In the last series, we opened a chapter to introduce the relatively rare intraspinal tumor , and introduced lipoma in detail. So today, we will introduce another rare tumor- teratoma , which is also a type of congenital tumor in the spinal canal.
teratoma , many people will guess when they hear this name: Is it a malformed fetal tumor? In fact, teratomas are not formed from fertilized eggs, so they have nothing to do with pregnancy or fetus. At present, most people believe that teratomas in the spinal canal originate from ectopic primordial germ cells. These cells have the potential ability to differentiate into various tissues of the body, so teratomas contain three germ layers: inner, middle and outer. The tissues of , including lipids, epithelial components, bone, cartilage, hair, fat, muscle tissue and nervous tissue, are similar to normal tissues of the human body, but are arranged in a disordered structure, a bit like a "fetus" or "teratoma" with developmental abnormalities. This is where the name "tumor" comes from.
The incidence of intraspinal teratoma is low, accounting for 2.8% of primary tumors in the spinal canal in domestic reports and 0.15% in foreign countries. Intraspinal teratomas are more common in children and adolescents and can be located in any segment of the spinal canal, but are more common in the thoracic and lumbar segments. It is most commonly located under the extramedullary dura mater, followed by the intramedullary spinal cord, with the conus medullaris being the most common site. Nearly half of patients with intraspinal teratomas may be combined with other malformations, such as diastematomyelia, tethered spinal cord, skin changes (hairy rashes, small nodules), etc.
- Teratomas are divided into cystic and solid according to their general structure;
- are divided into benign and malignant according to their biological characteristics;
- are divided into mature, immature and malignant teratomas according to the degree of tissue differentiation.
The mature type is a benign tumor composed of well-differentiated tumor tissue ; the immature type of tumor tissue is poorly differentiated and is mainly composed of immature tissues, such as immature nerve tissue and immature cartilage. Malignant transformation of teratoma refers to the malignant transformation of a certain germ layer of tissue in the tumor tissue, such as canceration of epithelial tissue , and sarcoma transformation of mesenchymal tissue .
Most benign teratomas are cystic, and the mass contains fat, hair, teeth, and fluids. Some cysts have solid areas in their walls, called cephalic knots. The cephalic knots are composed of bone, cartilage, fat, etc. .
Malignant teratomas are mostly solid and contain some differentiated mature tissues as well as some immature embryonic tissues. These immature tissues are malignant components. Like other malignant tumors, malignant teratomas grow quickly and are more harmful to the human body. They can also cause bleeding, necrosis and metastasis.
Movement disorders and pain are the most common symptoms in patients with intraspinal teratomas, and bladder and rectal dysfunction are also common. patients usually present with pain, numbness, weakness or difficulty urinating in the lumbosacral region, and lower limbs as their first symptoms. Some patients also seek treatment for a rash with long hair on their back. As the disease progresses, paraplegia, urinary and fecal incontinence, etc. may occur in the later stages.
Intraspinal teratomas are oval, fusiform or irregular in shape, and their borders are usually clear. The mass on CT showed mixed density, with low density showing adipose tissue, medium density showing soft tissue, and high density showing calcification. Large tumors can also show enlargement of the spinal canal and widening of the vertebral pedicles. On MRI, it appears as a cystic-solid mass with clear boundaries and mixed signals; the solid part is obviously enhanced, and the cystic part generally has no enhancement or the edge of the lesion is enhanced. The diagnosis can be made clearly when the mass exhibits short T1, short T2, suppression sequence hypointense, and calcification hypointense of fatty component. MRI can also accurately locate tumors, understand tumor morphology and its relationship with the spinal cord, provide precise anatomical relationships for surgical treatment, and reduce surgical risks.
Microsurgical resection is the treatment of choice for intraspinal teratomas. Surgical resection can not only reduce the tumor volume and relieve spinal cord compression, but also clarify the nature of the tumor, providing a basis for further treatment and prognosis judgment. During the operation, the tumor should be removed as much as possible to relieve spinal cord compression and reduce the postoperative recurrence rate. However, due to the complex structure of teratomas, their long growth time, and their close adhesion to the spinal cord and nerves, in order to avoid spinal cord damage , the tightly adherent capsule, fat, and calcified tissue should not be completely removed.Intraoperative nerve electrophysiological monitoring can help determine the spinal nerve and tumor capsule, which is helpful to improve the degree of tumor resection.
Benign teratomas, especially those with intact tumor capsule, do not require radiotherapy or chemotherapy after total surgical resection, and their prognosis is good. Malignant teratomas are sensitive to radiotherapy and chemotherapy. Early postoperative radiotherapy and chemotherapy can significantly reduce tumor recurrence and metastasis and improve the patient's survival rate.
Typical case
1. A middle-aged male with chronic onset and chronic course;
2. Five years ago, he had symptoms of frequent urination and urgency of urination without obvious triggers. He went to the urology department for treatment, urinary tract infection was ruled out, and no special treatment was given. The above symptoms have worsened in the past six months, and difficulty in urinating has occurred. He had an indwelling urinary catheter three times due to urinary retention. I have been going to the urology department and no cause has been found. In the past three months, I started to have weakness in my left lower limb, so I went to a local hospital for a lumbar spinal magnetic resonance examination, and it was found that there was a space occupying the spinal canal at the L3 level;
3. Physical examination: She was clear and sharp, the muscle strength of both upper limbs and muscle tension were normal, and the left lower limb was normal. The muscle strength of the lower limbs was grade 4, and the muscle strength of the right lower limb was normal. My whole body feels normal. The cremasteric reflex is weakened. Pathological signs were negative. Unsteady walking gait;
4. Urodynamic test: neurogenic bladder;
5. MRI examination: L3 level extramedullary subdural oval mass with clear boundary and mixed signal; (see Figure 1)
6. Surgery Medium situation: L3 level teratoma was seen during the operation, containing sebaceous secretions, hair, cartilage, fat and other components. The fat components of the tumor are adherent to peripheral nerves. First, the cutin, hair and other components in the tumor are removed, then the fat components are sharply separated from the nerves, and finally the tumor capsule is removed. The filum terminale was distinguished and then cut off;
7. Postoperative MRI: tumor resection was satisfactory; (see Figure 2)
Figure 2 Postoperative MRI review showed that tumor resection was satisfactory
8. Postoperative pathology: mature teratoma;
9. Postoperative recovery: The muscle strength of the left lower limb returned to normal 2 weeks after the operation. Urinary function improved significantly, with slight effort, and residual urine volume was less than 20ml. No tumor recurrence was found during 1-year follow-up.
