Sella vacuoles

Introduction Under normal circumstances, the saddle and the pituitary gland are closely attached, and there is almost no gap. When various pathological factors lead to deformation of the sella (saddle partition defect), enlargement or atrophy of the pituitary gland becomes smaller, the gap between the central saddle of the sella and the pituitary gland enlarges, forming a "cavitation"-like change, which may be caused by cerebrospinal fluid. The transient increase in pressure causes open passages between the sella and the oral cavity during embryonic period. A small number of patients with hypopituitarism may present with mild gonads and hypothyroidism, and hyperprolactinemia. The function of the posterior pituitary is generally normal, but diabetes insipidus can occur in some children. Children may be associated with skeletal dysplasia syndrome.

Cause

1. Primary empty saddle: Primary empty saddle refers to non-saddle surgery, radiation therapy or pituitary infarction, but because the saddle hole (ie funnel hole) becomes larger, can not be filled by the pituitary stalk, resulting in saddle The subarachnoid space is inserted into the saddle fossa through this pore. According to autopsy data, the incidence of primary empty saddle was 5.5% to 23.5%. The cause of the disease is not fully defined and may be related to the following factors:

(1) Congenital saddle development defects: On the basis of the developmental defects of the saddle, the pulsatile pressure of the cerebrospinal fluid into the saddle increases, and under the continuous action of this pressure, the arachnoid is pushed into the saddle. However, according to many data, normal people have more than 20% of saddle defects or dysplasia. However, the saddle syndrome is not necessarily present, so the defect of saddleback development is not the only factor causing the vacuolar saddle.

(2) An empty saddle occurs after the enlarged pituitary gland is reduced: for example, women often have a 2 to 3 times increase in pituitary gland during pregnancy, which may cause saddle hole and pituitary support, and postpartum (especially multiple pregnancy) pituitary recovery And shrinking, you can cause empty saddles. Primary hypothyroidism is relieved by negative feedback, which can increase the pituitary gland. After thyroid hormone replacement therapy, the pituitary body shrinks due to negative feedback inhibition, which may also cause empty saddle. However, according to the literature, it is rare to see the situation. It should be noted that prolactinoma is a relatively common tumor. Occasionally, after the application of dopamine agonists, the adenoma (generally a large adenoma) shrinks and causes a saddle or even a pituitary apoplexy. It has also been reported in the literature that prolactin giant adenoma spontaneous degeneration can cause the third ventricle to break into the enlarged saddle fossa, leading to empty saddle, sudden intracranial hypertension symptoms, cerebrospinal fluid examination showing aseptic meningitis-like abnormalities, worthy of alert.

(3) increased intracranial pressure: obesity syndrome, chronic congestive heart failure, benign intracranial hypertension (also known as pseudo-brain tumor), hypertension, hydrocephalus and other intracranial diseases, can cause increased pressure on cerebrospinal fluid, And the third ventricle can be enlarged, and the subarachnoid space is compressed, especially on the basis of the defect of the saddle and the enlargement of the saddle hole, and the subarachnoid space is more likely to be pushed into the saddle socket.

(4) Arachnoid adhesions in the sellar region and arachnoid cysts on the saddle: Such arachnoid lesions can cause local drainage of cerebrospinal fluid, even if the normal cerebrospinal fluid pressure can be depressed by the continuous impact of the saddle, and then the defect is open. After a certain degree of sputum, the subarachnoid space and the anterior lower part of the third ventricle can be inserted into the saddle fossa.

(5) Hypothalamic-pituitary disease: In the past, it was thought that rare lesions with pituitary blood supply and autoimmune pituitary insufficiency caused by pituitary atrophy may occur in the saddle syndrome. It is also not uncommon to note that in the adolescents, empty saddles due to hypothalamic-pituitary disease are not uncommon. Cacciari et al observed 339 children and adolescents with growth hormone deficiency, diabetes insipidus, secondary gonadal insufficiency, delayed puberty, precocious puberty or multiple pituitary hormone deficiency, of which 10.9% were subjected to magnetic resonance imaging. The examination confirmed that there is an empty saddle, which should cause attention, so as to avoid delaying diagnosis and treatment of the saddle syndrome, resulting in hypothalamic-pituitary hypofunction and visual impairment. Later, Bianconicini et al analyzed 71 cases of empty saddle syndrome in a group, and found 57 cases (80.2%) had mental disorders, such as anxiety or depression with behavioral disorders, and several patients with hypothalamic diseases were highlighted as Mental disorders and obesity. To this end, the authors put forward a hypothesis that the saddle syndrome may be a "new" hypothalamic syndrome. A series of hormones and neurotransmitter secretion may be caused by compression of the subarachnoid space or pulling of the pituitary gland and/or pituitary stalk. Such as leptin, neuropeptide Y (NPY), Orexins, opioid melanocyte corticosteroid (POMC) derived peptides.

(6) Others: Mucopolysaccharide storage disease, masculinization, gonadal dysplasia, renal tubular acidosis, some chromosomal abnormalities, and pointed-to-finger (toe) malformation (Carpenter syndrome) have been reported in the literature. Occasionally, it can coexist with the empty saddle, but its causal relationship is still unclear. Kalman syndrome (Kallmann syndrome) can be complicated by empty saddle syndrome. It may be due to the fact that the disease has a defect in the midline of the brain. Poor sinus dysplasia may be the pathological basis of the empty saddle.

2. Secondary empty saddle: Secondary empty saddle generally refers to the tumor caused by surgery or radiotherapy in the saddle, especially when accompanied by increased intracranial pressure, whether accompanied by hydrocephalus, can cause secondary Sexual saddle syndrome. In addition, intra-saddle tumors, especially pituitary giant adenomas, are degenerated and necrotic. A void is formed in the saddle, and the subarachnoid space is pulled due to local adhesion of the saddle due to inflammation in the area. The cystic changes in the saddle or the saddle cysts expand upward, destroying the saddle, communicating with the subarachnoid space, can also cause empty saddle. Secondary empty saddle is more likely to be complicated by pituitary insufficiency, and it is easy to postoperatively treat the optic nerve due to scar contraction and cause visual field defect or visual disturbance due to scar contraction. Be careful not to mistake the tumor for recurrence and erroneously perform radiation therapy. Examination, if confirmed as empty saddle syndrome can avoid inappropriate treatment.

an examination

Related inspection

EEG examination of brain CT

1. X-ray examination: Sella plain film and body layer film: typical morphological changes accounted for 75%, such as:

(1) Deformation: The lateral position shows that the sella is enlarged, and when the sphenoid sinus is dysplastic, the depth of the saddle is enlarged and oval. When the sphenoid sinus develops well, the saddle enlarges into a rectangle. The positive position shows that the bottom of the saddle is uniformly symmetrical and concave.

(2) Bone quality changes in the saddle floor: On the lateral position, the saddle bottom bone uniformity is thickened in the empty saddle, and the saddle bottom bone is thinner in the pituitary adenoma.

2. Cerebroencephalography (PEG): shows that there is gas filling in the saddle, and occasionally the pituitary is crescent-shaped and pushed into the lower part of the saddle.

3. Carotid angiography: Failure to show the expansion of the existing saddle tumor to the saddle helps to deny the presence of pituitary adenoma.

4. Isotope brain pool angiography: Only those who have cerebrospinal fluid rhinorrhea need to perform this test.

5. CT scan and magnetic resonance imaging: High-resolution CT coronal or magnetic resonance imaging can make a rapid and non-invasive diagnosis. The typical image shows that the saddle is enlarged, the pituitary gland is atrophied, and it is replaced by the same low-density cerebrospinal fluid as the upper saddle. If a contrast-enhanced direct coronal CT scan is used, no enhancement is seen. In severe cases, the pituitary gland is severely compressed and is flanked to the posterior and posterior, and the pituitary stalk can reach the saddle bottom to form a characteristic "funnipotrum".

Differential diagnosis

Differential diagnosis of the saddle vacuole:

1. Sella deformation: The empty saddle is the subarachnoid space that is inserted into the saddle from the junction between the saddle and the pituitary stalk. The cranial fluid is filled, which causes the saddle to expand and deform, and the pituitary is compressed and flattened. Empty sella syndrome (ESS) refers to syndromes in which the sella is enlarged and the pituitary tissue is squeezed, including headache, visual impairment, cerebrospinal fluid rhinorrhea, endocrine dysfunction, hypertension, and obesity.

2, the growth and absorption of the sella: more common in pituitary tumors, craniopharyngioma, meningioma, pituitary adenocarcinoma and increased intracranial pressure caused by various reasons.

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