What Is a Chordoma?

Pathological typing:

Zhang Qiuhang	(Chief physician)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University
Guo Hongchuan	(Deputy Chief Physician)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University

Chordoma originates from the residual chordoma tissue of the embryo. During the embryonic period, the upper end of the spinal cord is distributed on the sphenoid bone and occipital bone of the skull base, partly reaching the cranial surface, and connecting with the dura mater above the sphenoidal saddle. The occipital portion can reach below the bone (ie, the pharyngeal surface), and a part Can be located between the skull base and the pharyngeal wall. The lower end of the chordal cord is distributed in the middle and lateral side of the zygomatic tail. Therefore, chordomas are more common in these areas, especially the skull base occipital and palatal tail, which are the most common.

Western Medicine Name: Chordoma
Affiliated Department: Surgery-Neurosurgery

The main symptoms: headache
Contagious: Non-contagious

Classification of chordoma disease

Pathological typing:

Chordoma common type

Also known as the typical type, the most common, accounting for 80% to 85% of the total. There is no cartilage or other mesenchymal components in the tumor. More common in patients 40 to 50 years old, less than 20 years old. No gender differences. There are several growth ways in pathology, but the flaky growth is characterized by vacuole-like epithelial cells and a mucus matrix. Cytokeratin and epithelial membrane antigen were positive for immunostaining. Electron microscopy showed nucleoli. These features help distinguish this disease from chondrosarcoma, which is immunostaining negative and electron microscope-free.

Chordoma chondroma

It accounts for 5% to 15% of chordomas. Its microscopic features include, in addition to the typical see above, how many different hyaline cartilage-like areas. Although some authors classified it as low-grade malignant chondrosarcoma after observation by electron microscope, a large number of immunohistochemical studies have found that the epithelial marker antigen of chondroid chordoma is positive. The onset age of this type is relatively young. In the past, the prognosis was generally better than that of the common type, and now the prognosis of the two is similar.

Chordoma interstitial

It is also called atypical type, accounting for 10% of chordoma. It contains common type components and malignant mesenchymal components. Microscopically, it shows active tumor proliferation, significantly reduced mucus content and visible mitotic figures. A small number of tumors can be metastasized by blood flow and implanted in the subarachnoid space. This type can be secondary to malignant changes after common type radiotherapy. Death usually occurs 6 to 12 months after diagnosis. ^[1]

Causes of chordoma

When the fetus develops to 3 months, the spinal cord begins to degenerate and disappear, leaving only in the disc, the so-called nucleus pulposus. If the chordal embryo remains in the above-mentioned area and remains after birth, it can gradually develop into a tumor.

Chordoma Pathogenesis

The research on the pathogenesis of chordoma is still in the exploratory stage. In recent years, with the construction of human DNA sequence maps, the analysis of DNA molecules can be used to identify the loss or amplification of specific genomic regions. The chromosome deletions and mutations of chordomas currently reported are mainly at lq36 and 7q33.

Chordoma pathophysiology

It can be seen under microscope that a typical chordoma is composed of epithelioid cells. The cell body is large and polygonal. Because the cytoplasm contains a large number of vacuoles, which can be stained with mucus, it is called vesicle cells or vacuole cells. Cytoplasmic vacuoles sometimes merge and push the nucleus aside, so they are also called "signet ring cells." In some places, the boundaries of the cells disappear, forming a myxoid complex. The formation of a large number of vacuole cells and mucus is a pathological feature of the disease. ^[2]

Clinical manifestations of chordoma

Intracranial chordoma is a benign tumor with slow growth and long duration. Headache is the most common symptom in more than 3 years. About 70% of patients have headaches. Sometimes they have headaches for several years before going to the doctor, and they are often full headache , Can also be extended to the back of the pillow or neck. The nature of the headache was persistent dull pain with no significant change throughout the day. If the intracranial pressure is increased, it will inevitably increase. The headache of chordoma is related to the slow and persistent skull base infiltration, and the headache can recur.

The clinical manifestations of intracranial chordoma can vary depending on the tumor site and tumor development direction.

Hypophysis of saddle chordoma is mainly manifested in impotence, amenorrhea, and weight gain. Optic nerve compression produces primary optic nerve atrophy, vision loss, and bilateral temporal blindness.

Parachoral chordomas are mainly manifested in , , and cerebral palsy. Among them, abductor involvement is more common. This may be because the abductor is too long. In addition, the proximal end of the abductor is often the origin of the tumor. As a result, its incidence is high. Generally, the progress is potentially slow, even after 1 to 2 years. Cerebral palsy can be bilateral, but often unilateral, and it is often difficult to understand the left side.

The chordoma of the slope is mainly manifested as symptoms of compression of the brainstem, that is, walking disorder, pyramidal tract sign VI, and sacral neurological disorder. Among them, bilateral abductor nerve damage is its characteristic.

Extensive type: The range of lesions is wide, exceeding one of the above types, and even extending to the skull base displacement area, according to the clinical symptoms and imaging findings of the above related types.

complications:

Because the tumor occurs at the base of the skull, it can cause traffic hydrocephalus. If the tumor develops toward the cerebellopontine angle, hearing impairment, tinnitus and dizziness occur. Chordoma originates near the wall of the nasopharynx, often protruding into the nasopharynx or infiltrating one or more paranasal sinuses. Causes nasal inability to ventilate, obstruct, and pain, often with purulent or bloody nasal secretions, but also due to mechanical obstruction and difficulty in swallowing. Nasopharyngeal symptoms often appear before nerve involvement. Remember to check the nasopharyngeal cavity for 13% ~ 33 % Chance to see a lump.

Chordoma diagnosis and differential diagnosis

Adult patients with a long history of headache and lateral abdomen palsy should consider the possibility of chordoma but the diagnosis must be confirmed by X-ray, CT and MRI imaging.

Chordoma should be distinguished from meningioma. Meningiomas in the same area can cause localized osteoporosis and thinning or osteogenesis, with few osteolytic changes. DSA usually thickens the meningeal arteries and has obvious tumor staining.

For example, the growth of chordoma into the posterior cranial fossa should be distinguished from the acoustic neuroma of the pontine cerebellum. Acoustic neuroma is mainly manifested by enlargement of the inner auditory canal and absorption of petrosal crest on plain radiographs and CT of the skull. MRI often helps with differential diagnosis.

Chordoma in the saddle area needs to be distinguished from pituitary adenoma and craniopharyngioma. Most of the latter two do not cause extensive bone destruction at the skull base, and pituitary tumors generally show enlarged saddle involvement, deepening of the saddle floor, and bone resorption. On CT of craniopharyngioma, arc-shaped or eggshell-like calcification of the cystic wall can be seen, which usually does not cause damage to adjacent bones, and the brain nerve damage of the two is mostly limited to the optic nerve, while chordomas are mostly manifested as abductor disorders. Multicranial nerve damage, radiological findings of bone osteolytic changes in the skull base and intra-tumor plaques or flaky calcifications.

Chordoma that grows down into the nasopharynx is similar to nasopharyngeal carcinoma metastasized to the skull base because of its clinical manifestations and X-ray examination characteristics. The differential diagnosis is mainly based on a nasopharyngeal biopsy.

Chordoma and chondrosarcoma of the para Saddle type or long middle cranial base are difficult to distinguish. Immunohistochemical staining is very helpful. Chordoma is positive for a variety of tissue markers, such as: Cyto-K6 / 7 EMA7 / 7, CEA6 / 7, GFAP0 / 7, Des0 / 7, -AT7 / 7, Lyso4 / 7 and chondrosarcoma were all negative.

Chordoma treatment

Chordoma surgery

There is a deep anatomic location of chordoma, surgical exposure is difficult, and the onset of disease is hidden. The course of disease is long. When the patient comes to the clinic, the tumor has extensively invaded the skull base, so the operation is difficult. Because chordoma is not sensitive to radiation, conventional radiotherapy usually only plays a palliative role, and the long-term efficacy of radiosurgery is still unclear. Therefore, endoscopic nasal and / or oral approaches to skull base surgery are still The main treatment for this disease.

Chordoma conventional radiotherapy

It is an adjunct to surgical treatment.

Chordoma radiosurgery

Including -knife, proton knife and X-knife. In particular, proton knives can be used for large-dose segmentation treatment, which combines the advantages of radiosurgery and conventional radiotherapy, showing safety and effectiveness, and is suitable for residual tumors in important areas of neurovascular after surgery.

Chordoma other treatments

Including hyperthermia, 90Y local burial therapy and chemotherapy, but the effect is not certain.

Chordoma drug treatment

Chemotherapy drugs have always been considered to have no obvious therapeutic effect on chordoma: in recent years, there have been reports in the literature that targeted drugs have been used in the treatment of chordoma. Targeted therapy for chordoma may have good therapeutic prospects. ^[3]

Chordoma Prognosis

Skull base chordoma is a rare bone tumor. It is a benign tumor in histology, but has the following malignant characteristics: deep location, easy to invade the brain and important nerve blood vessels; invasive growth, most without obvious capsules; Metastasis can occur; it is not easy to completely resect, and the recurrence is close to 100%; more patients die than a few years after diagnosis. Therefore, once a skull base chordoma is diagnosed, it should be treated as a malignant tumor.

In the early reports at home and abroad, the survival rate of cranial chordoma is generally low, and the 5-year survival rate is maintained at 30% to 40%. In recent years, relevant reports at home and abroad have gradually increased. The postoperative survival rate of spinal cord chordoma has improved significantly, and the 5-year survival rate has remained at 60% to 70%.