intracranial lipoma
Introduction
Introduction to intracranial lipoma Intracranial lipoma is an adipose tissue tumor caused by abnormal development of embryos in the central nervous system. Intracranial lipoma rarely causes clinical symptoms. It is found in autopsy and is an intracranial tumor rarely seen in clinical practice. basic knowledge The proportion of illness: 0.002% Susceptible people: no special people Mode of infection: non-infectious Complications: spina bifida funnel chest cleft lip
Cause
The cause of intracranial lipoma
Causes
Congenital malformation (35%):
Intracranial lipoma often associated with other central nervous system congenital malformations, such as corpus callosum loss, spina bifida, localized bone defects in the midline of the skull, or spinal cord bulging, with corpus callosum being the most common.
Congenital cranial nerve abnormalities (35%):
Because lipomas occur mostly in the vicinity of the central axis, and often combined with incomplete deformity of the neural tube, many scholars believe that the cause of this disease is caused by embryonic developmental confusion and incomplete neural tube closure.
Pathogenesis
The pathogenesis of intracranial lipoma is still unclear, and there are several views on its pathogenesis:
1. Intracranial lipoma is a congenital tumor similar to hamartoma. It is a tissue ectopic malformation during fat development and grows with the development of the human body. Most scholars support this view. Intracranial lipoma is often accompanied by Malformations of neural tube dysplasia also support this view.
2. Coexisting malformations are not the cause of intracranial lipoma. There are genetic factors between them. Intracranial lipoma is a genetically related arachnoid abnormal differentiation.
3. Intracranial lipoma is formed by adipose tissue in the connective tissue and glial steatosis.
In short, its mechanism needs to be further studied.
In pathology, lipomas are mostly located in the subdural or cerebral cisterns, and the boundaries are unclear. With a large number of fibers and blood vessels intertwined with nerve tissue, the corpus callosum can be a thin layer that diffusely covers the corpus callosum or lies vertically. The corpus callosum is in the median fissure. The histological examination is mainly based on fully differentiated mature fat cells. There are also fetal adipose tissue. There may be foamy powdery substances in the cells. It is not easy to see the nucleus, and the size is different. There are no signs of malignancy. Often accompanied by other structures, such as a large number of fibrous tissue and blood vessels, the size of the blood vessels are different, the arrangement is more disordered, the wall thickness is thickened, the smooth muscle is enlarged, and a large amount of collagen fibers can be formed in the fibrous tissue, and the blood vessels are surrounded. Leaf cells grow and accumulate, and some still contain striated muscle, bone and bone marrow tissue.
Prevention
Intracranial lipoma prevention
The patient recovered well after partial surgical resection. Because most patients with lipoma do not have fatal intracranial pressure and fatal mass lesions, most do not require surgery.
Complication
Intracranial lipoma complications Complications spina bifida fungus chest cleft
This disease is often associated with other malformations of neural tube dysplasia, the most common with corpus callosum lipoma, 48% to 50% of corpus callosum lipoma with dysplasia or lack of stenosis, other common malformations have a transparent septal defect, spina bifida, ridge Membrane bulging, skull dysplasia (frontal, parietal defect), cerebellar stenosis, etc., rare deformities include funnel chest, hard sacral high arch, septal defect, cleft lip, subcutaneous lipoma or fibroid.
Symptom
Intracranial lipoma symptoms Common symptoms Skull hyperplasia intracranial pressure increased tinnitus corpus callosum dysplasia retarded dementia vertigo mental disorder ataxia hearing loss
Most intracranial lipomas are small, mostly below 2cm, and are often found by chance during autopsy or CT scan. The symptoms of this disease progress slowly, and the course of disease is longer, up to 10 years. Even symptoms can be relieved by themselves. When lipomas are not Neurological symptoms and signs are generally not present in important functional areas of the brain. The clinical manifestations of intracranial lipoma lack specific symptoms and signs, and 10% to 50% of patients are asymptomatic.
1. Epilepsy This is the most common symptom of intracranial lipoma, accounting for about 50%. It can be used for various types of epilepsy, but it is mainly caused by a large seizure. The seizure may be accompanied by a gelatinous degeneration that stimulates brain tissue or fat. The dense fibrous tissue in the tumor capsule is infiltrated into the peripheral nerve tissue, forming an excitatory foci; it may also be related to corpus callosum dysplasia or lipoma itself.
2. Brain localization of intracranial lipoma rarely causes brain localization, sometimes it can oppress the surrounding structure and appear corresponding positioning signs, such as corpus callosum lipoma compression of the hypothalamus, hyponatremia, obesity, reproductive incompetence and other symptoms of diencephalic damage ; bridge cerebellar horny lipoma can occur tinnitus, hearing loss, dizziness, trigeminal neuralgia, nystagmus, ataxia, etc.; sellar lipoma can cause endocrine disorders and vision, visual field changes, etc., medullary cervical spinal dorsal lipoma can The performance is numbness of the limbs, medullary paralysis, progressive aggravation, accompanied by transient pain in the chest, shoulder and neck pillow, dysfunction of the bowel and bladder, increased muscle tension in the limbs, decreased muscle strength, bilateral pathological signs positive; Insular lipoma can have a hook-back episode, limb weakness and so on.
3. Increased intracranial pressure in the ventricle choroid plexus lipoma, which can block the cerebrospinal fluid circulation caused by interventricular pores or the tetracycline lipoma compresses the middle cerebral aqueduct to cause obstructive hydrocephalus and increase intracranial pressure, such as headache. Vomiting, optic disc edema, etc.
4. Other symptoms About 20% of patients have different levels of mental disorders, and even dementia, may be due to tumor involvement of bilateral frontal lobe, manifested as apathy, slow response, no desire, memory loss, urinary incontinence, etc., body fat Tumor mental disorders can reach 20% to 40%, palsy accounts for 17%, and headaches account for 16%.
5. Associated with malformation See the complications section for details.
Examine
Examination of intracranial lipoma
1. Skull plain film typical corpus callosum lipoma X-ray film can be seen in the midline structure of "wine-shaped" or "shell-like" calcification, this typical sign can be used as a basis for the diagnosis of intracranial lipoma, cerebellopontine lipoma Sometimes there may be an internal auditory canal enlargement and a sacral defect, etc. The X-ray tomogram can clearly show that the lipoma has a large number of translucent areas through the X-ray, and the skull can still show a combined brain malformation, such as Skull dysplasia, bone defects and so on.
2. Cerebral angiography In the internal carotid artery angiography, corpus callosum lipoma can present the anterior cerebral artery tortuous expansion, sometimes the bilateral anterior cerebral arteries are combined into one, the temporal artery, the periorbital artery also expands accordingly, and many small lipomas are supplied. Branched into parallel mesh, anterior cerebral artery, iliac artery is often wrapped by tumor, bridge cerebellopontine lipoma, cerebral angiography can be seen in the anterior inferior cerebellar artery and its branches, cerebral angiography can also show coexistence, Such as corpus callosum dysplasia, hydrocephalus and venous drainage abnormalities.
3. CT examination of lipoma CT findings of a round, circular or irregular low-density area, CT value of -110 ~ -10Hu, its edge is clear, low-density stoves can have layered calcification, after strengthening The low-density area is not enhanced, the CT value is not significantly increased, and the diameter of the low-density area is more than 2cm. The coronary scanning calcification layer is more clear. The calcification is more common in corpus callosum lipoma, and the calcification of lipoma in other parts is rare. Sometimes it can be found. Multiple lipoma, especially in the lateral ventricle choroid plexus, 25% of patients with corpus callosum lipoma can see the second lipoma in the choroid plexus. Other CT manifestations of lipoma include corpus callosum dysplasia, lateral ventricle separation, lateral ventricle choroid plexus Tumors, etc.
4. MRI MRI is the best method for diagnosing lipoma. Both T1-weighted images and T2-weighted images show high signals, and calcification on the wall of lipoma sometimes shows no signal.
MRI of cerebral hemisphere interstitial (sacral) lipoma can show:
1 A fat lumps that are almost symmetric in the midline, occupying a localized area of the hemisphere, usually near the corpus callosum;
2 showing different degrees of extension around the corpus callosum, the choroidal fissure to the choroid plexus, distributed along the cerebral palpebral;
337% to 50% are accompanied by corpus callosum dysplasia;
411% were accompanied by subcutaneous lipoma;
5 surrounding the hemispherical artery to form a fusiform expansion;
6 lipoma peripheral shell calcification or contains dense bone.
Diagnosis
Diagnosis and identification of intracranial lipoma
Diagnostic criteria
Because there is no specific clinical manifestation of intracranial lipoma, it is very difficult to diagnose clinical manifestations alone. For patients with long-term seizures and mental retardation, neuroradiology should be performed. According to the predilection site, the fat-like low density on CT The T1 and T2 weighted images on the region and MRI are high signals, and the diagnosis can be established.
Differential diagnosis
Intracranial lipoma needs to be differentiated from dermoid cysts, epidermoid cysts, teratomas, arachnoid cysts, chronic hematoma, craniopharyngioma, and corpus callosum glioma.
Dermoid cysts, epidermoid cysts, and arachnoid cysts all showed a low-density area with no enhancement of CT, but the T1-weighted image on MRI was low-signal, which was different from that of lipoma.
The MRI findings of epithelioid cysts and lipomas are both T1 and T2-weighted high-signal signals, but the former have more bone fractures and bone destruction, which can be found by CT scan.
Teratoma CT showed a heterogeneous cystic mass with a tumor diameter of more than 2.5 cm.
