Epidermoid cyst

Introduction to epidermoid cyst Epidermoid cysts, also known as cholesteatoma, are also called pearlomas because of their whiteness like white pearls. When the embryonic neural tube is closed, the ectoderm component is mixed, and the growth gradually leads to tumor formation. That is, the skin epidermal cell layer remains, and the epithelial tissue constantly renews the keratinized cells, so that the contents of the cyst gradually increase and form a tumor. Epidermoid cysts are benign lesions that can occur in the spine or in the brain. The lesion can occur in the epidural (usually outside the midline) or epidural (usually in the cranial occlusion space). The intracranial epidermoid cyst accounts for 0.2-1.8% of the intracranial tumor. basic knowledge Probability ratio: Susceptible people: no specific people Mode of infection: non-infectious Complications: meningitis

Epidermoid cyst etiology

Congenital factors (65%)

In 1936, Love and Kernohan first described epidermoid cysts as congenital epithelial tumors. Later studies confirmed that the tumor was abnormally grown with ectopic epithelial cells when the neural tube was closed. Dia and Walker first proposed that this is an abnormal variation in the embryonic stage of the embryo formation, and that the third to fourth weeks of embryonic development interfere with neural tube closure.

Trauma (25%)

Because lumbar puncture is one of the commonly used examination methods in neurology, it is of great value, simple and safe for the diagnosis and treatment of nervous system diseases. However, if the indications are not properly controlled, it can cause concurrency. disease. In 1954, Choremis noticed a epidermoid cyst after the lumbar puncture, thus supporting the theory of the cause of trauma.

Epidermoid cyst prevention

Disease prognosis

It is a benign tumor, and it recovers well after surgery. For example, most tumors can be resected, and the recurrence is late, which can be extended to several years or decades. The incidence of malignant transformation is very low, with only a few reports.

Epidermoid cyst complications Complications meningitis

Postoperative complications, postoperative cysts containing fatty acids and cholesterol spills caused by aseptic meningitis is a common complication.

Epidermoid cyst symptoms Common symptoms Visual impairment Ataxia cerebral cerebellopontine angle syndrome Tibial bulge Secondary epilepsy Drinking vision defect Tinnitus Hearing loss Facial muscle weakness

Multiple groups

Epidermoid cysts can occur at all ages and can even be found at autopsy. It can occur in the spine or in the skull in position. The average age of onset is 35 years old, and female patients are more common.

Disease symptoms

Corresponding clinical manifestations occur depending on the site of tumor growth.

1, bridge cerebellar epidermoid cyst: the most common site, often with trigeminal neuralgia (70%), often with ipsilateral tinnitus, deafness, late cerebellopontine angle syndrome. The nervous system found that V, VII, VIII cranial nerve dysfunction, manifested as facial sensation, facial muscle weakness, hearing loss and ataxia, a small number of patients with glossopharyngeal nerve, vagus nerve palsy, etc. Epidermoid cysts can also cause cranial nerve dysfunction in V and VIII.

2. Epidermoid cyst in the sellar region: The symptoms caused by the tumor located on the saddle are similar to those of the pituitary tumor. The visual acuity and visual field defect are often used as early clinical manifestations, and the optic nerve atrophy can be caused for a long time. A small number of patients have endocrine disorders, which are characterized by hypofunction of the pituitary and hypothalamic lesions such as sexual dysfunction, polydipsia and polyuria. The development of the tumor may lead to frontal lobe symptoms, and the sudden intrusion into the third ventricle may have symptoms of increased intracranial pressure, and the general condition progresses slowly.

3, epidermoid cysts in the brain parenchyma: the brain, cerebellum and brain stem can be the site of the disease. According to the location of the tumor, the corresponding symptoms appear. Cerebral hemisphere tumors often have seizures, mental symptoms and hemiplegic symptoms. Cerebellar tumors often have nystagmus, ataxia, etc., brain stem tumors have cross paralysis, disease side VI, VII cranial nerve palsy and contralateral compulsory Lightly biased. 4, ventricle epidermoid cysts rarely use symptoms in the early stage, generally more common in the lateral ventricle triangle area and horns, can grow very large, and even fill the ventricles, block cerebrospinal fluid circulation and produce symptoms of high blood pressure, tumors occur in the third ventricle, four ventricles Rare.

5, cranial epidermoid cyst: can occur in any part of the skull, but often occur in the midline or near the midline (front, pillow) or in the tibia. It is often found in the clinic that the surface of the skull has been bulged for many years, and it has a rubbery feel, no tenderness, and can be moved or fixed on the skull. The chance of a midline lesion approaching the bridge of the nose or sinus is great. This is of particular importance when the cyst expands into the brain to involve large veins or deep into the brain.

Examination of epidermoid cyst

1. Skull X-ray: A small number of cerebral cerebral horns or mid-cranial fossa tumors can be seen as apex of rock tips or rock bones. In some cases, calcification may occur, and the image is lighter. The skull of the tumor in the slab is typically osteolytic. Lesions, and showed a sharp hardening margin, it is not uncommon for people with osteomyelitis around them.

2, CT: CT scan is an effective diagnostic tool for epidermoid cysts. It helps to detect the contour and expansion of the tumor, and the cyst appears as a low-density image. Generally, it is not strengthened after the injection of the enhancer. Epidermoid cysts in the stenosis may be expansively disrupted, with sharp edges and dense density images.

3. MRI: Epidermoid cysts show a low-border low-signal on T1-weighted images, high-signal on T2-weighted images, and uneven signal intensity due to uneven tumor texture, which is characteristic of MRI. MRI of epidermoid cysts in the stenosis can show its occupancy effect and high signal imaging.

Diagnosis and differentiation of epidermoid cyst

diagnosis

According to clinical symptoms and various examinations such as skull X-ray, CT, MRI for diagnosis.

Differential diagnosis

1 teratoma: a mass mixed with fat density.

2 Dermoid cyst: in the midline, the lesion density is more uniform, often lower than the cerebrospinal fluid, and the incidence is lower.

3 arachnoid cyst: density and cerebrospinal fluid similar, and uniform, often round or oval, the shape is more regular, no visible seams.

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