ORIGINAL RESEARCH: Significance of surface epithelial cells in canine cerebrospinal fluid and relationship to central nervous system disease

Unique cytologic and imaging features of a lumbosacral oligodendroglioma in a cat

A 12-y-old castrated male domestic longhaired cat had progressive paraparesis and neurolocalization of L4-S3. MRI revealed a circumscribed intradural-extraparenchymal mass from L5 to S1 that was T2 and short tau inversion recovery hyperintense and strongly contrast-enhancing. Cytologic interpretation of a blind fine-needle aspirate obtained through the L5-L6 space was a tumor of probable mesenchymal origin. A pair of suspect neoplastic cells was seen on a cytocentrifuged preparation of the atlanto-occipital CSF sample, despite a normal nucleated cell count (0 × 106/L) and total protein (0.11 g/L) with only 3 RBCs × 106/L. Clinical signs progressed despite increasing doses of prednisolone and cytarabine arabinoside. Repeat MRI on day 162 demonstrated tumor progression from L4 to Cd2 vertebral segments with intraparenchymal extension. Surgical tumor debulking was attempted, but an L4-S1 dorsal laminectomy revealed diffusely abnormal neuroparenchyma. Intraoperative cryosection favored lymphoma, and the cat was euthanized intraoperatively 163 d following presentation. Postmortem examination was performed, and the final diagnosis was a high-grade oligodendroglioma. This case illustrates the cytologic, cryosection, and MRI features of a unique clinical presentation of oligodendroglioma.

Effects of stylet-in versus stylet-out collection of cerebrospinal fluid from the cisterna magna on contamination of samples, sample quality, and collection time

OBJECTIVE

To evaluate safety of stylet-in and stylet-out techniques for collection of CSF from the cisterna magna and to assess whether there were differences between techniques with regard to contamination of samples, sample quality, and efficiency of collection.

ANIMALS

10 adult purpose-bred research Beagles.

PROCEDURES

A prospective crossover study was conducted. Preanesthetic physical and neurologic examinations and hematologic analyses were performed. Dogs were anesthetized, and collection of CSF samples from the cisterna magna by use of a stylet-in or stylet-out technique was performed. Two weeks later, samples were collected with the other sample collection technique. Samples of CSF were processed within 1 hour after collection.

RESULTS

Cellular debris was detected in higher numbers in stylet-in samples, although this did not affect sample quality. The stylet-out technique was performed more rapidly. No adverse effects were detected for either technique.

CONCLUSIONS AND CLINICAL RELEVANCE

Both techniques could be safely performed in healthy anesthetized dogs. The stylet-out technique was performed more rapidly and yielded a sample with less cellular debris. Both techniques can be used in clinical practice to yield CSF samples with good diagnostic quality.

The distributional nexus of choroid plexus to cerebrospinal fluid, ependyma and brain: toxicologic/pathologic phenomena, periventricular destabilization, and lesion spread

Bordering the ventricular cerebrospinal fluid (CSF) are epithelial cells of choroid plexus (CP), ependyma and circumventricular organs (CVOs) that contain homeostatic transporters for mediating secretion/reabsorption. The distributional pathway ("nexus") of CP-CSF-ependyma-brain furnishes peptides, hormones, and micronutrients to periventricular regions. In disease/toxicity, this nexus becomes a conduit for infectious and xenobiotic agents. The sleeping sickness trypanosome (a protozoan) disrupts CP and downstream CSF-brain. Piperamide is anti-trypanosomic but distorts CP epithelial ultrastructure by engendering hydropic vacuoles; this reflects phospholipidosis and altered lysosomal metabolism. CP swelling by vacuolation may occlude CSF flow. Toxic drug tools delineate injuries to choroidal compartments: cyclophosphamide (vasculature), methylcellulose (interstitium), and piperazine (epithelium). Structurally perturbed CP allows solutes to penetrate the ventricles. There, CSF-borne pathogens and xenobiotics may permeate the ependyma to harm neurogenic stem cell niches. Amoscanate, an anti-helmintic, potently injures rodent ependyma. Ependymal/brain regions near CP are vulnerable to CSF-borne toxicants; this proximity factor links regional barrier breakdown to nearby periventricular pathology. Diverse diseases (e.g., African sleeping sickness, multiple sclerosis) take early root in choroidal, circumventricular, or perivascular loci. Toxicokinetics informs on pathogen, anti-parasitic agent, and auto-antibody distribution along the CSF nexus. CVOs are susceptible to plasma-borne toxicants/pathogens. Countering the physico-chemical and pathogenic insults to the homeostasis-mediating ventricle-bordering cells sustains brain health and fluid balance.