|
https://upload.orthobullets.com/topic/8012/images/Osteoid Osteoma - Xray - proximal fibula_moved.jpg
https://upload.orthobullets.com/topic/8012/images/Osteoid Osteoma - CT scan_moved.jpg
https://upload.orthobullets.com/topic/8012/images/Osteoid Osteoma - Histology_moved.jpg
https://upload.orthobullets.com/topic/8012/images/osteoid17.jpg
https://upload.orthobullets.com/topic/8012/images/case b - prox humerus - xray - parsons_moved.png
https://upload.orthobullets.com/topic/8012/images/Case B - femur - xray - Parsons_moved.png
Introduction
  • A small, discrete, painful, benign bone lesion 
  • Epidemiology
    • incidence
      • cause of painful scoliosis in the adolescent population 
    • demographics
      • 3:1 male to female ratio
      • persons aged 5-25 years (>80% present before age of 30)
    • location
      • most common
        • lower extremity (>50%)
          • proximal femur > tibia diaphysis
          • usually found within the bone cortex
        • spine (10-15%)
          • thoracic and lumbar regions > cervical and sacral
          • majority involve the posterior elements
          • usually found on the side of concavity in scoliosis
        • hand (5-10%)
          • scaphoid and proximal phalanx
        • foot (<5%)
          • predominantly involves the talar neck
  • Pathophysiology
    • pathoanatomy  
      • nidus
        • central nodule of woven bone and osteoid with osteoblastic rimming
      • reactive zone
        • area of thickened bone and fibrovascular tissue
    • cellular biology
      • pain 
        • attributed to increased local concentration of prostaglandin E2 and COX1 & 2 expression 
        • increased number and size of unmyelinated nerve fibers within the nidus
  • Associated conditions
    • orthopaedic manifestations
      • painful scoliosis
      • growth disturbance
      • flexion contractures
  • Prognosis
    • pain from lesions usually resolves after an average of 3 years
    • the lesion spontaneously resolves in 5-7 years
    • in the spine, early resection (within 18 months) leads to resolution of scoliosis in young children (<11years)
Classification
 
Enneking Classification of Benign Lesions
Stage Grade Examples
Images 
Stage 1 Latent lesions enchondroma, non-ossifying fibroma  
Stage 2    Active lesions osteoid osteoma, UBC
Stage 3 Aggressive lesions giant cell tumor of bone, ABC, chondroblastoma, chondromyxoid fibroma,   
 
Symptoms
  • Symptoms
    • pain
      • constant and progressive
      • worse at night and with drinking ETOH
      • relieved by NSAIDS 
      • may be adjacent to joint and mimic arthritis
    • hand lesions may present with painless swelling
  • Physical exam
    • inspection
      • palpable bone
        • deformity, swelling, erythema, tenderness
      • proximity to a joint
        • effusion, contracture, limp, muscle atrophy
      • spine
        • postural scoliosis, paravertebral muscle spasm
Imaging
  • Radiographs
    • recommended views
      • 3 views of affected bone or joint
    • findings
      • intensely reactive bone around radiolucent nidus 
  • CT 
    • indication 
      • cross-sectional imaging is the study of choice
    • findings
      • to help identify the location and size of nidus  
        • usually < 1.5 cm (otherwise think osteoblastoma)
  • Bone scan 
    • indication
      • concerning features on radiograph or advanced imaging
    • findings
      • intense hot area of focal uptake at the nidus 
      • low uptake in reactive zone  
        • known as the 'double-density sign'
  • MRI
    • indications
      • usually not recommended as it can mimic aggressive lesions
    • findings
      • must be interpreted with reference to x-ray or CT scan
Histology
  • Histology
    • distinct demarcation between nidus and reactive bone  
      • nidus 
        • contains uniform osteoid seams of immature osteoid trabeculae (woven bone) with a sharp border of osteoblastic rimming 
        • uniform plump osteoblasts have regularly shaped nuclei with abundant cytoplasm 
      • reactive zone
        • region surrounding the sclerotic border
Differentials
  • Long bone osteoid osteomas need to be differentiated from
    • stress fx
    • osteomyelitis
    • Ewing's sarcoma
  • Posterior spinal element lesions need to be differentiated from
    • aneurysmal bone cyst
    • osteoblastoma (see table below)

Osteoid Osteoma
Osteoblastoma
Incidence 10% of benign tumors 3% of benign tumors
Size

< 2 cm (typically <1.5cm)

>2 cm (average, 3.5 - 4.0 cm)
Site > 50 % in long bone diaphysis
> 35% in posterior elements of the spine
Location Proximal femur > tibia diaphysis > spine vetebral column > proximal humerus > hip
Natural History Self-limited Progressive
Histology

Benign appearance. No growth potential. Central nidus composed of more organized osteoid and lined by osteoblasts. 

Benign appearance. Localized growth, with aggressive potential. Central lesion less organized, with greater vascularity. 
Symptoms Nocturnal pain, relieved by NSAIDS Dull ache, not relieved by NSAIDS. >50% of spine tumors have neurologic symptoms.
Management of Spine Lesions Nonsurgical management is indicated as first-line treatment.  Surgery is always indicated as they do not respond to nonsurgical treatment.
 
Treatment
  • Nonoperative
    • clinical observation and NSAID administration 
      • indications
        • NSAIDS are 1st line and will lead to a dramatic decrease in symptoms 
          • ~50% can be treated with NSAIDS alone
        • also indicated for painful spine lesions without scoliosis
        • fingertip lesions (distal phalanx) may not respond to NSAIDS
  • Operative
    • percutaneous radiofrequency ablation       
      • relative indications
        • failure of medical management
        • periarticular lesions, which increase the risk of cartilage injury and premature degenerative disease.
        • spinal lesions (controversial) - depends on the location of the lesion and proximity to neural elements
      • contraindications
        • lesions close to spinal cord or nerve roots
      • technique
        • done under CT guidance
        • probe at 80-90 deg C for 6 minutes to produce a 1cm zone of necrosis
      • outcomes
        • 90% of patients are successfully treated with 1-2 sessions of RFA
        • 10-15% recurrence rate
    • surgical resection with currettage  
      • indications
        • location of lesion is not amenable to CT guided percutaneous radiofrequency ablation   
          • e.g. close to skin or nerve
        • spine lesion associated with painful scoliosis
        • digital lesions 
          • RFA carries risk of thermal skin necrosis and injury to digital neurovascular bundle
      • technique
        • successful treatment depends on complete marginal resection of nidus (sclerotic bone is normal and can be left behind) 
          • percutaneous approach 
          • open approach
      • outcomes
        • 94% success with local excision
        • associated scoliosis rarely requires treatment
Complications
  • Recurrence
    • 10-15% recurrence rate with percutaneous radiofrequency ablation
Image Bank
 
Location
Xray
CT
Bone scan
MRI
MRI
Histo
Case A tibia
 
 
Case B prox. femur  
 
Case C tibia
Case D prox tibia  

 

Please rate topic.

Average 4.1 of 66 Ratings

Questions (17)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(OBQ09.197) A 17-year-boy has had chronic hip pain for the last 8 months that no longer responds to nonsteroidal anti-inflammatory medications. He reports that the pain is worse at night. He is afebrile and laboratory studies, including an ESR, C-reactive protein, and CBC are within normal limits. Radiographs, computed tomography, and a bone scan are shown in Figure A, B, and C respectively. What is the next step in management? Review Topic

QID: 3010
FIGURES:
1

CT guided biopsy

8%

(98/1302)

2

CT of chest , abdomen, and pelvis

4%

(58/1302)

3

CT guided radiofrequency ablation

81%

(1050/1302)

4

En bloc surgical resection resection

2%

(28/1302)

5

Open surgical curettage with chemical cauterization and cementing

5%

(65/1302)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(SBQ04PE.40) A 6-year-girl continues to complain of pain for 8 months in the mid-tibia region that persists despite temporary relief with use of nonsteroidal anti-inflammatory medications. The pain is severe enough that it limits her activities of daily living, such as going to school and sleeping. She is afebrile and laboratory studies, including an ESR, C-reactive protein, and CBC are within normal limits. Radiographs and computed topography are shown in Figure A and B. Figure C shows the histology from a needle biopsy. What is the next step in management? Review Topic

QID: 37
FIGURES:
1

Observation with repeat radiographs in 6 months

3%

(25/748)

2

Percutaneous radiofrequency ablation

85%

(634/748)

3

Wide surgical resection

7%

(54/748)

4

Chemotherapy

3%

(19/748)

5

Broad spectrum parenteral antibiotics for 6 weeks.

1%

(5/748)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(OBQ08.85) A 17-year-old runner presents to your office with shin pain of 6 months duration. The pain is not activity related and is made better by NSAIDS. The pain is not changed with cessation of running. Based on the clinical picture, you are concerned about an osteoid osteoma. Which of the following histology slides would confirm your diagnosis. Review Topic

QID: 471
FIGURES:
1

Figure A

13%

(75/578)

2

Figure B

8%

(48/578)

3

Figure C

15%

(86/578)

4

Figure D

9%

(52/578)

5

Figure E

54%

(310/578)

Select Answer to see Preferred Response

PREFERRED RESPONSE 5

(OBQ12.48) A 17-year-old female presents for re-evaluation of her diffuse thoraco-lumbar spine pain. She had previously been evaluated at the age of 14 for the same symptoms. At that time she was diagnosed with scoliosis and prescribed brace therapy which has offered her no relief. A current radiograph, CT scan, and bone scan of the affected area are shown in Figures A,B and C respectively. Lab workup including CRP, ESR, and WBC is normal. What is the most likely diagnosis and cause of persistent pain in this patient? Review Topic

QID: 4408
FIGURES:
1

Idiopathic scoliosis

3%

(109/3861)

2

Giant cell tumor

3%

(106/3861)

3

Osteoid osteoma

93%

(3579/3861)

4

Vertebral osteomyelitis

1%

(21/3861)

5

Metastatic osteosarcoma

1%

(21/3861)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

(OBQ12.11) A 24-year-old man has had pain in the right index finger for the past 9 months. The pain is completely
relieved with ibuprofen. An AP radiograph and CT scan are shown in Figures A and B respectively. Which of the following is true regarding this lesion? Review Topic

QID: 4371
FIGURES:
1

Radiation and chemotherapy is required for definitive treatment

1%

(43/4217)

2

An increase in cyclooxygenase activity has been demonstrated within these lesions

89%

(3746/4217)

3

Spontaneous resolution does not occur

5%

(212/4217)

4

A definitive diagnosis cannot be made without MRI

2%

(97/4217)

5

Pain is most severe during the day, and typically improves at night

2%

(91/4217)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

(OBQ09.6) A 27-year-old male presents with an acute onset of low back and right leg pain following a water skiing accident two weeks ago. His physical exam shows no neurological deficits. Lumbar spine radiographs are normal. An axial and coronal CT scan are shown in Figure A and B. What is the first line of treatment? Review Topic

QID: 2819
FIGURES:
1

Magnetic Resonance Imaging (MRI)

8%

(187/2425)

2

CT guided percutaneous biopsy

4%

(95/2425)

3

CT guided radiofrequency ablation

14%

(344/2425)

4

Open surgical curettage with chemical cauterization and cementing

7%

(174/2425)

5

Continued clinical observation

67%

(1618/2425)

Select Answer to see Preferred Response

PREFERRED RESPONSE 5
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
ARTICLES (28)
VIDEOS (4)
CASES (1)
GROUPS (1)
Topic COMMENTS (19)
Private Note