The utility of intraoperative impression smear cytology of intracranial granular cell tumors: Three cases.

Two adult male dogs (a 7-year-old shorthaired Chihuahua and 14-year-old Shih Tzu) and one adult female dog (a 9-year-old Maltese) presented for evaluation of new-onset seizure activity. Magnetic resonance imaging of the brain demonstrated a large, poorly marginated T2-weighted hyperintense, and strong contrast enhancing extra-axial mass in each case. A surgical biopsy for histopathologic evaluation was elected in all cases, and intraoperative impression smears were successfully obtained. Intraoperative cytology identified a homogenous population of round to polygonal cells with central to eccentric nuclei, coarse chromatin, and variably amphophilic to eosinophilic granular cytoplasm. Cytologic findings led to a suspected diagnosis of granular cell tumor (GCT) in all cases. Histopathologic review identified a densely cellular, unencapsulated neoplastic mass comprised of sheets of large round to polygonal cells with abundant eosinophilic cytoplasm containing numerous eosinophilic intracytoplasmic granules, confirming the diagnosis of GCT in all cases. The cases reported here are unique in that they reveal an accurate intraoperative cytologic diagnosis of a rare canine central nervous system neoplasm. Intraoperative cytology of the intracranial masses could provide clinicians with important and quick diagnostic and prognostic information; therefore, expediting decisions made intraoperatively. Further research is warranted to determine the diagnostic accuracy of intraoperative cytology for neoplasia in veterinary patients.

MANAGEMENT OF A REEVE'S MUNTJAC ( MUNTIACUS REEVESI) WITH SEIZURES USING LEVETIRACETAM.

This report describes the diagnosis and management of idiopathic epilepsy in a 4-yr-old intact female Reeve's muntjac ( Muntiacus reevesi). The patient was initially witnessed to have isolated paroxysmal events consistent with epileptic seizures (altered consciousness, lateral recumbency, tonic/clonic movement of limbs) lasting less than 3 min with an immediate return to normal consciousness. The seizure frequency increased to >3 seizures within 24 hr and phenobarbital 3 mg/kg orally every 12 hr was started. Because of continued epileptic seizures and low serum phenobarbital levels, the dose was increased until significant elevations of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were detected. Levetiracetam 40 mg/kg orally every 12 hr was initiated and the phenobarbital was weaned and discontinued. One breakthrough seizure has been witnessed in the 10 mo since starting levetiracetam.

Imaging diagnosis-MRI characteristics of a fourth ventricular cholesterol granuloma in a dog.

A 2-year-old male American Bulldog experienced paroxysmal staggering, altered consciousness, and hyperesthesia. Magnetic resonance (MR) imaging enabled recognition of a fourth ventricular mass causing compression of the cerebellum and brainstem and obstructive hydrocephalus. The mass was uniformly T2-hyperintense and predominantly T1-hypointense. A fluid line was evident on the fluid-attenuated inversion recovery images. A thin rim of contrast enhancement was noted. Histopathologic diagnosis was a cholesterol granuloma. We were unable to identify any other reports of a cholesterol granuloma residing in the fourth ventricle of a dog. This case report documents the clinical, diagnostic imaging, and histopathologic findings of a canine intracranial cholesterol granuloma. © 2012 Veterinary Radiology & Ultrasound.