•Before lumbar puncture, the risk of herniation through the foramen magnum, especially in the posterior fossa tumors, has to be considered. A CT or MRI of head can examine ventricular size as an indicator of noncommunicating, hydrocephalus

•Xanthochromic cerebral fluid, high protein level, and a high tendency to coagulate indicate tumor spread

9.8.2Electroencephalography

• For examination of unclear focal neurological abnormalities

9.8.3Stereotactic Biopsy

•In inoperable tumors, this type of biopsy can provide a pathological diagnosis and help determine the optimal therapeutic approach (radioand/or chemotherapy)

9.9Differential Diagnosis

•Brain abscess (fever, cardiac murmur in congenital cyanotic heart disease)

•Subdural hematoma: anemia, retinal hemorrhage

•Hydrocephalus: headache, vomiting, subarachnoid hemorrhage, Guillain–Barré syndrome

•Tuberculoma: exposure to tuberculosis

•Pseudotumor cerebri: after otitis media, hormonal abnormalities

•Encephalitis: meningism, fever, seizure, stupor

9.10Metastatic Spread

•Observed in medulloblastoma, pinealoma, germinoma, ependymoma

•Bone metastases occasionally in medulloblastoma

•Metastatic spread via ventriculoperitoneal shunt, via cerebral spinal fluid: mostly in ependymoma with subarachnoid metastases, in medulloblastoma, with drop metastases causing paraplegia

•In germinoma, metastases also outside CNS

•Secondary brain metastases:

–Leukemia with intracerebral pressure, hydrocephalus

–Non-Hodgkin lymphoma with focal neurological symptomatology

–Langerhans cell histiocytosis, rhabdomyosarcoma, nephroblastoma, Ewing sarcoma, neuroblastoma, melanoma