What Are Temporal Lobe Tumors?

The incidence of temporal lobe tumors ranks second among tumors in the cerebral hemisphere, second only to the incidence of frontal lobe tumors. The most common tumor is glioma, and metastatic tumors often occur at this site. More common in adults. The temporal lobe function is very complicated, and the function of some parts is not completely clear. Temporal lobe tumors often have no typical clinical symptoms in the early stages. In particular, those with tumors on the right side mostly show symptoms of increased intracranial pressure, and other symptoms and signs rarely appear. Therefore, they have been clinically called "quiet zone" or "dumb zone".

Basic Information

English name

temporal tumour

Visiting department

Neurology

Multiple groups

Adults

Common locations

brain

Common symptoms

Changes in vision, sensory aphasia, seizures, mental disorders, etc.

Clinical manifestations of temporal lobe tumors

Vision change

Visual field changes are often one of the early symptoms of temporal lobe tumors, and they have localization significance. When the tumor is located deep in the temporal lobe, the visual field defect in the upper quadrant of the contralateral isotropy may appear at the beginning of the disease due to affecting or destroying the optic bundle or optic radiation. As the tumor continues to grow, quadrant defects can develop into isotropic hemianopia. This hemianopia may be complete or incomplete and bilaterally symmetrical or asymmetric. For example, in a tumor in the posterior temporal lobe, hemianopia is mostly symmetrical .

2. sensory aphasia

Sensory aphasia can occur when tumors located in the dominant hemisphere damage the superior temporal gyrus in areas 41 and 42. Naming aphasia can occur when the posterior temporal lobe is damaged. This is one of the most reliable symptoms of a temporal lobe tumor. Such patients have lost the ability to understand other people's language and the ability to name objects, but preserve their ability to speak. Despite this, they often use typos, utter wrong words, and even have babbling. In severe cases, the patient's conversation cannot be understood at all, and at the same time the patient cannot understand the language of others. In addition, the development of temporal lobe tumors to the occipital occipital is often accompanied by dyslexia, dyslexia, inability to calculate, and visual ignorance.

3. Seizures

The incidence of seizures caused by temporal lobe tumors is second only to frontal lobe tumors. Some patients may also have localized seizures. Temporal lobe seizures are characterized by various threats, complex symptoms, and may include delirium, speech disturbance, psychomotor excitement, mood and disorientation, hallucinations, illusions, and memory impairment. Some patients show visual hallucinations such as deformed vision (hyperopia) and enlarged vision (macrovision). The auditory cortical representative area is in the temporal transverse gyrus. When the patient is phantom, he can hear the sound becomes larger or smaller, clocks, songs, drums, noise, etc. Auditory hallucinations are often accompanied by vestibular corona vertigo and paroxysmal tinnitus. The taste representative area is at the lower part of the central anterior gyrus. Damage to this part rarely causes taste disturbances, but hallucinations may occur when stimulated.

Automatism is also a common and representative symptom of temporal lobe epilepsy. It is an episodic and unconscious activity. Among them, mental exciters such as wounding, destruction, self-injury, and nakedness are more common. Patients often show unintended actions such as chewing, pouting, sucking, twisting of head and eyes. Deep temporal lobe tumors may have paroxysmal behavioral abnormalities, often accompanied by dreams, and patients have dreams, as if they are strange in dreams, often concurrent with hallucinations, as if returning to childhood, or panic.

4. Mental symptoms

Temporal lobe tumor mental disorders are also common symptoms, second only to frontal lobe tumors. The main symptoms are personality changes, emotional abnormalities, eccentricities, memory disorders, and indifferent expressions. Psychiatric symptoms occur more frequently and rapidly growing tumors in the dominant hemisphere temporal lobe.

5. cone sign

Tumors in the upper temporal lobe can compress the lower part of the frontal lobe and parietal lobe, causing motor or sensory disturbances in the face and upper limbs. Compressing the contralateral cerebral feet and inner capsule can cause pyramidal tract signs on the same side of the tumor, resulting in varying degrees. Of hemiplegia.

6. Other symptoms

Tumors on the medial temporal lobe can oppress the midbrain and cause oculomotor nerve palsy. Horner syndrome can occur when a temporal lobe tumor compresses the carotid sympathetic plexus. Basal ganglia involved contralateral limb tremor, chorea, hand and foot asthma, paralytic tremor syndrome. Spontaneous visceral pain may occur when island leaves are violated.

Temporal lobe tumor examination

Plain skull

There may be manifestations of increased intracranial pressure and tumor calcification, which appear in the corresponding parts of the temporal lobe tumor; local destruction and hyperplasia of the skull are also often consistent with the location of the tumor. The examination of the above plain radiographs is often reliable evidence for the diagnosis of temporal lobe tumors.

Ventricle angiography

Ventricular angiography for temporal lobe tumors is mainly to determine the location of the tumor. Its performance characteristics are as follows:

(1) Anterior and posterior images The lateral ventricle is shifted to the healthy side. The transparent septum and the third ventricle move in an arc shape to the opposite side. The outer corners above the anterior corners are pointed and point outward or upward. The lateral wall of the lateral cerebral ventricle is depressed and the transverse diameter becomes smaller.

(2) Lateral image On the lateral image and the anterior and posterior image, the lower angle changes significantly. If the tumor is located above the lower corner, the lower corner is displaced, and the displacement can be all or part; below the lower corner, the lower corner is moved upward; the tumor is located on the outside, the lower corner is moved inward; When the lower corner is shifted up, the distance between the lower corner and the body becomes smaller.

3. Cerebral angiography, carotid angiography of temporal lobe tumors

Location of tumors is mainly based on vascular displacement.

4. EEG

In the EEG examination of temporal lobe tumors, the localized rate of waves is very high, about 90%, and the frequency of waves is slow (0.5-2 times / second) and persistent. The background alpha wave is abnormal.

(1) Anterior temporal tumor polymorphic delta waves are relatively limited to the anterior temporal lead. The background alpha wave is generally unaffected. Spike detection rate is high.

(2) Post - temporal tumors Polymorphic delta waves mainly appear in the posterior and anterior temporal regions and can reach the lower parietal, apical, and occipital regions. There are weakened fast waves and waves around the tumor. The alpha wave on the diseased side often has changes in rhythm, slower frequency, lower or disappeared amplitude, and these characteristics can be used to distinguish from pretemporal tumors.

(3) Tumors of the temporomandibular occipital region Obvious waves can appear in the posterior temporal, subparietal , parietal, and occipital regions, but generally the lower parietal region is dominant. The alpha waves on both sides, especially the diseased side, have obvious disturbances and are interspersed with scattered delta waves and theta waves.

5. Brain Ultrasound

Ultrasound examination of temporal lobe tumors has the highest localization rate. Except for the tumor wave, the midline wave shifted most obviously to the contralateral side. When the ventricle is enlarged or hydrocephalus, the amplitude of the lateral ventricular wave increases, and the distance between the lateral ventricular wave and the midline wave increases.

6. Isotope brain scan

Temporal lobe tumor isotope scans have different manifestations depending on the nature, location, size, and vessel of the tumor, and the temporal lobe tumor scan has a higher positive rate.

7. Brain CT and MRI

CT diagnosis of temporal lobe tumors is mainly based on the changes in the density of the tumor tissue and the compression and displacement of the ventricle system by the tumor. Some tumors show high density and clear CT images; some tumors are clear due to calcification; some tumors are displayed as uniform or uneven low-density areas due to necrosis of tumor tissue or changes in edema around the lesion. Temporal lobe tumors are mostly gliomas and meningiomas. CT scans show high-density areas. A few tumors have calcifications, and cystic changes, necrosis, and edema show different density changes. The lateral ventricle and the third ventricle are often compressed, deformed, and displaced. MRI is known for its transverse, sagittal, three-dimensional, multi-angle and multi-parameter comparisons such as T ₁ , T ₂ , diffusion weighting, and enhancement. It is important for the qualitative and local diagnosis of temporal lobe tumors.

Diagnosis of temporal lobe tumors

Temporal lobe tumors are located in a "dumb zone". Early symptoms and signs are not obvious, and often require influential examinations to detect them. Although the advanced symptoms have certain specificity, the qualitative and scope of the tumor and the formulation of the surgical plan are inseparable from detailed imaging studies.

Differential diagnosis of temporal lobe tumors

Temporal lobe abscess

The clinical manifestations of temporal lobe abscesses, especially chronic temporal lobe abscesses, are similar to those of temporal lobe tumors, and sometimes difficult to distinguish. However, the clinical symptoms of brain abscesses, especially systemic infections, occur in the early stages. Most of them have infected lesions or recent infection history. They often have slow pulses. Although the body temperature is sometimes increased, most of them are normal. Cerebrospinal fluid protein is often higher than leukocytes. Ultrasound of the brain may show the shift of the midline wave to the contralateral side and the abscess wave. CT and MR examinations may have their more characteristic manifestations. Detailed medical history and comprehensive examination can be identified. The diagnosis can only be confirmed when individual difficult to identify patients undergo surgical exploration.

2. Cerebrovascular accident

Some temporal lobe tumors, especially glioblastoma multiforme and metastases, can produce intratumoral hemorrhage, necrosis, cystic changes and sudden coma, like stroke, especially when the patient has hypertension and arteriosclerosis. It is easy to be regarded as a cerebrovascular accident and ignore the diagnosis of intracranial tumors. However, its clinical manifestations are still relatively slow compared with accidental cerebrovascular hemorrhage, and most of them are accompanied by symptoms of increased intracranial pressure before the onset of the disease, and the condition gradually worsens. Emergency CT or MR is helpful for differential diagnosis.

3. Sphenoid ridge tumor

The most common tumor at the sphenoid ridge is meningiomas. According to the location of the tumor, there are three parts: the outer 1/3, the middle 1/3, and the inner 1/3 of the sphenoid ridge. When the tumor is huge, the temporal lobe can be compressed, and corresponding local signs such as mental symptoms appear. Skull plain radiographs showed bone destruction or hyperplasia at the corresponding site. Cerebral angiography and CT / MR examinations have characteristic changes, which are easily distinguished from temporal lobe tumors.

Temporal lobe tumor treatment

Temporal lobe tumors are mostly gliomas and meningiomas, and surgery is the first choice. Meningiomas are benign tumors, and can be cured if they can be completely removed by surgery. If there are residuals, postoperative stereotactic radiation therapy is also effective. However, the surgical effect of gliomas depends not only on the thoroughness of the surgery, but also the pathological type of the tumor. Generally speaking, the prognosis of low-grade (grade 1-2) glioma is better, but high-grade (3 Grade ~ 4) has a poor prognosis.