Chordoma is a rare congenital tumor that originates from the remnants of embryonic chordal structures and occurs mostly along the neuraxial sites, mostly at the junction of the pterygoid and occipital bones such as the slope and saddle area if located intracranially, and in the spine, mostly at the sacrococcygeal region, followed by the cervical, thoracic and lumbar spine. Most chordomas are benign, but a few are malignant and have an infiltrative growth pattern.
Clinical manifestations of chordoma
(1) Long duration of disease, early symptoms are mainly headache, and symptoms of increased intracranial pressure are less common.
(2) Symptoms of saddle area compression: decreased visual acuity, visual field defects, primary optic nerve atrophy, hypopituitarism, hypothalamic involvement manifestations such as obesity, polydipsia, drowsiness.
(3) Symptoms of paracranial cranial fossa involvement: ipsilateral Ⅲ to Ⅺ cerebral nerve damage symptoms, among which symptoms of damage to the articulatory nerve, abducens nerve and optic nerve are more common, a few have cone bundle signs; protrusion into the orbit may have eye protrusion, blindness and eye muscle paralysis.
(4) Symptoms of brainstem and cerebellar involvement: bilateral lower extremity cone bundle signs and nystagmus, ataxia.
(5) cerebellopontocerebellar horn syndrome: tumor development to the upper part of the brain, manifesting as hearing impairment, tinnitus and vertigo.
(6) Posterior group of cerebral nerve symptoms: tumor develops outward and downward, manifesting as dysphagia, choking, hoarseness, etc.
(7) Symptoms of nasopharynx within the tumor invading the pterygoid sinus: the tumor develops toward the nasopharynx, manifesting as nasal non-ventilation, obstruction, pain, bloody or purulent discharge from the nasal cavity, and nasal mass.
(8) Spinal symptoms: corresponding local symptoms of different segments of the spine and symptoms of the involved spinal cord and nerve roots.
Ancillary tests for chordoma
(1) Head X-ray: Bone destruction and tumor calcification foci at the site of tumor, sometimes tumor shadow can be seen in the area of bone defect.
(2) Head CT: round or irregular high-density shadow at the skull base, intra-tumor calcification and cystic changes, hemorrhage, brain stem and fourth ventricle may be displaced by pressure. Bone window image shows bone destruction at the skull base, and most of the tumors have insignificant enhancement or mild enhancement.
(3) Cranial MRI: The signal level is inconsistent, generally low signal on T1-weighted image and high signal on T2-weighted image, and there may be calcification and cystic lesions in the tumor.
(4) Cerebral angiography: Tumors located in the saddle area can be seen with lateral displacement of the siphon of the internal carotid artery and upward elevation of A1 segment. Tumors located in the saddle area can be seen with upward shift of the cavernous sinus segment of the internal carotid artery and upward elevation of M1 and M2. Tumors of the slope are seen with posterior or lateral displacement of the basilar artery. Tumor staining is seen in the venous phase.
Principles of treatment for chordoma
Surgical treatment uses different approaches according to the specific site where the tumor is located, but total resection is difficult due to the deep tumor.
(1) Saddle area type: frontotemporal approach, trans-oral pterygoid sinus approach, trans-inferior nasal septal approach, etc. are used.
(2) Middle cranial fossa type: Trans-temporal inferior epidural approach is used.
(3) Slope type: trans-oral pharyngeal approach is used.
Radiation therapy should be done by general radiotherapy, X-knife or γ-knife, etc. Since the tumor is mainly located at the skull base, attention should be paid to protect the brain stem during radiotherapy.
The prognosis is no recurrence for a long time for those who have undergone total surgical resection, but according to the current treatment method, the proportion of total surgical resection is low, easy to recur, and the tumor has a poor prognosis due to extensive invasion of the skull base.