The nucleated cells seen in normal adult CSF are predominantly lymphocytes and monocytes/macrophages. A rare neutrophil may be seen. An increased number of lymphocytes, monocytes, or neutrophils in CSF is termed pleocytosis. Morphologically normal cells can be seen in abnormal numbers in meningitis and inflammation.
The monocyte/macrophage appears when clean-up of the CSF is necessary because of degenerating cells and debris, often due to a subarachnoid hemorrhage (SAH) or meningitis.
Cells that may be seen in cerebrospinal fluid can be divided into four categories:
- Mature peripheral blood cells
- Immature hematopoietic cells
- Tissue cells
- Malignant cells
Table 8 lists these types and their significance.
Tissue cells are often seen in spinal fluid samples. It is important to recognize these cells so that they are differentiated from tumor and blast cells. Pathologists must review any slides with presumptive malignant cells, unidentified cells, or immature stages of cells, such as blasts. Since criteria for review may vary from one laboratory to another, be sure to check the requirements in your laboratory before reporting the differential.
Table 8. Nucleated Cells That May Be Present in CSF.| Cell Type | Appearance of Cell in CSF | Significance |
Lymphocytes
|  | Low number is normal.
Increased in: - Viral meningitis
- Tubercular meningitis
- Fungal meningitis
- Syphilitic meningitis
- Multiple sclerosis
- Drug abuse
- Lymphoma
- Leukemia
- Guillain-Barré syndrome
- Chronic alcoholism
- Polyneuritis
|
Monocytes/Macrophages
|  | Low number is normal.
Increased in: - Previous subarachnoid hemorrhage
- Response to foreign material in the CSF
- Meningitis
- Inflammation
- Tumors
|
| Neutrophils |  | Low number is normal following cytocentrifugation.
Increased in: - Prominent pleocytosis in bacterial meningitis
- Early tuberculosis and fungal infections
- Hemorrhage
- Cerebral abscess
- Tumors
|
Eosinophils
|  | Increased in response to foreign CSF material including: - Allergic reaction
- Parasites
- Fungal meningitis
- Leukemia
- CSF contamination with blood
|
| Choroidal and Ependymal cells |  | - Cells of the epithelial lining of the CNS; not clinically significant.
- May be seen in CSF following neurosurgical procedures.
- Often seen in clumps with no nuclear or cytoplasmic irregularities.
|
| Malignant cells |  | |
| Blast cells |  | |
