| disease | Congenital Tumor |
| alias | Congenital Tumors |
Congenital tumors can be classified into craniopharyngiomas, epidermoid tumors, and germ cell tumors, with craniopharyngiomas being the most common congenital intracranial tumors. Depending on the tumor's location and histological characteristics, they have been given various names, such as suprasellar cysts, epitheliomas, epithelial cysts, squamous epitheliomas, adamantinomas, and pituitary adamantinomas. Epidermoid and dermoid tumors (dermoid cysts) originate from residual embryonic epithelial blastomas within the skull. Epidermoid tumors contain only ectodermal components, while dermoid tumors include both ectodermal and mesodermal components, and teratomas contain all three germ layers. Dermoid tumors and teratomas are rare. Germ cell tumors, also known as atypical teratomas, were previously commonly referred to as pinealomas. These tumors arise from embryonic cells rather than the parenchymal cells of the pineal gland.
bubble_chart Epidemiology
Craniopharyngioma is a relatively common intracranial tumor, accounting for 5.1% to 6.5% of intracranial tumors. Among congenital tumors, it constitutes about 60%, and approximately 30% of sellar region tumors, ranking first in children's sellar region tumors and second only to pituitary adenomas in adults. It is more common in males, with a male-to-female ratio of about 2:1. It can occur at any age but is most frequently seen in youth and children, with about 55% of cases occurring between 5 and 20 years old, and over 80% under the age of 40.
Epidermoid tumors, also known as epidermoid cysts, sebaceous cysts, or pearl tumors, account for 1.2% to 2.9% of intracranial tumors, with males slightly outnumbering females. They are most commonly found in young adults. Although these tumors are congenital, due to their slow growth, symptoms usually appear in adulthood.
bubble_chart Clinical Manifestations
(1) Craniopharyngioma is a relatively common intracranial tumor, accounting for 5.1% to 6.5% of intracranial tumors. Among congenital tumors, it constitutes about 60%, approximately 30% of sellar region tumors, ranking first in sellar region tumors in children and second only to pituitary adenomas in adults. It is more common in males, with a male-to-female ratio of about 2:1. It can occur at any age but is most prevalent in adolescents and children, with about 55% of cases occurring between 5 and 20 years old, and over 80% under the age of 40.
(2) Epidermoid tumors: Symptoms generally develop slowly, with the time from symptom onset to medical consultation ranging up to several decades, averaging about 5 years. The symptoms and signs of tumors in various locations are described as follows:
(1) Cerebellopontine angle tumors: Two-thirds of cases present with trigeminal neuralgia as the initial symptom. Advanced stages often manifest as cerebellopontine angle syndrome.
(2) Middle cranial fossa tumors: Mainly characterized by symptoms of trigeminal nerve damage, commonly including facial hypoesthesia and atrophy or weakness of the masticatory muscles.
(3) Intraparenchymal tumors: Symptoms correspond to the tumor's location. Tumors in the cerebral hemispheres often present with seizures, psychiatric symptoms, and mild hemiparesis, while cerebellar tumors typically exhibit cerebellar symptoms such as ataxia. Occasionally, a subcutaneous sinus may also be observed in the occipital region.
(5) Sellar region tumors: Early stages mainly manifest as slowly progressive visual impairment, which may lead to optic nerve atrophy over time.
(6) Extradural tumors: Most originate from the diploë of the skull, and outward growth may present as a subcutaneous mass. As the tumor enlarges, it can cause increased intracranial pressure, often without localized signs.
(3) Germ cell tumors: The disease course is generally short, ranging from 10 days to 2 years from onset to consultation, averaging 7 to 8 months. Main manifestations include symptoms of increased intracranial pressure, local symptoms, and endocrine symptoms. Due to the tumor's tendency to obstruct the aqueduct, hydrocephalus may develop, leading to headache, vomiting, papilledema, and other signs of increased intracranial pressure. Headache is initially paroxysmal, primarily in the frontotemporal region, and progressively worsens.
Tumors located in the pineal region often compress the midbrain tectum, particularly the superior colliculus, causing upward gaze impairment, with a minority also experiencing downward gaze impairment, as well as sluggish or absent pupillary light reflexes. Compression of the inferior colliculus and medial geniculate body may result in tinnitus and bilateral hearing loss. When the tumor extends through the tentorial incisura to compress the superior cerebellar vermis and brachium conjunctivum, ataxia and ocular tremor may occur. Tumors in the suprasellar region may compress the optic chiasm and optic nerves, leading to hemianopia, primary optic atrophy, and visual impairment.
bubble_chart Auxiliary Examination
(1) Craniopharyngioma:
(1) Endocrine function tests: In patients with hypopituitarism, the basal metabolic rate is decreased, and the glucose tolerance curve often appears flat or shows delayed decline. Measurements of various hormones such as T3, T4, FSH, and LH may all be reduced.
(2) Skull X-ray: Abnormal changes are observed in 80–90% of patients on plain skull films, mainly including: ① calcification in the sellar region, ② changes in the sella turcica; the sella often shows a basin-shaped enlargement, and a few may exhibit spherical enlargement, ③ signs of increased intracranial pressure, seen in approximately 60% of patients.
(3) Cranial CT scan: The tumor outline is visible in the sellar region. The tumor parenchyma mostly appears as slightly high-density or isodense images, calcified tissues appear as high-density images, and cystic cavities appear as low-density. Contrast-enhanced scans generally show varying degrees of increased density in the parenchyma. The presence of calcification, cystic cavities, and contrast enhancement can usually confirm the diagnosis.
(2) Epidermoid cyst:
(1) Skull X-ray: Often shows signs of increased intracranial pressure.
(2) Cranial CT scan: Appears as a low-density image, generally without enhancement after contrast injection, though some may show slight edge enhancement.
(3) Germinoma:
(1) Plain skull X-ray: Generally shows signs of increased intracranial pressure. Approximately 40% exhibit abnormal calcification of the pineal gland. Calcification in children or calcification exceeding 1 cm in adults is considered pathological.
(2) CT scan: Mostly shows high-density images, though isodense images may also occur. Calcification is common, with enlargement of both lateral ventricles. Image enhancement is observed after contrast injection.
Diagnosis of epidermoid tumor: For younger patients with slow-progressing intracranial space-occupying lesions presenting multiple but mild signs, this condition should be considered. Most young patients with trigeminal neuralgia symptoms are caused by this disease.
bubble_chart Treatment Measures
(1) Craniopharyngioma: (1) Surgical treatment: This is the primary treatment method. However, due to the tumor's deep location at the base of the brain and its close connection with surrounding structures, surgical resection is difficult and carries significant risks. The surgery typically involves a right frontal skin-bone flap, and total resection is performed via the frontal base approach, preferably under a microscope. During the operation, traction on the hypothalamus should be minimized as much as possible. Care must be taken to avoid injury to nerves and blood vessels, and the tumor should be meticulously dissected and removed. Corticosteroid therapy, preferably dexamethasone, should be administered before, during, and after the surgery, with gradual tapering starting 4–5 days postoperatively.
(2) Radiotherapy: Radiation can reduce cystic fluid formation. It is generally recommended for patients who have undergone partial resection, with doses of 7000 cGy for adults and 5500 cGy for children.
For cystic tumors without significant optic nerve compression, puncture and aspiration of the cystic fluid followed by injection of an appropriate amount of radioisotope for internal radiotherapy can also yield good results.
(2) Epidermoid tumor: Surgical resection of the tumor is recommended, with the principle of complete removal of the tumor capsule to prevent recurrence. The main postoperative complication is aseptic meningitis, but recovery is generally good. A small number of patients may experience recurrence years or even decades later.
(3) Germinoma: Small tumors may be treated with radiotherapy, while larger tumors may undergo shunt surgery followed by radiotherapy. The radiation field should ideally include the spinal canal. These tumors are highly sensitive to radiotherapy, and the treatment outcomes are satisfactory.
