Chondroblastoma

Introduction to chondroblastoma Chondroblastoma is a benign tumor derived from immature chondrocytes (chondrocytes). It was first discovered by Ernest Codman. The epiphysis, which is mainly located at the end of the long bone, can also be located in the bony, also known as Codman tumor, due to secondary development. The ossification center, also known as benign osteophyte chondroblastoma. The secondary ossification center, which occurs in the long bones, is more common in the humeral head, femoral condyle, and tibial plateau. Sometimes it can be seen in small bones without secondary ossification (such as the humerus) and flat bones (such as the humerus). . It usually occurs in late childhood or adolescence. basic knowledge The proportion of sickness: 0.00001% Susceptible population: It occurs in men, the ratio of male to female is 2 to 3:1, and most cases occur between 10 and 20 years old. Mode of infection: non-infectious Complications: fracture aneurysmal bone cyst

Cause of chondroblastoma

Etiology (30%):

The etiology of chondroblastoma is still not clear. Some scholars believe that chondroblastoma is derived from embryonic cartilage and may be a metamorphosis of cartilage.

Pathogenesis (10%):

The pathogenesis of chondroblastoma is not well understood.

General examination

The chondroblastoma and the surrounding bone cancellous boundaries are clear. The lesions are blue-gray to gray-white, with gravel-like yellow calcifications and necrotic areas. The tumor texture is rubbery, and there may be cystic changes in the lesions, most of which have hemorrhagic changes. Chondrogenic neoplasms can be invaded into the joint by direct or indirect pathways.

2. Microscopy

The histological features of chondroblastoma are: round, oval or polygonal chondrocytes with clear cytoplasmic edges, cytoplasmic eosinophilic staining, nucleus round, oval, kidney-shaped, often 1 to 2 Nuclei, occasionally large cells with deep nuclear staining, but no obvious nuclear abnormalities, no pathological mitosis, multinucleated giant cells can be dispersed in chondrocytes or concentrated in the area of hemorrhage or necrosis. Giant cells are smaller and smaller than those seen in giant cell tumors. In some cases, chondrocytes and multinucleated giant cells can be lined in hemorrhagic lesions and cystic hemorrhage, similar to aneurysmal bone cysts. Microscopically, it is said that there are 15% to 25% of these changes in chondroblastoma.

Lichtenstein emphasized that the histological diversity of chondroblastoma stems from the different stages of the development of the lesion, initially with more cells in the tumor, progressive necrosis, absorption, repair fibrosis, and to cartilage-like and bone tissue. Metaplasia, cell membrane calcification of some tumor cells and even calcification of bone matrix, nuclear disappears to form a special "lattice" is the main point of diagnosis, necrosis is absorbed and replaced by fibrous tissue or cartilage-like tissue, the maturation of cartilage-like tissue can also be The formation of hyaline cartilage, the above various changes, such as hybridization, increases the complexity in pathological diagnosis.

Chondrocyte tumor prevention

The cancer prevention strategy includes a series of interventions that can reduce tumor morbidity and mortality.

Primary prevention refers to interventions in the population to prevent the occurrence of diseases such as youth smoking prevention programs to prevent lung cancer from occurring in the future.

Secondary prevention refers to the identification and treatment of those who have an increased risk of disease but are asymptomatic. Generally, secondary prevention is equivalent to tumor screening. For example, Pap smear is used to detect cervical cancer and precancerous lesions, and screening can detect the risk. A high-sex population and a population that can be detected in an asymptomatic period, a practical screening method must be acceptable to the patient, can accurately detect the disease, and the treatment of the detected disease can make the incidence and The mortality rate is reduced.

Tertiary prevention refers to the treatment of a disease to prevent or reduce comorbidities.

Chemoprevention

Chemoprevention involves the use of natural substances or drugs that prevent or reverse precancerous lesions, inhibiting tumor initiation or inhibiting existing lesions.

Retinoids, including all retinol analogs or vitamin A, have an effect on the differentiation of epithelial cells. The role of retinoids has been studied in animal studies, but is inconsistent with findings in the population.

Tamoxifen and raloxifene, selective estrogen receptor (ER) modulators (SERMs), which have estrogen-like and anti-estrogen-like effects depending on the target tissue, include 13,000 in one A double-blind, randomized trial of tamoxifen and placebo in a healthy high-risk breast cancer woman, tamoxifen, reduced the incidence of invasive breast cancer by 44%, but appeared in participants in the trial Side effects, such as increased risk of endometrial cancer, pulmonary embolism, deep vein thrombosis, stroke and cataract (Fisher et al., 1998), are currently undergoing trials of tamoxifen and raloxifene (STAR) with the aim of Evaluate the effects of these two drugs on breast cancer prevention and closely observe other clinical outcomes such as heart disease, endometrial cancer, osteoporosis, fractures, and cataracts.

Epidemiological studies have shown that the use of NSAIDs can reduce the incidence of colon cancer (Giovannucci et al, 1995; Greenberg and Baron, 1996), randomized controlled studies have shown that vitamin E and selenium may have a role in preventing prostate cancer, and selenium may prevent knots Rectal cancer and lung cancer (Byers, 1999), evidence from animal models suggests that selenium can inhibit prostate cancer (Nakamura et al., 1991). When studying the effects of selenium on skin cancer, it was found that participants had a lower incidence of prostate cancer ( Clark et al., 1996, 1998). In addition, two randomized studies in China have shown that selenium supplementation can reduce the overall mortality rate of cancer and the mortality of gastrointestinal malignancies (Blot et al., 1993a, 1993b). Selenium may play a role in inhibiting the development of human cancer.

In a randomized, double-blind, placebo-controlled trial of vitamin E and vitamin A, the incidence of prostate cancer was reduced by 32% and mortality was reduced by 41% (Heinonen et al., 1998). Vitamin E is reducing lung cancer. It also has a role in cancers of the gastrointestinal tract.

Based on research results on selenium and vitamin E, NCI established the Selenium and Vitamin E Chemoprevention Test Fund (SELECT), which includes 32,000 healthy men for up to 5 years and is designed to be double-blind versus placebo. , 2 × 2 square matrix design.

There are several prospective epidemiological studies evaluating chemopreventive drugs that are underway. The physician's health study began in 1982 with a 2×2 square matrix design, randomly selected 22,000 people to give beta-carrots. Or aspirin or both drugs, the women's health study uses nurses as a research object to study the effects of beta-carotene, aspirin and vitamin E on tumor incidence (Buring and Hennekens, 1992). The study has recently completed the work of recruiting participants and will continue to conduct long-term follow-up observations. Phase II and III clinical trials of several chemotherapy preventive drugs are currently underway, and it is expected that some definitive results will be obtained from them, such as eating certain Special foods or supplements with certain ingredients can prevent or reverse the tumor.

2. Prevention of tumors in healthy people

Epidemiological studies show that about one-third of the 500,000 cancer deaths each year in the US are related to dietary factors, and another one is related to smoking. Therefore, for most non-smoking Americans, diet and Physical exercise is an important regulator of maintaining health and reducing the risk of cancer.

Reduce the risk of cancer, including adequate nutrition, physical exercise, smoking cessation, avoid contact with occupational carcinogens, diet should eat fruits and vegetables every day, properly control foods with high fat content, limit drinking, pay attention to nutrition while also Do aerobic exercise several days a week to avoid getting too fat.

Chondroblastoma is a benign osteophyte chondroblastoma. The recurrence rate of extensive large mass resection is low. The recurrence rate of scraping bone graft is 10%. Early diagnosis and early thorough treatment are the key to reduce the recurrence rate and disability rate.

Chondroblastoma complications Complications, aneurysmal bone cysts

Can be complicated by joint fluid exudation, joint swelling, pathological fractures are rare, "benign" lesions of distant metastasis occasionally occur, sometimes lesions may be associated with aneurysmal bone cysts, infiltration of surrounding soft tissue, tumor tissue invasion of blood vessels and formation of metastasis .

Symptoms of chondroblastoma common symptoms joint fluid effusion exudation trauma slow growth

Chondrogenic chondroma occurs in men, the ratio of male to female is 2 to 3:1, and most cases occur between 10 and 20 years old. Due to its slow growth, the symptoms remain stable after several years of tumor development, so at 25 It can also be seen in the age of 30, but it originated in the bone growth phase. In special cases, it is also seen before the age of 10 and after 20 to 25 years old.

1. Symptoms and signs

There are no special clinical symptoms and signs in this disease. The clinical symptoms are generally intermittent pain, swelling, accompanied by obvious tenderness, symptoms of adjacent intra-articular disorders, exudation of joint fluid, pathological fractures are rare, symptoms appear late and light. Symptoms often exist for several months, sometimes only a few years after the tumor is diagnosed, because the tumor always occurs around the joint, the symptoms are often related to the joint, followed by knee, shoulder, hip joint, chondroblastoma is moderate Pain, which can show tumors due to trauma or compression. In the more swelled and superficial chondroblastoma, the affected bone can be mildly eccentrically swollen, joint function can be limited, and there can be moderate joint effusion. For pulp-blood exudation, the muscles can shrink and the symptoms can last for months to years.

2. Good hair

Chondroblastoma often occurs in the epiphyseal or epiphyseal prominence of long tubular bone, followed by the femur, tibia and tibia. At the proximal end of the femur, the tumor can originate from the epiphysis or large trochanter, and the chondroblasts occur at the proximal end of the humerus. Tumors often originate from the greater tibia of the humerus. In the humerus, it often occurs at the proximal end of the humerus. Most of the chondroblastoma is located around the knee, shoulder and hip joints. The primary is usually in the metaphysis or the backbone. Femur (33) %), tibia (20%) and tibia (18%) are the best sites, the most common in the humerus and humerus are at the proximal end, while the femur is far and the proximal end is the same, the lower limbs are more common than the upper limbs, other long Tubular bones, such as ulnar, humerus, and humerus are rare. The chondroblastoma on the hand and foot bone accounts for about 10%, especially the talus and calcaneus. The rest of the bone is rare. The typical part is located in the joint. On the surrounding bone, adjacent joints appear to resemble the primary synovitis process. About 30% of patients have joint exudate. Due to dilated growth, chondroblastoma tends to destroy the growth of cartilage, which can spread from the epiphysis to the adjacent stem. Extreme, in one Special cases may occur chondroblastoma contralateral cartilage growth, can in the metaphysis.

3. The natural course of chondroblastoma

Most of the lesions are stage 2 active lesions with symptoms, slow growth, a small part of stage 3 invasive lesions, lesions infiltrating adjacent joints or soft tissues, and malignant transformation of chondroblastoma is rare, more common in pelvis and chemotherapy, "benign "The distant metastasis of the lesion occasionally occurs.

According to clinical manifestations, combined with imaging examination, histological examination can be diagnosed, and chondroblastoma is one of the few tumors that can be diagnosed by freezing.

Examination of chondroblastoma

Pathological manifestations:

Gross specimen

The surface of the chondroblastoma is not seen to be derived from cartilage. After the incision, moderately reactive neovascularization and hyperplasia can be seen. The cyst is thin and easy to break through. There is dark purple tissue overflow into the lesion. This tissue is very It is fragile and has a distinct gritty feeling. The nodules are in cartilage-like tissue. It is mixed with other tissues, so that the origin of cartilage is not obvious. The large cystic area contains old blood. The blood chamber is empty like an aneurysm. A bone cyst.

2. See you under the microscope

Histological examination showed that the lesions contained chondroblasts, which were mixed with the fibrous matrix. There were a small amount of loose interstitial cells between the cells, sometimes a prominent cartilage-like matrix, which was characterized by calcification around the cells and a grid shape. Known as "plaid-like calcification", the cells are round and full, active, with only a small amount of immature matrix, in which large multinucleated giant cells are interspersed, sometimes functioning like osteoclasts, sometimes resembling macrophages, Because of its obvious characteristics, chondroblastoma is one of the few tumors that can be diagnosed by freezing.

Film degree exam

X-ray inspection

Quite typical, especially when the tumor is located in the epiphysis area, the osteolytic region of the chondroblastoma begins to locate in the epiphysis, tends to spread over the growing cartilage, and spreads to the metaphysis. When the body growth stops or is about to stop, the growth cartilage has disappeared or is about to disappear. When disappearing, such as continuous X-ray film, the tumor destruction and the surviving growth cartilage can be clearly seen. The chondroblastoma is a small or medium-sized tumor with a diameter ranging from 1 to 2 cm to 6 to 7 cm. The osteolytic bone is often central or eccentric. When the tumor originates from the great nodule of the humerus, the osteolytic bone is often located at the proximal end of the humerus, which is eccentric, round or slightly multi-ring, and its X-ray permeability is not very strong. Visible cloud-like or thin, weak, impervious X-ray particles, the boundaries of chondroblastoma are clearly defined, sometimes marked with thin lines of osteosclerosis, which are characteristic. In eccentric and expanded cases, cortical bone can expand to Almost disappeared, chondroblastoma can erode all of the subchondral bone, with little or no periosteal reaction in the metaphyseal cortex.

Usually, the lesion occurs in the epiphysis of the long bone. It is round or elliptical. It has a low-density shadow of 2 to 4 cm in diameter, and the edge is clear. The surrounding bone has a hardening margin. Some lesions can be seen with punctate calcification, and the corresponding backbone can be seen continuously. Periosteal reaction, sometimes lesions may be associated with aneurysmal bone cysts, X-ray films will show swelling, X-ray findings of chondroblastoma are characterized by a central or eccentric osteolytic lesion at the epiphysis or bony prominence. Its size is usually 5 ~ 6cm, the lesion boundary is clearly round or oval, there is a very thin hardened edge around the tumor to separate the tumor from normal tissue, adjacent cartilage can be thinned or eroded, the tumor can expand to the cartilage Lower bone, but rarely enter the joint space, 30% to 50% of cases have calcification in the lesion, because the degree of calcification is not the same, sometimes with the help of X-ray or CT to determine certain calcifications, about In 30% of cases, periosteal reaction occurs in the adjacent diaphysis or metaphysis, and it is rare for soft tissue to have mass and pathological fractures.

2. Radionuclide scanning

The amount of nuclide uptake in the lesion area is increased, which is consistent with the range of lesions displayed on the X-ray film. Because the nuclide intake of the tarsal plate is also high and interferes with the lesion, the nuclides cannot accurately judge the lesion.

3. Angiography

Significant enhancement can be shown, although it is not as rich in blood vessels as bone giant cell tumors, but has more blood vessels than other cartilage lesions.

4.CT

CT can best show the characteristics of the lesion, which can clearly show the relationship between the lesion and the articular surface and the tarsal plate. It can clearly show the calcification point, in addition to determining the calcification of the chondroma or understanding the extent of the tumor to the metaphysis. In addition to X-ray tomography or CT examination, special imaging studies are generally not required.

5.MRI

The lesion is a low signal on the T1, T2-weighted image, and MRI can accurately show the extent of the lesion, often used to determine the boundary of the tumor to soft tissue invasion.

Diagnosis and identification of chondroblastoma

From the perspective of imaging, it must be differentiated from giant cell tumor of bone, but only in adulthood, because if the growth cartilage still exists, the giant cell tumor of the bone does not invade the epiphysis. An important difference between the two is the cartilage. Cell tumors often have clear boundaries, while the boundaries of giant cell tumors are blurred. The second difference is that there may be cloud-like calcification in chondroblastoma. Histologically, even in the absence of calcification and cartilage-like differentiation, giant Cell-rich areas, chondroblastoma can also be clearly distinguished from giant cell tumors of the bone, because the basal cells of chondroblastoma have more defined boundaries, some like chimeric fragments, and the distribution of giant cells is irregular, mainly focused on bleeding. District, mitosis is rare.

In the image, chondroblastoma is very similar to clear cell chondrosarcoma, including calcification. These chondrosarcomas are found in adults and are clearly histologically distinct from chondroblastoma.

The rare chondroma or central chondrosarcoma located in the epiphysis can resemble chondroblastoma in terms of imaging, but their gross pathology and histopathology are different.

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