Ch. 6 - Cerebrospinal Fluid Flashcards
What is the total CSF volume, and how much is produced each day?
150mL, with 500mL produced per day (cycled approximately 4x)
How can CSF be obtained?
Through lumbar puncture (usually L4, rarely at cisterna magna) or through Ommaya reservoir collection.
How do bloody taps obscure diagnosis?
They reduce the significance of neutrophils, eosinophils, or leukemic blasts which may be passengers in the blood.
Under what conditions will malignant tumors be identifiable on CSF?
If parenchymal, they must disrupt the ependymal lining to communicate with the ventricles.
If metastatic, they must seed the leptomeninges.
How are the sensitivity and specificity of CSF cytology?
Low sensitivity, high specificity.
What are the normal elements of CSF cytology?
Often sparse to no cells. Maybe some lymphocytes and monocytes.
Describe the cytology of ependymal cells.
Round nuclei with moderate cytoplasm, often cohesive.
Describe the cytology of brain matter.
Fibrillary texture containing glial cells, neurons, and maybe some capillaries.
How can germinal matrix cells be recognized in neonatal CSF?
(mimics high-grade tumors such as medulloblastoma)
Look for associated siderophages.
What are the significance of plasma cells in CSF? Eosinophils?
Plasma cells: Associated with syphilis, MS, neurocysticercosis, lyme disease and TB.
Eosinophils: Parasites (especially tapeworm larvae), coccidoides, VP shunts, hematologic malignancies, drug reactions…
In which infectious meningitides should you expect to see the offending organism?
Cryptococcus
Describe the morphology of cryptococcus.
5-15um round yeast forms with thick mucinous refractile capsule.
Describe the cytology of aseptic meningitis.
Increase in lymphocytes (some irregular) and monocytes.
What is Mollaret meningitis?
An idiopathic recurring aseptic meningitis thought to be due to HSV, that resolves spontaneously. Characterized by “Mollaret monocytes” with footprint-like clefted nuclei.
What is angiostrongyliasis?
“Rat lungworm”, a parasitic infection with frequent CNS involvement by larvae…that is often self-limited?
Describe the morphology of Naegleria Fowleri.
Large nucleus, little cytoplasm. Distinctive motility on wet preparations.
What cancers have proclivity towards CSF involvement? What is the most common occult site.
Small cell, melanoma; also breast, lymphomas/leukemias.
Lung is the most common occult site.
Describe the cytologies of metastatic lung carcinomas.
Adenocarcinoma: Most common; isolated or small clusters of cells with eccentric nuclei and abundant cytoplasm.
SQC: Rare, cohesive, maybe keratinizing.
SCLC: Small molding apoptotic and necrotic.
Describe the cytology of IDC and ILC in the CSF.
IDC: Linear rows or rings. Large with round nucleus and prominent nucleolus and scant cytoplasm.
ILC: Medium-sized isolated cells often with signet ring morphology.
Describe the cytology of melanoma metastatic to CSF. Can it be primary in the CNS?
Large cells with macronucleolus, sometimes melanin and associated melanophages.
Yes, in melanosis cerebri there are melanocytes in the leptomeninges.
How common is CNS involvement in ALL?
5% of cases–the most common CSF-involving disease in children and among hematologic malignancies overall.
What lymphomas have a high affinity for the CNS?
DLBCL, LBL, Burkitt
Describe the cytology of primary CNS lymphoma.
Often DLBCL-like. Diagnosis is difficult because of obscuring reactive T-cells, so rely on flow.
Describe the cytology of medulloblastoma.
Small to medium-sized cells with hyperchromatic nucleus, scant cytoplasm, nuclear molding and sometimes nucleoli. Looks like any other SRBCT…
Describe the cytology of astrocytomas.
Look for large pleomorphic cells with coarse chromatin, irregular nuclear outlines, and cytoplasmic extensions.
Describe the cytology of ependymoma.
Isolated or small groups of cells with rouund, eccentric nuclei. Hard to distinguish from benign ependymal cells, though there are anaplastic cases.
Describe the cytology of oligodendroglioma.
As you’d expect; uniform polygonal cells with round nuclei and pronounced perinuclear cytoplasmic clearing.
Describe the cytology of AT/RT.
Rhabdoid cells, binucleation with inclusion-like structure pushing aside the nucleus.
Describe the cytology of choroid plexus tumors.
Varies from simple papilloma (large cluster, uniform cuboidal cells with round nuclei) to carcinoma with pronounced atypia.
Describe the cytology of germinoma.
Isolated cells with large round nucleus with prominent nucleolus and moderate cytoplasm (same as seminoma).
