Craniopharyngioma is a tumor formed by the growth of remnant epithelial tissue of the craniopharyngeal duct during embryonic life. The craniopharyngeal duct is a duct formed during embryonic development to form the precursor of the pituitary gland, the Rattaker’s bursa, which closes and disappears when it matures. If the development is abnormal, the residual epithelium of the Rattler’s bursa proliferates and forms a craniopharyngioma. The tumor grows slowly and is located at the tip of the pituitary gland, growing upward above the saddle septum, compressing the optic nerve and optic cross, protruding backward into the third ventricle, compressing the lower thalamus, and invading downward into the pterygoid saddle, and may destroy the saddle base into the pterygoid sinus. It can occur at any age, but most of the cases occur under 15 years old and are benign tumors.
I. Symptoms and signs
Early symptoms are not obvious, but the tumor grows and compresses the surrounding brain tissues, the common symptoms are.
1. Endocrine disorders: the tumor compresses the pituitary gland or hypothalamus, children show slow growth and growth retardation (pituitary dwarfism), adults show obesity, low sexual function, weakness, low basal metabolic rate, etc.
2, vision and visual field changes: tumor compression of optic nerve and optic cross caused vision loss and visual field defects.
3.Increased intracranial pressure: the tumor protrudes into the third ventricle and blocks the interventricular foramen, causing increased intracranial pressure.
Intracranial hypertension is the first symptom in children and adolescents, and optic nerve compression is the most common symptom in adults. All patients may have endocrine changes, but adults appear earlier.
II. Diagnosis
The disease should be differentiated from saddle area dermatomatous cyst, chordoma, teratoma and meningioma, and the final diagnosis depends on postoperative pathological examination.
1, astrocytoma: astrocytoma above the third ventricle often appears as a solid mass in the suprasellar area, which usually does not extend into the saddle, and the calcification rate is lower than that of craniopharyngioma. However, it is sometimes difficult to distinguish from suprasellar parenchymal craniopharyngioma.
2.Meningioma: 10% of meningiomas occur in the saddle, with uniform and slightly dense scan, calcification may be present, cystic changes are rare, the tumor is often located in the anterior position of the saddle, and the saddle node is osteophytic.
3.Pituitary tumor: it can protrude to the saddle, often cause the butterfly saddle to expand, the saddle sinks, the cavernous sinus is involved, and cystic change occurs due to hemorrhage and necrosis. But calcification is rare.
4.Aneurysm of huge aneurysm may have calcification on the wall, and the wall of the aneurysm is strengthened by the organic tissue during the enhancement scan, but the reinforcement is very significant where there is blood in the cavity of the aneurysm, which is consistent with the reinforcement of the intracranial artery. If it cannot be distinguished, MR examination or cerebral angiography should be performed.
Examination methods
1.Laboratory examination.
(1) Growth hormone measurement and GH excitation test: patients with craniopharyngioma have reduced serum GH value and no significant elevation in response to insulin hypoglycemia, arginine, levodopa and other excitation tests.
(2) Gonadotropin urotropin, luteinizing hormone assay and GnH excitation test: patients with craniopharyngioma had reduced serum FSH and LH levels and did not respond significantly to gonadotropin-releasing hormone excitation test, suggesting that the tumor had invaded the hypothalamic-pituitary region.
(3) Prolactin measurement: serum PRL level of patients may increase probably due to tumor blocking the entry of prolactin-releasing inhibitory hormone (PIH) into the pituitary gland, resulting in increased secretion and release of PRL.
(4) Clearance tests: Adrenocorticotropic hormone ACTH and thyrotropic hormone TSH are measured when the tumor severely compresses the pituitary tissue and atrophies, the patient’s serum ACTH and TSH are reduced.
(5) Anti-diuretic hormone (ADH) measurement: serum ADH is often reduced in patients with craniopharyngioma.
2.Other auxiliary examinations.
Cerebral angiography: It shows the displacement of blood vessels in different directions due to the compression of cerebral blood vessels by tumor. The main sign of cerebral angiography for suprasellar or intra-saddle to suprasellar tumors is the upward and backward displacement of the anterior cerebral artery. Posteriorly growing tumors may compress the basilar artery and cause it to shift posteriorly. When the tumor grows into the third ventricle, hydrocephalus-like vascular changes may appear, i.e., the lateral fissure artery is displaced outward and the anterior cerebral artery is shifted upward vertically. Brain CT examination: CT can show the location, size and shape of tumor, especially many craniopharyngioma will have calcification CT can show these calcifications well, and also can see the flattening of the pterygoid saddle, damaged bed protrusion, enlarged pterygoid saddle and other manifestations, which can provide a reliable basis for the diagnosis of craniopharyngioma. MRI of brain: Most craniopharyngioma cystic part is short T1 and long T2 signal, also can show long T1 and long T2 image; substantial craniopharyngioma, is long T1 and long T2. calcified spot shows low signal area.
CT and MRI examinations are important for the diagnosis, which can show the location and size of the tumor, the presence of cystic changes, the invasion of the tumor into the adjacent brain tissue, and the presence of hydrocephalus.
MRI is a necessary examination item, which takes priority over CT in showing the structure of tumor and its relationship with adjacent brain tissues (such as optic cross), but cannot show calcified foci like CT.
Treatment
1.Surgical resection: total resection or subtotal resection is possible, but the effect of craniopharyngioma is often unsatisfactory because of its close connection with internal carotid artery, optic nerve and other surrounding tissues and the infiltration of large tumor into surrounding tissues. The improvement of symptoms after surgery is also unsatisfactory. Fractional microsurgery can minimize complications and have a significant effect on the improvement of patients’ symptoms.
2.Radiotherapy: Radiation therapy has good effect on prolonging the recurrence time after surgery, but the risk of radiotherapy should be fully estimated. There are reports of complications such as radiation brain necrosis, endocrine depression, optic neuritis and dementia.
3.Psychological construction: Craniopharyngioma mostly occurs in children and young people, who have poor psychological tolerance and are prone to fear and pessimism once they are diagnosed. In addition, craniotomy has a certain degree of danger, and patients often feel uneasy, afraid and irritable, which affects rest and sleep, and even refuse to operate. For this reason, nurses should patiently answer patients’ various questions, relieve patients’ ideological concerns, and introduce successful cases to build patients’ confidence to overcome the disease.
V. Complications
They can be divided into hypothalamic damage, hypopituitarism, visual field disorder and other symptoms. Complications after hypothalamic damage are complicated with an incidence of 80%, including abnormal hormone levels, uremia, thermoregulation, stress gastrointestinal bleeding, disorders of consciousness, circadian rhythm disorders, respiratory rhythm disorders, increased blood sugar, abnormal appetite, mental abnormalities, circulatory failure, acute pulmonary edema; hypopituitarism has an incidence of 47, 62%; postoperative visual acuity is diminished or aggravated in 13, 33%. Other cases include aseptic meningitis, cerebrospinal fluid nasal leakage, and epilepsy.