BRAIN TUMORS
A brain tumor is a localized intracranial lesion that occupies
space within the skull. Primary brain tumors originate from
cells and structures within the brain. Secondary, or metastatic,
brain tumors develop from structures outside the brain (lung,
breast, lower gastrointestinal tract, pancreas, kidney, and skin
(melanomas)) and occur in 10% to 20% of all cancer patients.
Brain tumors rarely metastasize outside the central nervous
system but cause death by impairing vital functions(respiration)
or by increasing intracranial pressure (ICP).
Classifications
Brain tumors are classified as follows:
• dural meningiomas-those arising from the covering of the
brain.
• acoustic neuromas-those developing in or on the cranial
nerves.
• various gliomas-those originating in the brain tissue.
• metastatic lesions- originating elsewhere in the body.
• Tumors of the pineal gland, pituitary, and cerebral blood
vessels are also included in the types of brain tumors.
Tumors may be benign or malignant. A benign tumor may
occur in a vital area and have effects as serious as a malignant
tumor.
Types of Tumors
• Meningiomas are common benign encapsulated tumors of
, arachnoid cells on the meninges. They are slow-growing
and occur most often in middle-aged women.
• An acoustic neuroma is a tumor of the eighth cranial nerve
(hearing and balance). It may grow slowly and attain
considerable size before it is correctly diagnosed.
• Gliomas -the most common brain neoplasms, cannot be
totally removed without causing damage, because they
spread by infiltrating into the surrounding neural tissue.
• Pituitary adenomas may cause symptoms as a result of
mass effects (pressure) on adjacent structures (eg, optic
nerve or third ventricle) or hormonal changes (eg,
galactorrhea or Cushing' disease).
• Angiomas are masses composed largely of abnormal blood
vessels and are found in or on the surface of the brain;
they may never cause symptoms, or they may give rise to
symptoms of brain tumor. The walls of the blood vessels in
angiomas are thin, increasing the risk for cerebral vascular
accident (stroke).
Clinical Manifestations
Generalized (Increasing ICP) Symptoms
• Headache, although not always present, is most common
in the early morning and is made worse by coughing,
straining, or sudden movement. Headaches are usually
described as deep, expanding, or dull but unrelenting.
Frontal tumors produce a bilateral frontal headache
;pituitary gland tumors produce bitemporal pain; in
cerebellar tumors, the headache may be located in the
suboccipital region at the back of the head.
A brain tumor is a localized intracranial lesion that occupies
space within the skull. Primary brain tumors originate from
cells and structures within the brain. Secondary, or metastatic,
brain tumors develop from structures outside the brain (lung,
breast, lower gastrointestinal tract, pancreas, kidney, and skin
(melanomas)) and occur in 10% to 20% of all cancer patients.
Brain tumors rarely metastasize outside the central nervous
system but cause death by impairing vital functions(respiration)
or by increasing intracranial pressure (ICP).
Classifications
Brain tumors are classified as follows:
• dural meningiomas-those arising from the covering of the
brain.
• acoustic neuromas-those developing in or on the cranial
nerves.
• various gliomas-those originating in the brain tissue.
• metastatic lesions- originating elsewhere in the body.
• Tumors of the pineal gland, pituitary, and cerebral blood
vessels are also included in the types of brain tumors.
Tumors may be benign or malignant. A benign tumor may
occur in a vital area and have effects as serious as a malignant
tumor.
Types of Tumors
• Meningiomas are common benign encapsulated tumors of
, arachnoid cells on the meninges. They are slow-growing
and occur most often in middle-aged women.
• An acoustic neuroma is a tumor of the eighth cranial nerve
(hearing and balance). It may grow slowly and attain
considerable size before it is correctly diagnosed.
• Gliomas -the most common brain neoplasms, cannot be
totally removed without causing damage, because they
spread by infiltrating into the surrounding neural tissue.
• Pituitary adenomas may cause symptoms as a result of
mass effects (pressure) on adjacent structures (eg, optic
nerve or third ventricle) or hormonal changes (eg,
galactorrhea or Cushing' disease).
• Angiomas are masses composed largely of abnormal blood
vessels and are found in or on the surface of the brain;
they may never cause symptoms, or they may give rise to
symptoms of brain tumor. The walls of the blood vessels in
angiomas are thin, increasing the risk for cerebral vascular
accident (stroke).
Clinical Manifestations
Generalized (Increasing ICP) Symptoms
• Headache, although not always present, is most common
in the early morning and is made worse by coughing,
straining, or sudden movement. Headaches are usually
described as deep, expanding, or dull but unrelenting.
Frontal tumors produce a bilateral frontal headache
;pituitary gland tumors produce bitemporal pain; in
cerebellar tumors, the headache may be located in the
suboccipital region at the back of the head.
