Intracranial schwannoma in a cow

A nine year old Hereford crossbred cow with a history of progressive neurological signs was referred to the Western College of Veterinary Medicine, Saskatoon. A large intracranial mass, histologically identified as a schwannoma, was found to be compressing the left brain stem and appeared to have arisen from the left fifth cranial nerve.     

Intracranial botryomycosis in a mature horse

This case report describes an unusual diagnosis of central nervous system botryomycosis in a horse. A 16‐year‐old Welsh Section D gelding was evaluated for acute onset of hypermetric ataxia, leaning to the left and head tilt to the right. Based on the neurological signs, a cerebellar lesion with accompanying vestibular disease was suspected and supportive therapy consisting of antimicrobial and glucocorticosteroid drugs and hypertonic saline was instituted. This resulted in marked clinical improvement over a 48 h period. Computed tomography performed in the standing, sedated horse following initial stabilisation identified extensive sclerosis and lysis of the right temporal and occipital bones, consistent with an infectious or neoplastic process. Based on the grave prognosis for survival despite the clinical improvement, euthanasia was undertaken. Post mortem magnetic resonance imaging identified a mass lesion impinging on the right cerebellar hemisphere, sclerosis of the temporal and occipital bones lateral and ventral to the mass, as well as destruction of the temporal bone between the inner ear and the cerebellum. These changes corresponded to the presence of a mass within the right dorsal temporal bone, extending into the right lateral temporal bone. The mass extended to compress and adhere to the right lateral hemisphere of the cerebellum. A histopathological diagnosis of botryomycosis was made, affecting the temporal and occipital bones and compressing the cerebellum.     

Intracranial trauma associated with extraction of a temporal ear tooth (dentigerous cyst) in a horse

Heterotopic polyodontia is typically associated with a sinus and a fistulous tract with a secreting membrane which extends to an ectopic tooth attached to the temporal bone. Recommendations for treatment include complete excision of the tract, the dental component, and the lining of the alveolar socket. Iatrogenic cerebral trauma was encountered during surgical extraction of an ectopic tooth. At post-mortem examination a second ectopic tooth was found compressing the right side of the cerebellum.     

Intracranial medulloblastoma as the cause of progressive ataxia in a 6-month-old draft horse cross gelding

We describe the unique clinical presentation of a central nervous system neoplasm in a 6-month-old draft horse cross gelding. Based on the neurologic examination at admission, neurolocalization was most consistent with a mildly asymmetric cervical, multifocal, or diffuse myelopathy. Mild vestibular involvement also was considered, but no cranial nerve deficits were observed. The gelding was negative for Sarcocystis neurona or Neospora hughesi based on paired serum and cerebrospinal fluid (CSF) samples analyzed, with no evidence of cervical compression based on contrast myelography. The horse was euthanized because of progression of clinical signs. At necropsy, a mass was identified associated with the cerebellum, and histopathology was consistent with medulloblastoma, which has not been reported previously in the horse.     

Giardiasis in a horse

Giardia infection was believed responsible for chronic diarrhea, weight loss, lethargy, inappetence, and dermatitis in a 4-year-old Thoroughbred horse. Fecal cysts were detected by the zinc sulfate centrifugal flotation method. All clinical signs resolved upon treatment with metronidazole suspension (5 mg/kg body weight per os, TID for 10 days).     

Choledocholithiasis in a horse

Choledocholithiasis was diagnosed in a five-year-old gelding on the basis of laboratory results and histopathology. Surgery was performed to relieve the obstruction. The horse responded favorably and at 39 days postoperatively was clinically and clinicopathologically normal.     

Chromomycosis in a horse

A 6-year-old Quarter Horse gelding was examined because it had a sharply circumscribed, firm, brown-black, roughly spherical dermal nodule at the right tuber ischii. After it was excised, the lesion did not recur. Microscopically, the dermis of the excised specimen had multiple pyogranulomas, many of which contained thick-walled, dark brown fungal elements, some with internal septation compatible with chromomycotic fungi. Chromomycosis is a rare skin disease in the horse. It may be included in the differential diagnoses of nodular and/or pigmented skin lesions that include melanoma, pyogranuloma, mycetoma, squamous cell carcinoma, habronemiasis, and onchocerciasis.