Craniopharyngioma is a relatively common benign intracranial tumor. It is classified as suprasellar cyst, ependymoma, epithelial cyst, squamous epithelioma, pituitary duct ependymoma, enucleinoma, and pituitary enucleinoma depending on the site of occurrence and histology. They are mostly seen in young people and children, with a male to female ratio of about 2:1.
Craniopharyngioma is well defined from the surrounding tissues, but its size, shape and growth range vary greatly. The largest ones are like cobblestones, while the smallest ones are as big as peanut rice. The shape is diverse, including spherical, irregular and nodular. Most of them are cystic in nature, and the substantial ones are not seen. The thickness of the cyst wall varies greatly, some are as thin as window paper, and the color of the fluid inside the cyst is visible through the thin wall, mostly yellowish brown. Some cysts have thicker walls with grayish white color and many calcified spots, which are characteristic of craniopharyngioma. The cyst wall is usually free and does not adhere to the surrounding tissue. If the tumor is substantial or partially substantial, it may sometimes adhere to important structures at the base of the skull, causing compression and corresponding clinical symptoms, such as compression of the pituitary stalk, subthalamic sinus, cavernous sinus, optic cross and internal carotid artery.
Craniopharyngioma occurs most often in the pituitary nodes, but also in the anterior part of the third ventricle and in the saddle, and least often in the pterygoid sinus. Tumors located in the suprasellar region tend to grow toward the third ventricle, while those in the saddle may develop toward the suprasellar region. Small cysts that develop between the anterior and posterior lobes of the pituitary gland in the gap between the overlying epithelium have also been included in the scope of craniopharyngioma. Compression of the optic cross is usually caused by suprasellar tumors or intra-saddle tumors developing suprasellarly. Suprasellar tumors may protrude into the third ventricle and enter the lateral ventricles through the interventricular foramen. It is not uncommon for tumors to develop at the base of the frontal lobe and the base of the temporal lobe, and some even grow posteriorly to compress the midbrain and pons. In general, substantial tumors are closely adherent to surrounding tissues, hard and calcified, and some of them may become malignant and metastasize.
Microscopically, the inner side of the tumor cyst wall is composed of multiple layers of squamous epithelioid tumor cells, which may be distributed in clusters with stellate cells in the center. The periphery is surrounded by fibrous tissues, and within the fibrous tissues, keratinized material and degenerated tissues of the Erythroderma can be seen, and within the wall, calcification and even ossification can be seen in an irregular shape. Also intracapsular fluid was seen with phagocytes and cholesterol crystals, as well as foreign body giant cells. Glial cell proliferation around the tumor.
Depending on the location of the tumor, the speed of growth, the direction of development and the age of the patient, the clinical manifestations are also different. Commonly, they can appear: visual field changes, increased intracranial pressure, endocrine dysfunction and changes in consciousness.
Clinical manifestations:
1. Visual field change: It is not uncommon to have visual field disorder as the first symptom, accounting for about 18% of craniopharyngioma. The change of visual field is caused by the upward development of tumor in the saddle or suprasaddle, which directly presses the visual fiber. In particular, compression of the visual cross-section is more common, resulting in primary optic nerve atrophy, leading to vision loss or even complete blindness. Due to the different compression sites of the visual pathway, the clinical manifestation is different visual field defects, which are mostly irregular, monocular or binocular. If one eye is normal or blind, the other eye shows temporal hemianopia, bilateral temporal hemianopia, isotropic hemianopia, centripetal reduction of visual field in both eyes, or hemianopia in the superior temporal quadrant. In children, it is often difficult to determine the change of visual field because they cannot describe the visual field or are uncooperative during the examination.
2. Increased intracranial pressure: Increased intracranial pressure in craniopharyngioma is mostly seen in children and can be the first symptom, which is also the reason for the patient’s visit. The reason for this is that the tumor is large in size and blocks the circulatory pathway of cerebrospinal fluid. Clinical manifestations include headache, nausea and vomiting, optic nerve papillary edema, diplopia, and neck pain. In children and young adults, there may be cranial suture splitting, cranial enlargement, and “broken pot” sound when tapped. Almost all patients have headache, most of them are the first symptom, and most of them are accompanied by vomiting. The reason for this is that the tumor is large, or grows into the third ventricle and obstructs the interventricular foramen, which causes the fluid in the lateral ventricles to increase the intracranial pressure.
3.Endocrine disorder: 2/3 of the patients with craniopharyngioma have endocrine disorder symptoms. The symptoms include hypogonadism, water and fat metabolism disorders and growth retardation.
In men, hypogonadism is manifested as low libido and impotence. Patients have thin skin, reduced basal metabolism, weakness, a shrill voice, and a sparse beard in adults. In male adolescents, the sexual organs may not develop and secondary sexual characteristics are lacking. In women, menstruation may never occur or may stop. This is mainly due to the disruption of the anterior pituitary gland and impaired secretion of gonadotropins. Since the hypothalamus and anterior pituitary gland are related to fat metabolism, when they are compressed or destroyed by the tumor, the patient will have abnormal fat distribution, resulting in obesity, which is centripetal in nature. Due to the low function of anterior pituitary gland, the secretion of growth hormone is impaired and growth hormone is lacking, which leads to delayed growth and development, which manifests as dwarfism. About 1/3 of the patients present with urolithiasis. Patients have polyhydrosis and polyuria, with a daily urine volume of 3000-4000 ml and low specific gravity. This is caused by the destruction of nerve fibers in the hypothalamus and the posterior pituitary gland, resulting in impaired secretion and release of antidiuretic hormone. In addition, some patients may have drowsiness, coma, and hypothermia or hypothermia due to hypothermia.
4. Changes in consciousness: Some patients may have disorders of consciousness, which may appear as indifference or drowsiness, and a few may appear as coma. This may be due to damage to the lower thalamus and compression of the midbrain due to the occurrence of brain herniation.
5.Change of optic nerve papilla: Due to the increase of intracranial pressure, the patient will have edema of optic nerve papilla, which will lead to optic nerve atrophy, vision loss and blindness. If the tumor directly presses the optic nerve, it will produce primary optic nerve atrophy. Individual patients may have normal optic papillae.
Medical history, symptoms and signs.
Endocrine dysfunction: hypopituitarism, sexual dysfunction and dwarfism are more common; upward development of tumor compressing hypothalamus may cause hypothalamic syndrome, precocious puberty or neurogenic amenorrhea, overflow-amenorrhea syndrome, cortisolism, hyper- or hypothyroidism, acromegaly, gigantism, dwarfism, uremia, polyphagia, obesity or anorexia, fever or hypothermia, drowsiness or insomnia. Insomnia, some of them may have mental excitement, hallucinations and disorientation.
2, intracranial pressure increase syndrome: headache, nausea, vomiting, impaired consciousness, drowsiness. Children may show hydrocephalus.
3.Symptoms of optic nerve compression: gradual loss of vision, hemianopia, and blindness over time.
4, other symptoms: headache, facial sensory loss, mild hemiparesis.
Laboratory tests.
1. In hypopituitarism, gonadotropin and growth hormone are significantly decreased, thyroid hormone and TSH are reduced; basal metabolic rate is decreased; glucose tolerance is often reduced;
2, cerebrospinal fluid pressure is increased, white blood cell count and protein amount may be mildly increased.
3.Cranial X-ray: calcification in the saddle area, enlargement and destruction of the pterygoid saddle.
4.CT and MRI scan: Tumor can be seen in the saddle area.
5.Cerebral angiography: show suprasellar tumor.
Differential diagnosis.
It should be differentiated from pituitary adenoma, optic nerve glioma, optic cross arachnoiditis, etc.
Treatment plan:
1.Surgical treatment: total resection is suitable for intra-saddle tumor, and partial resection is feasible for those with less severe pressure on optic nerve and cranial pressure, but the recurrence rate is higher.
2.Radiotherapy has certain efficacy.