Bone Tumor

Essential Information

Summarize

1. Normal bone tissue

  

        Bones hold up the human body.

 

        The hard outer layer of bone consists of dense bone (bone cortex) and an inner layer of relatively light cancellous bone (trabeculae), with the dense bone wrapped around the cancellous bone. The outer layer of bone is covered by a layer of fibrous tissue called periosteum. Some of the bone is hollow, and within this hollow bone is a space called the marrow cavity, which is rich in bone marrow. The tissue lining the marrow cavity is called endosteum. At the ends of the marrow are relatively soft bone-like structures called cartilage. Cartilage is softer than bone, but still tougher than most tissues. Cartilage is made up of a fibrous matrix surrounded by a calcium-free gelatinous substance. Most bone originates from cartilage. The body forms bone by depositing layers of calcium into cartilage. After the bones are formed, a portion of cartilage located at the ends evolves as a cushioning component between the bones. This cartilage, along with ligaments and other tissues, forms the joints that connect the bones.

 

        Bone itself is hard. Bone contains two types of cells: osteoblasts, which form new bone, and osteoclasts, which destroy old bone. Although the bone does not appear to change much from the outside, it is actually very active. New bone is being created and old bone is being destroyed all over the body all the time.

 

        In some bones, the bone marrow consists only of adipose tissue. In other bones, the bone marrow is a mixture of fat cells and hematopoietic cells. Hematopoietic cells are the cells that make red blood cells, white blood cells, and platelets. There are other cell types in the bone marrow, including plasma cells, fibroblasts, and reticuloendothelial cells.

 

        Any of these cells are capable of developing into a tumor, either benign or malignant.

 

 

Etiolog & Risk factors

 etiology

 

       Malignant bone tumors occurring in children and adolescents are partially associated with genetic mutations. In rare cases, chemotherapy or radiation therapy for other tumors may increase the chance of developing a second bone tumor.

 

Classification & Stage

 Types of Bone Tumors

 

        There are several types of bone tumors. People name different types of bone tumors based on two factors: the location of the affected bone and surrounding tissues; and the type of cells that form the tumor (e.g., osteoblastoma, osteochondroma, etc.). Primary bone tumors can be benign or malignant.

 

        Osteomas and sarcomas are often confused and are sometimes really difficult to distinguish. In general, malignant tumors that originate in the bones are usually called osteomas (sometimes called osteosarcomas), while those that originate in a variety of tissues such as muscle, fibrous tissue, blood vessels, and fat are called sarcomas.

 

        2.1 Benign bone tumors

 

        Benign skeletal tumors include: osteoid osteoma, osteoblastoma, osteochondroma, endogenous chondrosarcoma, and mucinous fibroma of cartilage. Benign tumors do not or rarely spread to other tissues and organs, so they are usually not life-threatening and can often be cured surgically.

 

        2.2 Malignant Bone Tumors

 

        Osteosarcoma and Ewing sarcoma are the most common types of malignant skeletal tumors in children.

 

        2.2.1 Osteosarcoma

 

        Osteosarcoma is the most common malignant tumor that occurs in bone. Similar to osteoblasts in normal bone, osteoblasts in osteosarcoma produce bone matrix. However, the bone matrix in osteosarcoma is not as hard as normal tissue. Osteosarcoma can appear at any age, but most osteosarcomas occur in children or young adults, with adolescents being the most susceptible age group.

 

        2.2.2 Ewing sarcoma

 

        Ewing sarcoma is the second most common type of malignant bone tumor in children, adolescents, and young adults.James Ewing first described this type of malignant tumor in 1921, and it is named after him. Most Ewing sarcomas occur in the bones, but can also originate in other tissues and organs. The most common locations for this tumor to occur are the lower extremities, pelvis, and chest wall (e.g., ribs or scapula). Ewing sarcoma is most common in children and adolescents and is rare in adults older than 30 years of age.

 

        2.2.3 Chondrosarcoma

 

        Chondrosarcoma is a primary malignant tumor of bone originating from chondrocytes. It is rare in people younger than 20 years of age. Chondrosarcoma can develop anywhere there is cartilage, mostly in the bones of the pelvis, lower limbs or arms, and occasionally in the trachea, larynx and chest wall. Other locations include the shoulder blades, ribs or skull.

 

         2.2.4 Malignant fibrous histiocytoma

 

        Malignant fibrous histiocytomas are more likely to occur in soft tissues (connective tissues such as ligaments, tendons, fat, and muscle) than in bone. The name has now been changed to pleomorphic undifferentiated sarcoma. When malignant fibrous histiocytoma is present in the bones, it usually affects the legs (often near the knees) or arms. This malignant tumor is usually seen in the middle-aged and older population and is rare in children.

 

         2.2.5 Fibrosarcoma

 

        Fibrosarcomas are another group of malignant tumors of mesenchymal origin that occur more frequently in soft tissue than in bone. Fibrosarcoma is usually seen in the middle-aged and elderly population. It can involve the bones of the legs, arms, and jaw.

 

         2.2.6 Giant cell tumor of bone

 

        There are benign and malignant forms of these primary bone tumors. The benign form is the most common. Giant cell tumors of bone typically affect the bones at the leg (usually near the knee) or arm in adolescents and middle-aged adults. They do not often spread to more distant locations, but after surgery they often recur in the location where they started (called localized recurrence). This may happen several times. After each recurrence, the likelihood of the tumor spreading to other parts of the body becomes greater. In rare cases, malignant giant cell tumor of bone spreads to other parts of the body without local recurrence.

 

         2.2.7 Chordoma

 

        These primary bone tumors are usually found in the bones at the base of the skull and spine, and often occur in people over the age of 30, about twice as often in men as in women. Chordomas tend to be slow-growing and infrequently spread to other parts of the body, but often recur in situ if not completely removed. The lymph nodes, lungs and liver are common areas of secondary tumor spread.

 

        2.3 Other malignant tumors occurring in bone

 

        2.3.1 Non-Hodgkin's Lymphoma

 

        Non-Hodgkin's lymphoma usually occurs in the lymph nodes, but sometimes begins in the bones. Because it often occurs in multiple locations in the body, primary bone non-Hodgkin's lymphoma tends to spread more widely. Unlike treating primary osteosarcoma, the treatment for primary bone non-Hodgkin's lymphoma is the same as for lymphoma that begins in the lymph nodes.

 

        2.3.2 Multiple myeloma

 

       Multiple myeloma almost always occurs in the bones, but doctors do not consider it to be a primary malignant bone tumor because it develops from plasma cells in the bone marrow (the soft interior of some bones). Although it causes destruction of bone structure, it is neither a primary malignant bone tumor nor a leukemia. Sometimes myeloma first appears as a single tumor (called a plasmacytoma) in just one bone, but most of the time it spreads to the bone marrow of other bones.

 

Clinical manifestations

 

1. Clinical manifestations

 

       1.1 Pain

 

       The most common symptom in patients with bone tumors is pain within the bones. Initially, the pain is not constant. Symptoms may worsen at night or when the patient uses this bone (e.g. leg pain when walking). The pain will continue to occur as the tumor grows. The pain can worsen with the patient's activity, and in the case of leg bone problems, the patient may have difficulty walking.

 

       1.2 Swelling

 

       Swelling in the area of pain may not appear until weeks later. Depending on the location of the tumor, the lump may be palpable when touched. Tumors that occur in the bones of the neck can produce a lump in the back of the throat, causing difficulty swallowing or breathing.

 

       1.3 Fractures

 

      Bone tumors may weaken their affected bones, but in most cases no fracture occurs. Patients who break bones adjacent to the tumor often experience sudden, severe pain in the extremities.

 

       1.4 Other symptoms

 

       Bone tumors that occur in the spine can press on nerves, causing numbness, tingling, and even weakness in the limbs. Malignant bone tumors may cause weight loss and fatigue. If the tumor spreads to other organs, it can also cause symptoms. For example, if the tumor spreads to the lungs, the patient may have difficulty breathing.

 

2. Examination & Diagnosis

       A patient's symptoms, physical examination, imaging tests and blood test results may suggest the presence of bone cancer. However, in most cases, the doctor must confirm the presence and nature of the tumor by examining a sample of tissue or cells under a microscope (i.e., a biopsy, or biopsy for short).

 

Clinical Management

       The main treatments for bone tumors include: surgery, radiotherapy, chemotherapy and targeted therapy. A variety of tools are usually used, and common treatment options are determined according to the different degrees of bone tumors.

 

Prognosis

prognosis

        For all bone tumors (both adult and pediatric), the 5-year survival rate is about 70%.

        Survival rates are often based on the outcomes of a large number of previous patients, but they do not predict what will happen in any particular case. Many factors can affect patient outcomes, such as the type and grade of the tumor, the patient's age, the location of the tumor, the size of the tumor, and the treatment received. As familiar with your particular condition. Your doctor will be able to tell you to what extent those numbers can apply to you.

 

 

References

 

 

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        5. Wodowski K, Hill DA, Pappo AS, et al. A chemosensitive pediatric extraosseous osteosarcoma: case report and review of the literature. J Pediatr J Pediatr Hematol Oncol 25 (1): 73-7, 2003. [PUBMED Abstract]

        6. Chen X, Bahrami A, Pappo A, et al. Recurrent somatic structural variations contribute to tumorigenesis in pediatric osteosarcoma. Cell Rep 7 (1): 104- 12, 2014. [PUBMED Abstract]

        7. Perry JA, Kiezun A, Tonzi P, et al. Complementary genomic approaches highlight the PI3K/mTOR pathway as a common vulnerability in osteosarcoma. Proc Natl Acad Sci U S A 111 (51): E5564-73, 2014.[PUBMED Abstract]

        8. Harris MB, Gieser P, Goorin AM, et al. Treatment of metastatic osteosarcoma at diagnosis: a Pediatric Oncology Group Study. J Clin Oncol 16 (11): 3641-8 J Clin Oncol 16 (11): 3641-8 , 1998. [PUBMED Abstract

        9. Pakos EE, Nearchou AD, Grimer RJ, et al. Prognostic factors and outcomes for osteosarcoma: an international collaboration. Eur J Cancer 45 (13): 2367-75, 2009. [PUBMED Abstract]. Eur J Cancer 45 (13): 2367-75, 2009. [PUBMED Abstract