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SpecialtyOsteoblastoma_header_cell_0_1_0 Oncology Q1807280?uselang=en#P1995Osteoblastoma_cell_0_1_1

Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone. Osteoblastoma_sentence_0

It has clinical and histologic manifestations similar to those of osteoid osteoma; therefore, some consider the two tumors to be variants of the same disease, with osteoblastoma representing a giant osteoid osteoma. Osteoblastoma_sentence_1

However, an aggressive type of osteoblastoma has been recognized, making the relationship less clear. Osteoblastoma_sentence_2

Although similar to osteoid osteoma, it is larger (between 2 and 6 cm). Osteoblastoma_sentence_3

Signs and symptoms Osteoblastoma_section_0

Patients with osteoblastoma usually present with pain of several months' duration. Osteoblastoma_sentence_4

In contrast to the pain associated with osteoid osteoma, the pain of osteoblastoma usually is less intense, usually not worse at night, and not relieved readily with salicylates (aspirin and related compounds). Osteoblastoma_sentence_5

If the lesion is superficial, the patient may have localized swelling and tenderness. Osteoblastoma_sentence_6

Spinal lesions can cause painful scoliosis, although this is less common with osteoblastoma than with osteoid osteoma. Osteoblastoma_sentence_7

In addition, lesions may mechanically interfere with the spinal cord or nerve roots, producing neurologic deficits. Osteoblastoma_sentence_8

Pain and general weakness are common complaints. Osteoblastoma_sentence_9

Pathophysiology Osteoblastoma_section_1

The cause of osteoblastoma is unknown. Osteoblastoma_sentence_10

Histologically, osteoblastomas are similar to osteoid osteomas, producing both osteoid and primitive woven bone amidst fibrovascular connective tissue, the difference being that osteoblastoma can grow larger than 2.0 cm in diameter while osteoid osteomas cannot. Osteoblastoma_sentence_11

Although the tumor is usually considered benign, a controversial aggressive variant has been described in the literature, with histologic features similar to those of malignant tumors such as an osteosarcoma. Osteoblastoma_sentence_12

Diagnosis Osteoblastoma_section_2

When diagnosing osteoblastoma, the preliminary radiologic workup should consist of radiography of the site of the patient's pain. Osteoblastoma_sentence_13

However, computed tomography (CT) is often necessary to support clinical and plain radiographic findings suggestive of osteoblastoma and to better define the margins of the lesion for potential surgery. Osteoblastoma_sentence_14

CT scans are best used for the further characterization of the lesion with regard to the presence of a nidus and matrix mineralization. Osteoblastoma_sentence_15

MRI aids in detection of nonspecific reactive marrow and soft tissue edema, and MRI best defines soft tissue extension, although this finding is not typical of osteoblastoma. Osteoblastoma_sentence_16

Bone scintigraphy (bone scan) demonstrates abnormal radiotracer accumulation at the affected site, substantiating clinical suspicion, but this finding is not specific for osteoblastoma. Osteoblastoma_sentence_17

In many patients, biopsy is necessary for confirmation. Osteoblastoma_sentence_18

Treatment Osteoblastoma_section_3

The first route of treatment in Osteoblastoma is via medical means. Osteoblastoma_sentence_19

Although necessary, radiation therapy (or chemotherapy) is controversial in the treatment of osteoblastoma. Osteoblastoma_sentence_20

Cases of postirradiation sarcoma have been reported after use of these modalities. Osteoblastoma_sentence_21

However, it is possible that the original histologic diagnosis was incorrect and the initial lesion was an osteosarcoma, since histologic differentiation of these two entities can be very difficult. Osteoblastoma_sentence_22

The alternative means of treatment consists of surgical therapy. Osteoblastoma_sentence_23

The treatment goal is complete surgical excision of the lesion. Osteoblastoma_sentence_24

The type of excision depends on the location of the tumor. Osteoblastoma_sentence_25


  • For stage 1 and 2 lesions, the recommended treatment is extensive intralesional excision, using a high-speed burr. Extensive intralesional resections ideally consist of removal of gross and microscopic tumor and a margin of normal tissue.Osteoblastoma_item_0_0
  • For stage 3 lesions, wide resection is recommended because of the need to remove all tumor-bearing tissue. Wide excision is defined here as the excision of tumor and a circumferential cuff of normal tissue around the entity. This type of complete excision is usually curative for osteoblastoma.Osteoblastoma_item_0_1

In most patients, radiographic findings are not diagnostic of osteoblastoma; therefore, further imaging is warranted. Osteoblastoma_sentence_26

CT examination performed with the intravenous administration of contrast agent poses a risk of an allergic reaction to contrast material. Osteoblastoma_sentence_27

The lengthy duration of an MRI examination and a history of claustrophobia in some patients are limiting the use of MRI. Osteoblastoma_sentence_28

Although osteoblastoma demonstrates increased radiotracer accumulation, its appearance is nonspecific, and differentiating these lesions from those due to other causes involving increased radiotracer accumulation in the bone is difficult. Osteoblastoma_sentence_29

Therefore, bone scans are useful only in conjunction with other radiologic studies and are not best used alone. Osteoblastoma_sentence_30

Frequency Osteoblastoma_section_4

In the US, osteoblastomas account for only 0.5-2% of all primary bone tumors and only 14% of benign bone tumors making it a relatively rare form of bone tumor. Osteoblastoma_sentence_31

In regards to morbidity and mortality, conventional osteoblastoma is a benign lesion with little associated morbidity. Osteoblastoma_sentence_32

However, the tumor may be painful, and spinal lesions may be associated with scoliosis and neurologic manifestations. Osteoblastoma_sentence_33

Metastases and even death have been reported with the controversial aggressive variant, which can behave in a fashion similar to that of osteosarcoma. Osteoblastoma_sentence_34

This variant is also more likely to recur after surgery than is conventional osteoblastoma. Osteoblastoma_sentence_35

Osteoblastoma affects more males than it does females, with a ratio of 2–3:1 respectively. Osteoblastoma_sentence_36

Osteoblastoma can occur in persons of any age, although the tumors predominantly affect the younger population (around 80% of these tumors occurs in persons under the age of 30). Osteoblastoma_sentence_37

No racial predilection is recognized. Osteoblastoma_sentence_38

It usually presents in the vertebral column or long bones. Osteoblastoma_sentence_39

Approximately 40% of all osteoblastomas are located in the spine. Osteoblastoma_sentence_40

The tumors usually involve the posterior elements, and 17% of spinal osteoblastomas are found in the sacrum. Osteoblastoma_sentence_41

The long tubular bones are another common site of involvement, with a lower extremity preponderance. Osteoblastoma_sentence_42

Osteoblastoma of the long tubular bones is often diaphyseal, and fewer are located in the metaphysis. Osteoblastoma_sentence_43

Epiphyseal involvement is extremely rare. Osteoblastoma_sentence_44

Although other sites are rarely affected, several bones in the abdomen and extremities have been reported as sites of osteoblastoma tumors. Osteoblastoma_sentence_45

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Osteoblastoma.