed horse. This report includes the clinical signs, macroscopic and microscopic lesions, and the immunohistochemical findings related to this neoplasm.     

Alopecia Universalis in a Horse

Abstract— Alopecia universalis was diagnosed in a 3-year-old brown Percheron mare. Clinical and histo-pathologic findings in this previously unreported condition in the horse are described.     

Carotenodermia in a Horse

This case report describes an 11-year-old Appaloosa gelding that was examined because of yellow–orange tinting of the skin of the muzzle, eyelids, sheath, anus, and perianal region without discoloration of the sclera or mucus membranes. The horse was reported to preferentially eat dandelions which were plentiful in the pasture. Physical examination was normal, except for the discolored skin. A serum chemistry panel was normal. Carotenodermia was suspected. Serum carotenoid concentrations were higher in the affected horse as compared with concentrations in two horses with depigmented skin of normal color that were on grass pasture in the same geographic area. The horse remained systemically healthy and the abnormal skin color had almost disappeared when he was examined 7 weeks later. Carotenodermia can occur in horses and can be differentiated from jaundice because the sclera remains unaffected. Veterinarians should be aware that the condition is benign and spontaneously resolves after stopping carotenoid intake.     

Surgical Management of the Trauma-Induced Colocutaneous Fistula in a Horse

There are few published reports of equine enterocutaneous fistulae, and they are almost always related to umbilical hernias. Colocutaneous fistula as a result of a penetrating wound has not been reported in horse. In this case report, surgical treatment of a traumatic colocutaneous fistula in an 8-year-old stallion is described. Under inhalation anesthesia, the fistula was removed completely, and the resultant defect on the left ventral colonic wall was closed. The defect of abdominal wall was closed routinely. The horse regained his previous performance, and no surgical complication was observed at 1 year’s follow-up.     

Pemphigus Foliaceus in a Horse

Abstract— A 3-year-old gelding was presented with a generalized chronic dermatitis characterized by erosions, ulcerations, crusting, scaling and widespread alopecia. The diagnosis of pemphigus foliaceus was based on history, clinical signs, histological lesions and immunohistological test results. Typical dermatohistopathological findings comprised intraepidermal acantholysis and cleft formation in both epidermis and hair follicle epithelium. Additionally, blisters and erosive lesions were found in the epithelia of various mucocutaneous junctions, the distal oesophagus and the oesophageal zone of the stomach. In formalin-fixed and paraffin-embedded tissues an immunoperoxidase technique was established to demonstrate deposits of the immunoglobulins G and M and the complement component C3 providing the opportunity to compare histological and immunohistological findings. Résumé— Un cheval hongre de 3 ans a été présenté avec une dermite chronique caractérisée par des érosions, des ulcères, des croutes, des squames et une alopécie très étendue. Le diagnostic de pemphigus foliacé reposait sur l'anamnèse, l'examen clinique et les résultats des examens histopathologiques et immunopathologiques. Les lésions histologiques typiques comprenaient des acantholyses intraépldermiques et la formation de fissures tant au niveau de lépiderme que des follicules pileux. En outre, des bulks et des érosions ont été retrouvées au niveau de différentes junctions cutanéomuqueuses et de la partie distalé de l'oesophage. Une technique d'immunopéroxydase sur tissus fixés au formol et en paraffine a été utilisée pour mettre en évidence des dépôts d'immunoglobulines G et M et de C3, permettant de comparer les observations histologiques et immunopathologiques. Zusammenfassung— Ein dreijähriger Wallach wurde mit einer generalisierten chronischen Dermatitis vorgestellt, die durch Erosionen, Ulzerationen, Krusten, Schuppen und ausgedehnte Alopezie gekennzeichnet war. Die Diagnose Pemphigus foliaceus stützte sich auf den Vorbericht, die klinischen Symptome, die histologischen Veränderungen und die Ergebnisse des immunohistologischen Tests. Die typischen histopathologischen Befunde umfaßten intraepidermale Akantholyse und Spaltbildung sowohl in der Epidermis wie im Epithel des Haarfollikels. Zusätzlich wurden Blasen und erosive Veränderungen in den Epithelien verschiedener mukokutaner übergänge, im distalen ösophagus und in der ösophagealen Zone des Magens gefunden. An formalinfixiertem und in Paraffin eingebettetem Gewebe wurde eine Immunoperoxidasetechnik durchgeführt, um die Ablagerungen von Immunglobulinen G und M und der Komplementkomponente C3 zu zeigen, wodurch die Gelegenheit bestand, histologische und immunohistologische Befunde zu vergleichen. Resumen Un caballo de tres anos fue presentado con una dermatitis crónica de tipo generalizado presentando erosiones, ulceraciones, costras y escamas epidérmicas, además de una alopecia generalizada. Una diagnosis de pémfigo foliáceo se basó en la historia y cuadro clínico, lesiones histológicas y resultados de tests inmunohistológicos. Los hallazgos dermato-histopatológicos típicos comprendieron acantolisis intraepidermica y la formación de indentaciones epidérmicas en ambos, epidermis y epitelio del folículo piloso. También se observó la presencia de vesículas y lesiones erosivas en el epitelio de las uniones mucocutaneas, asi como en áreas distales del esófago, y en zonas esofágicas del estómago. Después de la fijación en formol y sumersión en parafina de los tejidos, se utilizo la técnica de inmunoperoxidasa para la demonstratión de depósitos de inmunoglobulinas G y M, y el complemento C3, que proporcionó la oportunidad de comparar los hallazgos inmuno e histológicos.     

Electrochemotherapy for the Treatment of Multiple Melanomas in a Horse

A 22-year-old Camargue mare was referred for showing signs of discomfort during chewing, building up of food in the mouth, and foul odor from the mouth. On physical examination, the mare presented bilateral pigmented labial masses affecting the upper and lower lips, more in the form of plaques at the mucocutaneous junction as well as multiple perivulvar and perianal lumps. The skin lesions were biopsied for histopathologic examination and the clinical suspect of melanoma was confirmed. The owner elected the lesions to be treated with electrochemotherapy using the drug cisplatin. After two sessions, the nodules were shrunk by 50% and the horse’s ability to feed normally was restored: at that time, the owner had the treatment discontinued because of financial issues. The horse is still in partial remission after 1 year from the end of the treatment. Electrochemotherapy can be successfully used to palliate large melanomas in horses.     

Bilateral Catastrophic Metacarpal Fractures in a Quarter Horse Gelding

A 5 year-old, 450 kg, American Quarter Horse gelding was presented for postmortem examination. The horse had sustained multiple fractures of the metacarpal bones of both fore limbs while being ridden at a canter. Based on the radiographic presence of parasagittal fractures in the condyles of the distal third metacarpus, we theorized that the fractures in this horse likely originated in the metacarpophalangeal joint and propagated into the diaphysis resulting in catastrophic failure. The unique finding in this case is that these injuries occurred in a horse that was not being trained for racing. Owners and trainers should be aware that horses trained for disciplines other than racing can develop condylar fractures similar to racing Thoroughbreds and Quarter Horses.     

Prevalence of Brucellosis in Horse North-East of Iran

Brucella preferentially infects cattle, swine, sheep, and goats. However, some epidemiological surveys have been carried out to investigate nonruminants, such as horses. Horse brucellosis has been found in clinical cases, but there are few epidemiologic patterns. Between May 2008 and April 2009, a total of 120 horses were screened for brucella infections in Mashhad, Iran, by the rose bengal test and the tube agglutination test. Sera from three horses were found positive by rose bengal test and tube agglutination test, and therefore the prevalence rate was 2.5%. In horses, the highest individual seroprevalence was in an animal kept close under the intensive system, with other animals such as cattle, sheep, and goats. The zoonotic aspects of brucellosis from the horse must, therefore, be considered because the disease is important from a public health standpoint. The present study documents the first serological evidence of Brucella spp. infection in horses in Iran.     

Incidence of Insect Bite Hypersensitivity in a Small Population of Warmblood Horse Breed in the Czech Republic

Insect bite hypersensitivity (IBH) is a serious equine disease with a complex etiology, affecting many breeds. The availability of a small closed population with a relatively high incidence of IBH (28%) offered the chance to contribute to a better understanding of the etiology of IBH. All 736 Warmblood horses, kept in lowland floodplain meadows in the Czech Republic, were analyzed in the period 1998-2010. The morbidity rate in the offsprings of particular stallions was significantly different; the lowest was 10% and the highest 75%. The assumption that the highest occurrence of healthy offspring would be in healthy parents and vice versa was confirmed. The sex of the offsprings was not significant. To decline the disorder prevalence in this population, stud stallions should be IBH negative; afflicted mares can be tolerated to a certain extent, but their male offspring must never be used as stud. Heredity control is necessary, and stallions with IBH+ offspring should be culled. There is to date no reliable treatment available, and therefore, the development of preventive measures is particularly important. The incidence of IBH could be lowered by prudent breeding, and thus immunotherapy and complex herd management would not be necessary. However, this would be a long-term and complex process.     

Choroid plexus tumors in 56 dogs (1985-2007)

Background: Choroid plexus tumors (CPTs) comprise approximately 10% of all primary brain tumors in dogs. The clinical utility of magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, or both in the presumptive diagnosis of CPTs has not been determined.
Objectives: To report MRI and CSF findings in dogs with CPT and determine if there are distinguishing features that allow clinical discrimination between the tumor grades.
Animals: Fifty-six client-owned dogs with naturally occurring CPT.
Methods: Retrospective case series. The inclusion criterion was histologically confirmed CPT. Blinded review of cranial MRI and cisternal CSF analysis was performed.
Results: Thirty-six of 56 dogs had a choroid plexus carcinoma (CPC) and 20 had a choroid plexus papilloma (CPP). Golden Retrievers were overrepresented compared with the hospital population (frequency 3.7 times that expected, confidence interval 95%= 2.0–6.7, P < .0002). Median CSF protein concentration in CPCs (108 mg/dL, range 27–380 mg/dL) was significantly higher than in CPPs (34 mg/dL, range 32–80 mg/dL) ( P = .002). Only dogs with CPCs had a CSF protein concentration >80 mg/dL. Cytological evidence of malignancy in CSF was seen in 7 of 15 CPCs. Only CPCs had evidence of intraventricular or subarachnoid metastases on MRI.
Conclusions and Clinical Importance: MRI, CSF analysis or both can help to differentiate between CPPs and CPCs, and may provide valuable prognostic and pretreatment information.     

Successful Management of Severe Open Metacarpophalangeal Joint Dorsal Luxation in a Horse

A 3-year-old Darreh-Shuri stallion was presented with left forelimb open dorsal fetlock luxation immediately after being hit by a motorized vehicle. The horse was in a non–weight-bearing position on the affected limb. General physical examination revealed normal vital parameters and no special concurrent abnormality. Radiographic examination in lateromedial and dorsopalmar views of the affected limb showed complete luxation of the metacarpophalangeal joint with no fractures. Ultrasonographic evaluation revealed intact collateral ligaments. Under general anesthesia and following routine preparations, forceful manual pressure was exerted on the distal part of the metacarpus and proximal part of the first phalanx to reduce the luxation. Joint capsule and skin laceration were sutured. Intraarticular amikacin (500 mg) was administered and repeated on the third and fifth days postoperatively. A palmar polyvinyl chloride, synthetic plastic polymer (PVC) splint was placed following adequate padding from the carpus to the toe. The higher and lower third of the splint was casted and the middle part left open to manage the joint and skin lesion. Intraarticular sodium hyaluronate (20 mg) was administered 10 days later. After cast removal following 5 weeks, the stallion revealed no sign of lameness. The owner was instructed to keep the stallion confined to a stall for at least 2 more months with a restricted daily short hand walk. Special casting methods for immobilization of a limb with an open joint luxation can tremendously improve the healing process.     

Hyperthermia and Delayed-Onset Myopathy after Recovery from Anesthesia in a Horse

A 13-year old Thoroughbred cross gelding (528 kg) underwent lameness investigation. Because of his temperament, general anesthesia was required to facilitate ultrasound of the left fore fetlock and intra-articular medication of three joints. Anesthesia was induced with ketamine/diazepam after acepromazine/detomidine premedication. Anesthesia was maintained for 40 minutes with a guaifenesin/detomidine/ketamine intravenous infusion. Recovery from anesthesia was initially uneventful, although of a moderate duration (70 minutes). Once standing, the horse proceeded to box walk in an agitated state and became recumbent on two occasions. The horse was manually restrained, at which time its rectal temperature was 41.8°C. Cooling measures were employed (fans, ice-water enemas, wet rugs, intravenous fluid therapy (IVFT), and topical application of surgical spirit) until rectal temperature reached 38.7°C. IVFT was continued for a further 16 hours. Four days after recovery from anesthesia, bilateral triceps, deltoideus, trapezius, and rhomboideus muscle swelling was observed. Blood creatinine kinase was elevated (24,898 IU/L). Treatment for postanesthetic myopathy was initiated (hot packing of the muscle groups, topical dimethylsulfoxide [DMSO] cream application, and oral phenylbutazone). Myoglobinuria was not observed at any time. Muscle swelling decreased over the following 3 days. The horse was discharged on day 11 and has since returned to work.