| disease | Craniopharyngioma |
Craniopharyngioma is a common embryonic residual tissue tumor that develops from the epithelial cells of the remnants of the craniopharyngeal duct formed by the ectoderm. It is the most common congenital intracranial tumor. Among sellar region tumors, it ranks second in incidence, slightly lower than pituitary adenomas. It predominantly occurs in children and is less common in adults. The tumor frequently arises in the suprasellar region, accounting for 5-7% of all intracranial tumors and 12-13% of pediatric intracranial tumors. According to reports by Wang Zhongcheng and others, the highest incidence occurs at the age of 15, with the maximum age reported being 56 years and the minimum age being 1 year and 3 months. The male-to-female ratio is 2:1.
bubble_chart Pathological Changes
The boundary between craniopharyngioma and surrounding tissues is clear, but its size, shape, and growth range vary greatly. The largest can be as big as a goose egg, while the smallest is the size of a peanut. The shapes are diverse, including spherical, irregular, and nodular. Most are cystic, with no solid cases observed. The thickness of the cyst wall varies significantly—some are as thin as window paper, through which the color of the fluid inside (often yellowish-brown) can be seen. Some cyst walls are thicker, grayish-white, and dotted with calcifications, which is a characteristic feature of craniopharyngioma. The cyst wall is generally free and not adherent to surrounding tissues. If the tumor is solid or partially solid, it may adhere to critical structures at the skull base, causing compression and corresponding clinical symptoms, such as pressure on the pituitary stalk, hypothalamus, cavernous sinus, optic chiasm, and internal carotid artery.
Under the microscope, the inner side of the tumor cyst wall is composed of stratified squamous epithelial-like tumor cells, which may be distributed in clusters with central stellate cells. The periphery is surrounded by fibrous tissue, within which keratinized material and degenerated eosinophilic tissue can be seen. Calcifications, even ossifications, may be present in the wall, appearing irregular in shape. The cystic fluid may also contain phagocytic cells, cholesterol crystals, and foreign-body giant cells. Gliosis is observed around the tumor.
bubble_chart Clinical Manifestations
The clinical manifestations vary depending on the tumor's location, growth rate, direction of development, and the patient's age. Common symptoms include changes in vision and visual fields, increased intracranial pressure, endocrine dysfunction, and altered consciousness.
2. Increased intracranial pressure Increased intracranial pressure is more common in children with craniopharyngioma and may be the initial symptom, prompting medical consultation. This is usually caused by the tumor's large size obstructing the cerebrospinal fluid circulation pathway. Clinically, it manifests as headache, nausea, vomiting, optic disc edema, diplopia, and neck pain. In children and young adults, cranial sutures may split, leading to an enlarged head and a "cracked pot" sound upon percussion. Almost all patients experience headache, often as the first symptom, usually accompanied by vomiting. This is due to the tumor's size or its extension into the third ventricle, blocking the foramen of Monro and causing hydrocephalus, which elevates intracranial pressure.
Hypogonadism in males presents as decreased libido and impotence. Patients may have thin skin, reduced basal metabolism, lack of strength, a high-pitched voice, and sparse facial hair in adults. Male adolescents may exhibit underdeveloped genitalia and lack of secondary sexual characteristics. Females may experience amenorrhea or cessation of menstruation. These symptoms result from damage to the anterior pituitary, disrupting gonadotropin secretion. Since the hypothalamus and anterior pituitary are involved in fat metabolism, tumor compression or damage can lead to abnormal fat distribution, causing centripetal obesity. Impaired anterior pituitary function also disrupts growth hormone secretion, resulting in growth retardation and dwarfism. Patients show slow skeletal development and short stature, though body proportions remain normal. Despite their age, they may appear childlike, though intelligence is usually unaffected. About one-third of patients develop diabetes insipidus, characterized by polydipsia and polyuria, with daily urine output reaching 3000–4000 ml and low specific gravity. This is caused by damage to the hypothalamus or the neural fibers to the posterior pituitary, impairing antidiuretic hormone secretion and release. Additionally, some patients may experience drowsiness, unconsciousness, or impaired thermoregulation, leading to hyperthermia or hypothermia.
4. Altered consciousness Some patients exhibit consciousness disturbances, such as apathy or drowsiness, and a few may become unconscious. This may result from hypothalamic damage or midbrain compression due to cerebral herniation.
5. Changes in the optic disc Increased intracranial pressure can cause optic disc edema, which over time leads to optic atrophy, vision loss, or blindness. Direct tumor compression of the optic nerve causes primary optic atrophy. In rare cases, the optic disc may appear normal.
bubble_chart Auxiliary Examination
1. Skull X-ray Plain Film The changes in skull X-ray plain films of craniopharyngioma can be divided into two aspects: ① Skull alterations caused by increased intracranial pressure; ② Local skull changes due to tumor compression and the specific X-ray signs of the tumor itself. The former is more pronounced in children and young adults, manifesting as increased digital impressions on the inner table of the skull, shortening, decalcification, or disappearance of the dorsum sellae and posterior clinoid processes. The characteristic X-ray signs of the tumor itself include spotty calcifications, which can be single or multiple, scattered or fused into a cystic distribution, and may even appear eggshell-like. Tumor calcifications are more common in children and can be distributed in the suprasellar or intrasellar regions. Sometimes, calcifications form bony protrusions closely attached to the skull base. Wang Zhongcheng et al. reported that calcifications were present in 66% of all patients with craniopharyngioma. The sella turcica often appears basin-shaped or spherically enlarged, with the posterior clinoid processes and dorsum sellae shortened or absent. Suprasellar tumors located higher up are less likely to cause changes in the sella turcica.
2. Cerebral Angiography Due to tumor compression on cerebral blood vessels, angiography reveals displacement of vessels in various directions. The main angiographic signs of suprasellar or intrasellar tumors growing upward are upward and backward displacement of the anterior cerebral artery. Tumors growing backward can compress the basilar artery, causing it to shift posteriorly. When the tumor extends into the third ventricle, hydrocephalus-like vascular changes may occur, such as outward and upward displacement of the sylvian artery and vertical upward displacement of the anterior cerebral artery.
3. Pneumoencephalography and Ventriculography Pneumoencephalography of suprasellar tumors often shows elevation or disappearance of the chiasmatic cistern and filling defects in the anterior part of the third ventricle. If the tumor grows into the third ventricle and obstructs the foramen of Monro, the imaging reveals non-filling of the third ventricle and enlargement of the lateral ventricles. This is due to the tumor filling the third ventricle and blocking the foramen of Monro, leading to cerebrospinal fluid circulation obstruction.
4. Brain CT Scan CT can display the location, size, and shape of the tumor, providing reliable evidence for the diagnosis of craniopharyngioma.
5. Others Electroencephalography (EEG) and brain isotope examinations are also helpful in the diagnosis of craniopharyngioma.
(1) Pituitary Adenoma
1. Chromophobic Pituitary Adenoma Chromophobic pituitary adenoma is a tumor derived from the chromophobic cells of the pituitary gland, often extending upward through the diaphragma sellae. Clinically, it manifests as endocrine disturbances, changes in vision and visual fields, alterations in the sella turcica, and headache. Its clinical presentation is similar to that of craniopharyngioma, but it predominantly occurs in adults. Endocrine disturbances include decreased libido, amenorrhea, obesity, etc. The optic disc shows primary atrophy, often accompanied by bitemporal hemianopia and destruction of the sella turcica. Patients generally do not exhibit signs of increased intracranial pressure. X-ray plain films show no calcification in the intrasellar or suprasellar regions.
2. Acidophilic Pituitary Adenoma Acidophilic pituitary adenoma originates from the acidophilic cells (α cells) of the pituitary gland and may extend upward through the diaphragma sellae, compressing the optic fibers and causing changes in vision and visual fields. Unlike craniopharyngioma, the excessive secretion of growth hormone by acidophilic cells leads to: ① Acromegaly in adults due to epiphyseal fusion, clinically presenting as enlarged hands and feet, protruding jaw, enlarged nose, widened tongue, and often kyphosis, along with visceral hypertrophy. Patients exhibit coarse facial features and a deepened voice. ② In children and young adults, where epiphyseal fusion has not yet occurred, gigantism manifests, but the body develops proportionally.
(2) Optic Chiasm Glioma Gliomas of the optic chiasm originate from the glial cells of the optic chiasm, optic nerves, and hypothalamus, with astrocytomas being the most common. They are more prevalent in adolescents. Gliomas originating in the hypothalamus may grow downward to compress the optic nerves or chiasm, while those originating in the optic chiasm may extend upward into the thalamus, leading to mutual influence between these regions (gliomas of the hypothalamus and optic chiasm). Clinically, they present as headache, changes in vision and visual fields, endocrine disturbances, and hypothalamic symptoms. Headache is often localized to the frontal or temporal regions and is usually the initial symptom, accompanied by nausea and vomiting. If the tumor invades the hypothalamus and pituitary, patients may experience amenorrhea, decreased libido, polydipsia, and polyuria. Visual acuity declines, often asymmetrically between the two eyes. Visual field changes commonly include bitemporal hemianopia, homonymous hemianopia, or unilateral blindness with partial visual field loss in the other eye. The optic disc typically shows primary atrophy. Additionally, patients may exhibit drowsiness and obesity. X-ray plain films often reveal an enlarged sella turcica, with some patients showing calcification or dissipating ecchymosis in the suprasellar region, making differentiation from craniopharyngioma sometimes difficult. However, if the tumor is of the intracranial-orbital type, the presence of exophthalmos facilitates differentiation.
(3) Tuberculum Sellae Meningioma This condition clinically manifests primarily as headache, visual impairment, pituitary-hypothalamic dysfunction, and increased intracranial pressure. Visual acuity typically declines slowly and progressively, often being the most common symptom. Patients exhibit asymmetric, irregular visual field defects, or unilateral blindness with normal vision in the other eye, or unilateral blindness with temporal hemianopia in the other eye. The optic disc usually shows primary atrophy. A minority of patients develop endocrine symptoms, such as impotence or amenorrhea, only in the advanced stage. Headache is generally mild and localized to the frontal or temporal regions. Additionally, patients may experience hyposmia or anosmia, as well as dysfunction of the III and V cranial nerves. Skull X-rays may show hyperostosis of the tuberculum sellae and anterior wall of the sella turcica, with the sella turcica generally not enlarged. Cerebral angiography reveals elevation of the horizontal segment of the anterior cerebral artery, and sometimes a tumor outline formed by microvessels or radial vascular shadows centered on the tuberculum sellae. Therefore, patients with temporal hemianopia, primary optic atrophy, and a normal sella turcica may be diagnosed with tuberculum sellae meningioma.
(4) Third Ventricle Tumors These tumors are more common in children and young adults. They can obstruct the cerebrospinal fluid circulation pathways and compress surrounding structures of the third ventricle, leading to corresponding clinical symptoms. The typical manifestations include increased intracranial pressure, episodic headaches, and impaired consciousness. Tumors growing laterally may compress the optic tract, resulting in reduced vision and visual field defects. The episodic headaches in patients are closely related to body position, with episodes more likely to occur when the patient is lying supine. If the tumor invades the superior colliculus, symptoms such as obesity, drowsiness, or diabetes insipidus may appear. Skull X-ray plain films may show calcification and displacement of the pineal gland. The sella turcica appears normal, with no pathological calcification above the saddle. Ventriculography may reveal filling defects in the third ventricle or only unilateral visualization and enlargement of a lateral ventricle, without displacement. Differentiation from craniopharyngioma is not difficult.
(V) Choroid plexus papilloma of the lateral ventricle Choroid plexus papillomas mostly occur in the trigone of the lateral ventricle. Due to the tumor secreting a large amount of cerebrospinal fluid, communicating hydrocephalus develops. The tumor may float within the ventricle, obstructing the cerebrospinal fluid circulation pathway and causing sudden intracranial pressure elevation. Patients present with severe headache accompanied by nausea, vomiting, and even vertigo or unconsciousness. As a result, patients often assume a forced head position. Compression of surrounding tissues by the tumor frequently leads to hemiplegia, hemisensory disturbances, homonymous hemianopia, and sometimes hearing changes or cerebellar signs. Ventriculography reveals enlargement or displacement of the lateral ventricle, or filling defects. Occasionally, calcification shadows may be seen in the trigone of the lateral ventricle. Lumbar puncture shows increased pressure, and the cerebrospinal fluid contains protein.
(VI) Chondroma of the sellar region Intracranial chondromas commonly arise outside the dura mater at the skull base, generally believed to originate from embryonic remnants of cartilage cells outside the cranial sutures. Patients with sellar chondromas usually do not exhibit increased intracranial pressure. Clinically, they often present with proptosis, orbital pain, oculomotor nerve palsy, visual impairment, and visual field defects. Fundus examination reveals primary optic nerve atrophy. Skull radiographs often show calcification shadows above the sella. Cerebral angiography demonstrates displacement and deformation of the internal carotid siphon. Pituitary symptoms are rare in this condition.
(VII) Ectopic pinealoma of the sellar region Ectopic pinealomas in the sellar region are mostly gliomas, frequently occurring in children and young adults. The initial symptom in most patients is diabetes insipidus, manifested as polydipsia and polyuria, with daily urine output ranging from 3000 to 5000 ml, or even up to 10,000 ml. Subsequently, visual impairment and visual field defects (often bitemporal hemianopia) gradually appear, such as monocular blindness with contralateral temporal hemianopia or homonymous hemianopia. Fundus examination shows primary optic disc atrophy. Patients may exhibit hypopituitarism, decreased libido, and short stature if the disease occurs in childhood. Some may present with precocious puberty. A few patients experience fever or respiratory changes. Headache is mostly localized to the frontal region, with over half of cases accompanied by nausea and vomiting. Some patients may develop dysfunction of the III or VI cranial nerves. Skull radiographs show a normal sella turcica, usually without calcification above it. Angiography reveals signs of a suprasellar space-occupying lesion.
(VIII) Epidermoid cyst of the sellar region Intracranial epidermoid cysts develop from remnants of ectodermal skin tissue during the embryonic period. The sellar region is one of the common sites. Suprasellar epidermoid cysts compress the optic fibers, leading to visual deterioration and visual field defects, with primary optic nerve atrophy. Plain radiographs show an enlarged sella turcica and bone resorption in the superior orbital fissure, optic foramen, and anterior clinoid process. Epidermoid cysts located beside the sella may sometimes involve the trigeminal nerve, causing trigeminal neuralgia. Microscopically, the outer layer of the epidermoid cyst consists of connective tissue, while the inner wall is lined with stratified squamous epithelium and layers of shed keratin, distinguishing it from craniopharyngioma.
(IX) Empty sella syndrome Empty sella syndrome refers to an enlarged diaphragmatic foramen or absence of the sellar diaphragm, leaving the sella turcica empty and filled with cerebrospinal fluid, while the pituitary gland atrophies and is displaced to one side. It is classified into primary and secondary types. The primary type has no obvious intracranial cause and may result from a congenital wide diaphragmatic foramen or absence of the sellar diaphragm, allowing the arachnoid membrane to herniate into the sella, occupying most of it and compressing the pituitary gland to one side. Clinically, it manifests as headache, pituitary dysfunction, and visual impairment, with some patients developing visual field defects. Pneumoencephalography reveals an enlarged sella turcica. Secondary empty sella syndrome may occur after surgical resection or radiotherapy of pituitary tumors or due to pituitary necrosis from other causes. Its clinical manifestations are similar to the primary type, but visual disturbances are more prominent. Occasionally, pituitary tumors may coexist with empty sella syndrome. Pneumoencephalography shows gas filling the sella cavity, accompanied by endocrine disturbances. During surgery, an abnormally wide diaphragmatic foramen may be observed.
(10) Temporal Lobe Tumors Temporal lobe tumors are more common in young adults, with meningiomas and gliomas being the most frequent types. Clinically, they primarily manifest as visual field changes, sensory aphasia, and epileptic seizures. Due to compression or damage to the optic radiation or optic tract, temporal lobe tumors can cause homonymous upper quadrantanopia or homonymous hemianopia. The posterior part of the middle temporal gyrus is the sensory language center; damage to this area often results in sensory aphasia, where the patient can speak but frequently makes errors and cannot comprehend the meaning of others' speech. Some patients may exhibit anomic aphasia. Before epileptic seizures, various hallucinations, such as visual or auditory hallucinations, often occur. When the tumor compresses the internal capsule or cerebral peduncle, hemiplegia may develop. Some patients may experience ataxia or symptoms like athetosis. Cerebral angiography reveals: for tumors in the anterior temporal lobe, the anteroposterior view shows a "V"-shaped image formed by the anterior cerebral artery and middle cerebral artery. In the lateral view, the middle cerebral artery is displaced upward and forward. For tumors in the posterior temporal lobe, the anterior cerebral artery shows mild contralateral displacement, but a "U"-shaped image is often observed, formed by the horizontal segment, sylvian segment, and supraclinoid segment of the anterior cerebral artery and middle cerebral artery.
(11) Occipital Lobe Tumors In cases of occipital lobe tumors, the main clinical manifestations are visual impairment and visual field defects. These present as contralateral hemianopia or quadrantanopia, along with visual agnosia and visual hallucinations. The hallucinations are often unformed, such as flashes of light, sparks, or circles, and may appear to float up and down. Hallucinations can also serve as an aura for epilepsy. There is a head-eye rotation center at the parieto-occipital junction; when this area is affected, the head and eyes turn toward the side opposite the lesion, which helps differentiate it from craniopharyngioma.
(12) Sphenoid Ridge Meningioma The meningioma that needs to be differentiated from craniopharyngioma is the one occurring in the inner third of the sphenoid ridge. The sphenoid ridge is a common site for meningiomas, with the inner third accounting for about 25% of cases. Clinically, it manifests as visual field defects, impaired eye movement, pupil dilation, sluggish light reflex, and ptosis, resulting from compression of the oculomotor nerve, optic nerve, and superior orbital fissure. Additionally, patients often experience anosmia, and a few may develop contralateral limb hemiparesis. Fundus examination may reveal primary optic atrophy on the affected side and contralateral optic disc edema. Skull radiographs show decreased bone density in the orbital wall on the affected side, enlargement and blurred contours of the superior orbital fissure, and often a deformed optic canal due to compression. Cerebral angiography demonstrates slight upward and backward displacement of the proximal segment of the middle cerebral artery, upward and backward displacement of the intracranial extradural segment of the internal carotid artery, and opening of the carotid siphon.
