Common Benign Tumors

Chapter 58

Common Benign Tumors

Osteoid Osteoma


Osteoid osteoma (Figure 58-1) comprises about 11% of all benign bone tumors in children.

It has a boy-to-girl predominance of about 3:1.

It is most commonly found in the femur and tibia, but it is also found elsewhere in the skeleton, including the posterior elements of the spine.


Constant pain that may be worse at night

Nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin usually provide complete or nearly complete pain relief.

Physical activity does not affect pain.

Physical examination may reveal a limp or disuse atrophy of the affected extremity.

Joint examination findings, including range of motion, will be normal.

Palpation may reveal the site of the lesion if it is located in an area without significant overlying soft tissue, such as the proximal tibia.

Scoliosis may be observed with spinous process lesions, but it occurs without the traditionally accompanying rotational deformity.


Figure 58-1. Osteoid osteoma of the femoral neck (circled) in a college runner 18 years of age. Patient presented with right-side groin pain.


Radiographs may be diagnostic, revealing an area of dense, reactive bone surrounding a radiolucent nidus (see Figure 58-1).

Computed tomography (CT), magnetic resonance imaging (MRI), or bone scan

May be necessary to identify lesions in the proximal femur or posterior spine

Useful for identifying early lesions because onset of pain may precede findings on plain radiographs

Biopsy may be performed to confirm the diagnosis.


Biopsy will differentiate an osteoid osteoma from infection and a malignant bone tumor. Also, patients with an osteoid osteoma are unlikely to have fever, which is common in patients with Brodie abscess and osteomyelitis.

Histologically, an osteoblastoma appears the same as an osteoid osteoma; differentiation is based on the size of the lesion, with an osteoid osteoma being less than 2 cm.


The preferred treatment is symptomatic care with NSAIDs.

Radiofrequency ablation (RFA) or en block resection is considered for cases not responsive to symptomatic care.

If RFA is not safe because the lesion is adjacent to neurologic structures, percutaneous coring or drilling is an option.

Biopsy is performed to confirm the diagnosis prior to RFA or resection.


Spontaneous resolution of an osteoid osteoma lesion may occur 30 to 40 months after onset of symptoms.

After RFA, the child can resume physical activity as tolerated, without restriction.

Successful treatment of spinal osteoid osteoma lesions that cause scoliosis can lead to resolution of scoliosis.


Refer to a pediatric orthopaedic surgeon for treatment once the lesion is identified.


American Academy of Orthopaedic Surgeons definition of osteoid osteoma (–conditions/osteoid-osteoma)



Osteoblastoma is a rare benign bone tumor histologically identical to osteoid osteoma.

It comprises 1% of primary bone tumors and 3.5% of benign bone tumors.

It has a boy-to-girl predominance of 2 to 3:1.

Most patients present between 10 and 20 years of age.


Pain is the primary symptom.

NSAIDs and aspirin therapy may provide pain relief, but the relief may not be as dramatic as that of an osteoid osteoma.

Soft tissue swelling may be present.

Occasionally, patients may notice a mass.

Lesions in extremities may cause a limp or disuse atrophy.

About 50% of osteoblastoma lesions are located in the spine and may cause a decreased range of motion, painful scoliosis, or neurologic signs and symptoms


An osteoblastoma is histologically identical to an osteoid osteoma, but an osteoblastoma is larger (nidus size > 2 cm) and pain from it is not as readily relieved with NSAIDs.

An aneurysmal bone cyst (ABC) (Figure 58-2) is clinically and radiographically similar to an osteoblastoma, although ABC usually expands the bone more than osteoblastoma; biopsy will differentiate the two conditions. Also, secondary ABCs can be seen in 10% to 40% of osteoblastomas.


Figure 58-2. Aneurysmal bone cyst defined by a radiograph (A) and a magnetic resonance imaging scan (B).

On radiographs an osteosarcoma is more invasive than an osteoblastoma, causing cortical destruction and significant periosteal reaction; biopsy rules out malignancy.


Results of laboratory studies are usually normal.

Findings on plain radiographs are often nonspecific.

The lesion is usually diaphyseal or metaphyseal and may be cortical or intramedullary.

Cortical lesions expand the cortex and have a thin rim of reactive bone.

The lesion has mixed qualities with radiodense and radiolucent areas.

Typical findings in the spine include enlargement of the spinous process, decreased pedicle definition, and irregular cortex.

Bone scan or CT scan may be necessary to locate and further evaluate spinous process lesions, which may be difficult to identify on radiographs.

CT scan may also help to differentiate from malignant lesions, which is sometimes difficult with radiographs.


Some smaller lesions may be followed with serial radiographs.

Lesions are often locally aggressive and require wide surgical resection to prevent damage to surrounding structures. More recently, RFA has been shown to be a safe and effective treatment modality for spinal osteoblastoma.


As with an osteoid osteoma, if spine lesions are identified and treated within 15 months after onset of symptoms, associated scoliosis will resolve or decrease significantly.

Rarely, sarcomatous degeneration of osteoblastoma lesions has been reported.


Refer to a pediatric orthopaedic oncologist once the lesion is identified.


Medscape definition of osteoblastoma (

Exostosis (Osteochondroma)


Exostosis, or osteochondroma, is a common benign lesion, accounting for 10% of all tumors and 30% of all benign bone tumors (Figure 58-3).


Figure 58-3. Sessile exostosis of the distal femur in a boy 10 years of age. This boy presented with a painless mass.


Most patients present with a painless mass.

Some patients may report pain because of repeated trauma to the exostosis or due to bursitis that can develop from repetitive friction of the tense overlying soft tissues.

Some patients present with a pathologic fracture of the osteochondroma.

In asymptomatic patients, lesions are identified on radiographs obtained for other reasons.

Large lesions may limit joint range of motion, cause neural or vascular compression, or irritate overlying muscle.

Physical examination reveals a non-tender, fixed mass.

Range of motion of the adjacent joint may be limited.

If nerve compression is present, isolated peripheral neurologic signs will be noted.


Multiple hereditary exostoses (MHE) is an autosomal-dominant syndrome in which patients have multiple exostoses.

Lesions may cause growth disturbance, loss of joint motion, and joint deformity.

Short stature and deformity of the radius and ulna are common.


The diagnosis can usually be established with radiographs.

The exostosis may be pedunculated or sessile and is in continuity with the medullary canal of the bone (see Figure 58-3).

Advanced imaging is usually unnecessary, but if the diagnosis is unclear on a plain radiograph, an MRI or CT scan can help establish the diagnosis.


Surgical intervention in the pediatric age group is indicated if the lesion restricts joint mobility, irritates the overlying muscle, or causes pain due to nerve compression, fracture, or repeated trauma.

Lesions should be radiographically evaluated annually.


Exostoses grow until skeletal maturity.

Malignant degeneration is rare but should be considered if there has been rapid growth of the exostosis after skeletal maturity and significant increase in pain.

Pathologic fractures may occur during physical activity.

Secondary chondrosarcoma is also rare, but patients with MHE are at greater risk than those with a solitary exostosis.


Refer to a pediatric orthopaedic surgeon once the lesion is identified.


American Academy of Orthopaedic Surgeons definition of osteochondroma (–conditions/osteochondroma)



Enchondroma is a centrally located, metaphyseal, radiolucent, expansile lesion causing thinning of the cortex; such tumors comprise 11% of benign bone tumors (Figure 58-4).


Figure 58-4. Enchondroma of the fifth metacarpal in a boy 8 years of age. It is a centrally located, metaphyseal, lucent, expansile lesion causing thinning of the cortex. This boy presented with a painless mass in the finger.

This tumor is most commonly found in the phalanges of the hands and feet; other common locations include the proximal humerus and distal femur.


May be asymptomatic or may present with pain or a pathologic fracture

Physical examination may reveal tenderness at the site of the lesion and the affected digit, or the affected extremity may appear swollen.


Chondrosarcoma appears more aggressive on radiograph with cortical destruction; biopsy may be needed to definitively distinguish it from enchondroma.

Fibrous dysplasia is diaphyseal rather than metaphyseal and, in long bones, has a more ground-glass appearance, while an enchondroma has a more lytic appearance.

Multiple enchondroma, also called Ollier disease, is less common than a solitary enchondroma and is usually diagnosed in children younger than 10 years.

Lesions may be bilateral but are usually worse on one side.

Angular and shortening deformities of the extremities are common and may require surgical intervention.


Plain radiographs are obtained first and are often diagnostic.

Enchondromas are usually found in the metaphysis within the medullary canal, but epiphyseal lesions have been reported.

Lesions are lucent and expansile, and they may cause thinning of the cortex.

Periosteal reaction is not usually present.

MRI may be performed to confirm the diagnosis.

Lesions are well circumscribed and have a high signal intensity on T2-weighted images and an intermediate signal on T1-weighted images.


Asymptomatic enchondromas do not require treatment.

Symptomatic enchondromas and those associated with a fracture should be treated with curettage and bone grafting.


Unlike with solitary enchondroma, patients with multiple enchondromas are at risk for a secondary chondrosarcoma over time, particularly in the shoulder and pelvis.


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Mar 12, 2022 | Posted by in ORTHOPEDIC | Comments Off on Common Benign Tumors

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