Chapter 28 - Mass lesions - Neoplasm

Questions

Define the following terms:

metastasis, primary brain tumor, meningioma, glioma, oligodendroglioma, astrocytoma, anaplastic astrocytoma, glioblastoma multiforme, medulloblastoma, ependymoma, drop metastasis, sensory level, myelopathy, radiculopathy, non-metastatic complications of cancer, paraneoplastic syndrome.
Metastasis is the spread of a malignant tumor to a remote part of the body.
A primary brain tumor is a tumor that develops from normal tisses of the brain.
A meningioma is a (usually benign) tumor that develops from coverings of the brian.
A glioma is a tumor that develops from glial cells.
An oligodendroglioma is a glial tumor that develops from glial cells.
An astrocytoma is a glial tumor that develops from astrocytes.
An anaplastic astrocytoma is a high grade glial tumor that develops from astrocytes.
A glioblastoma multiforme is a malignant glial tumor that develops from astrocytes.
A medulloblastoma is a tumor that develops from primative neuroectodermal cells (usually in children).
An ependymoma is a glial tumor that develops from ependymal cells.
A drop metastasis is a metastasis, usually from glioblatomas or ependymomas, that occurs through the cerebrospinal system. it typically occurs around the lumbar nerve roots or the lower spinal cord.
A sensory level is a line on the trunk below which sensation is lost.
A myelopathy is damage to the spinal cord.
A radiculopathy is damage to a nerve root.
Non-metastatic complications of cancer are those that don't result from direct involvement by the tumor.
A paraneoplastic syndrome is a syndrome, usually from development of an autoimmune reaction, where there is damage to neural structures.


28-1. How are tumors localized?

Answer 28-1. Tumors are localized by their focal effects on the brain.

28-2. What are the signs that localize tumors?

Answer 28-2. There are several signs that localize tumors:

Cortical signs - aphasia, hemiparesis, hemianopsia/quadrantanopsia, sensory loss, parietal lobe symptoms (neglect, agnosia), frontal lobe signs (dysinhibition, apathy personality change)

Cerebellar - incoordination, ataxia

Lateral brain stem - unilateral loss of pin and temperature sense on face

Brain stem - cranial nerve palsy

Loss of upgaze - dorsal brain stem, pineal region

Bitemporal hemianopsia - pituitary region

Spinal cord - saddle anesthesia, paraplegia, sphincter dysfunction

28-3. What are some irritative signs of tumors of the nervous system?

Answer 28-3. Radiculopathy is due to irritation of the nerve roots. A significant percentage of brain tumors present with seizure when they irritate the cerebral cortex.

28-4. What are the signs and symptoms of increased intracranial pressure that can be found in brain tumors?

Answer 28-4. The patient with increased intracranial pressure may be awakened from sleep by headache. Papilledema or loss of venous pulsations in fundus of eye may be observed. Cushing response (increase BP with decrease pulse) occurs in a small number of cases. There may be signs of herniation (there are several types: subfalcine/cingulate, transtentorial, cerebellar). Transtentorial herniation is most common, often resulting in a dilating pupil (usually ipsilateral) and hemiparesis (usually contralateral).

28-5. What signs and symptoms are common in tumors of the pituitary region?

Answer 28-5. Endocrine problems or bitemporal hemianopsia are common with tumors of the pituitary region.

28-6. What signs and symptoms are common in tumors of the pineal region?

Answer 28-6. Failure of upgaze (Parenaud's syndrome) may be seen with pineal/tectal region neoplasms.

28-7. Why do symptoms of brain tumors often respond to steroids?

Answer 28-7. Brain tumors, especially metastatic ones, often result in severe vasogenic edema. This type of tumor often responds to steroids with some inprovement in symptoms.

28-8. What are the types of primary brain tumors?

Answer 28-8. Most primary brain tumors are named according to their cell of origin: glioma, ependymoma, meningioma, lymphoma (either primary or spread from elsewhere), Schwanoma, pituitary adenoma, primitive neuroectodermal tumor and pinealoma. The gliomas may be subdivided into astrocytomas (4 grades, with glioblastoma multiforme being the worst) and oligodendrogliomas.

28-9. Why is it usually impossible to cure a glioma?

Answer 28-9. Gliomas often infiltrate the brain so complete resection is impossible.

28-10. What glioma is usually resectible?

Answer 28-10. Cerebellar astrocytoma (pilocytic astrocytoma) in children are usually benign and resectable if found early.

28-11. What tumors are primarily localized to the posterior fossa?

Answer 28-11. Meningioma, ependymoma, acoustic neuroma (Schwanoma), cerebellar hemangioblastoma are usually localized to the posterior fossa. Many childhood brain tumors (ependymoma, astrocytoma, medulloblastoma) are localized to the posterior fossa. The prognosis is highly variable: cerebellar astrocytoma has a good prognosis, pontine glioma has a bad prognosis because of location. Medulloblastoma also has a bad prognosis while the prognosis of ependymoma depends on location and the presence/absence of drop metastasis elsewhere in the subarachnoid space.

28-12. What are the treatments for brain tumors?

Answer 28-12. Surgical resection is possible for benign tumors like meningioma and sometimes for solitary metastasis (if the systemic cancer controllable). Chemotherapy is limited by the blood-brain barrier and only specific types can be used. Sometimes chemotherapeutic agents can be delivered to the intrathecal space. Radiation is often useful for treatment, but it can damage the brain, especially long-term. For example it may result in necrosis that looks like recurrent tumor. There are experimental approaches to block angiogenesis or immune targeting.

28-13. What are non-metastatic complications to systemic cancers?

Answer 28-13. Patients with systemic cancer may develop neurologic symptoms of several types even if the cancer does not metastasize to the brain, and the symptoms can be related to a stroke, an infection, side effects of treatment , paraneoplastic syndrome. There are several paraneoplastic syndromes due to autoantibodies. These can produce: a subacute cerebellar syndrome; polyneuropathy; myoneural junction disease (weakenss); or confusional state.

28-14. What is the most common cause of tumors of the spine?

Answer 28-14. Most tumors of the spine are metastatic.

28-15. What are the common signs and symptoms of metastatic tumors of the spine?

Answer 28-15. Metastatic tumor of the spine often result first in back pain (that may persist even at rest), with subsequent signs of acute or subacute myelopathy (initially flaccid weakness, upgoing toes, sensory level over the trunk, bladder and bowel dysfunction), possible radiculopathy at the level of the tumor. The level of back pain and the radiculopathy are the most predictive of the location of the tumor.

28-16. Why is it critical to identify malignant spinal cord compression early?

Answer 28-16. It is critical to identify malignant spinal cord compression early because the outcome of treatment depends on the severity of deficit at the beginning of therapy.

28-17. What is the standard therapy for spinal cord metastatic disease?

Answer 28-17. High-dose steroids are often helpful along with radiation therapy are the common initial measures. These may be used with or without surgery (usually depending on the stability of the spine).

28-18. What are the primary tumors of the spine?

Answer 28-18. There are rare primary tumors of nerve root (neurofibromas, Schwanomas), meningiomas, gliomas. Also, there are rare tumors inside the spinal cord, mainly ependymoma and glioma.

28-19. How can you evaluate possible metastatic disease affecting the nervous system?

Answer 28-19. MRI scans are much better than CT scans at detecting metastasis (especially small ones), and CT scans are not very effective (particularly in the spine and posterior fossa of the head) unless there is destruction of bone. Plain x-rays are useful when the metastasis involves bone. At the present time, tissue diagnosis is critical to determine the type of tumor. In the future MR spectroscopy holds promise for noninvasive diagnosis.