Giant cell tumor of bone (GCT) is a benign aggressive tumor of bone primary, accounting for 20% of primary bone tumors, which was earlier classified in low grade malignancy, then into intermediate (between benign and malignant) and now classified as benign aggressive tumor (stage 3). It can be seen that the biological behavior of giant cell tumor of bone is complex and variable. The etiology of giant cell tumor of bone is unknown.
Clinical presentation
Age: 20-40 years old is the best age of onset, accounting for about 80% of cases.
Sex: There is no gender difference.
Location: The most frequent sites are the lower femur and upper tibia (around the knee joint), followed by the proximal humerus and distal radius, and other sites are the vertebrae, sacrum, ilium, proximal fibula, distal tibia, etc.
Symptoms: The main manifestation is localized pain, which gradually worsens, and as the condition progresses, there may be swelling and pressure pain. If a fracture occurs, it is characterized by sudden and severe pain, swelling, deformity, and inability to move. Fracture triggers are often minor trauma. There are no systemic manifestations such as fever and wasting.
Diagnosis and Differentiation
Auxiliary examination
1.Imaging examination
X-ray plain film: It is the most basic examination, showing osteolytic destruction of bone end, eccentric, may have expansion, no calcification and osteogenesis.
CT: To do enhanced CT, which can look at the boundary and scope of tumor, and the blood flow of tumor.
MRI: It can better show the boundary of the tumor, but cannot replace CT.
ECT: Giant cell tumor of bone has multiple possibilities in individual cases, and whole body bone scan can exclude multiple foci.
Chest CT: Giant cell tumor of bone has the possibility of lung metastasis, and chest CT is needed.
2.Laboratory examination
There are no specific indicators for giant cell tumor of bone.
3.Pathological examination
Histological examination includes what is seen by the naked eye, what is seen under the microscope, immunohistochemistry and molecular biology of the large specimen. The most basic one is HE section. Giant cell tumor of bone is mainly composed of giant cells and spindle cells, which used to be classified into three levels (Jaffe classification).
Disease diagnosis
The combination of clinical, imaging, and pathology should be used with extra caution, especially if there is a discrepancy between these three.
Differential Diagnosis
Giant cell tumors of bone often need to be differentiated from
1. Aneurysmal bone cysts: They are usually found in adolescents and are often combined with other tumors, such as giant cell tumor of bone combined with aneurysmal bone cysts, chondroblastoma combined with aneurysmal bone cysts, etc. The best site for a single aneurysmal bone cyst is the spinal appendage, and the imaging performance of those located in the limbs is not easily distinguished from giant cell tumor of bone.
2. Osteosarcoma: It occurs in adolescents, and the common site is the long bone epiphysis, with short course and heavy symptoms. The pathology shows direct osteogenesis of malignant tumor cells.
3. Bone cyst: adolescents are more common, often located in the proximal humerus and proximal femur, mostly with fracture as the first symptom, and the X-ray shows central and swelling changes with clear borders and no enhancement on CT.
Disease treatment
Surgical treatment
Surgery for giant cell tumor of bone is the preferred treatment option. The surgical boundary of benign aggressive tumor requires to achieve marginal resection, which means that the implementation of complete resection of tumor bone outside the tumor is required, which inevitably causes certain functional disorders, and since patients with giant cell tumor of bone are relatively young, they hope to have a long-term good function. However, the recurrence rate of simple curettage to preserve function is 40-60%. Therefore, the concept of expanded curettage is proposed: the core concept is that although curettage is done, the surgical border of the margin is finally reached through a series of means, so that both long-term good function is preserved and a satisfactory surgical border is achieved, and the recurrence rate can be reduced to about 10%.
Extended curettage, instead of simply scraping and superimposing other physicochemical methods, is based on a profound understanding of the characteristics of the tumor, followed by abrasive drill grinding, argon knife cautery, carbolic acid coating of the bone shell, liquid nitrogen freezing, high-pressure rinse gun flushing, and so on. The indications for these methods must be individualized and never a simple 1+1=2.
After scraping and filling with bone cement, it is believed that the high temperature generated during the polymerization of bone cement can kill the residual tumor cells and thus can reduce
In this case, only amputation of the tumor segment can be performed.
The recurrence rate is low, but some scholars deny this idea. Bone grafting near the articular surface can protect the articular cartilage and reduce the occurrence of osteoarthritis, and filling the rest of the cavity with bone cement is beneficial for postoperative follow-up to determine whether there is recurrence, because if all bone grafting is done, bone graft resorption and tumor recurrence cannot be easily identified.
Not all tumors are eligible for resection, and some of them can only be resected and replaced by artificial prosthesis. Since the artificial prosthesis will cause some functional impairment and has a long life span, it should be carefully selected. In the case below, the tibia is swollen and there is no complete bone shell, so there is no scraping condition, so we can only perform resection of the tumor segment.
Postoperative precautions: 1.
1. Functional exercise.
Whether after scraping or artificial prosthesis replacement, good function can only be achieved with proper functional exercise. The specific exercise program depends on the surgical method, tumor site and intraoperative bone condition. Therefore, patients should carry out functional exercises in full accordance with the instructions of the surgeon.
2. Review.
Even after resection there is still a certain recurrence rate, so it is necessary to review regularly and monitor the local. Although giant cell tumor of bone is benign, it still has more than 3% metastasis rate, and the main site of metastasis is lung, but there are also very few multiple cases, so systemic monitoring is also necessary.
The review includes: local X-ray plain film, CT, ultrasound, whole body bone scan, and chest CT.
The time of review: every 3 months within 2 years after surgery; every 6 months between 2 and 5 years; and every year after 5 years. The content of each review will be decided on a case-by-case basis, and not all tests will be done once.
In addition, there are cases of recurrence and malignancy after more than ten years, so the follow-up of giant cell tumor of bone should be lifelong.
3. Diet: No special requirements.
Chemotherapy
Generally no chemotherapy. Chemotherapy can be used for malignant giant cell tumor of bone or extensive metastasis, but there is no recommended chemotherapy regimen to use.
Radiotherapy
Radiotherapy is generally not used. This is because radiotherapy can cause sarcomatous transformation. For those recurrent, inoperable, or giant cell tumors of bone in the spine or sacrum, which are difficult to achieve expanded scraping by surgery, adjuvant radiotherapy can be used.
Other treatments
In recent years diphosphonates have been used for the adjuvant treatment of giant cell tumor of bone with some efficacy. [1-3]
Disease prognosis
The majority of patients with giant cell tumor of bone can be cured with timely and regular treatment. The recurrence rate is less than 10% after enlarged curettage, and reoperation is possible after recurrence. There are 3-6% of patients with metastases, which are difficult to treat and are currently facing a difficult problem.