Osteochondroma

Original Editors - James Mountain from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - James Mountain, Leana Louw, Admin, Elaine Lonnemann, WikiSysop, Lydia Xenou, Mariam Hashem and Claire Knott  

Definition/Description

Osteochondroma, also referred to as osteocartilaginous exostosis or plainly exostosis, is the most common benign bone tumor. It can present as solitory osteochondroma or as multiple osteochondromatosis. These tumors account for 10%-15% of all bone tumors, while representing 36% of all non-malignant bone tumors. Osteochondromas usually arise from the metaphysis of long bones, but can occur at other cortical bone metaphyses. The most common sites for these tumors are the distal femur, proximal humerus, and proximal tibia. They can be in flat bones, such as, the ilium ans scalupa, and rarely affect the spine. It is believed that these non-malignant tumors arise from unusual cartilaginous epiphyseal growth-plate tissue that spreads and grows by endochondral ossification.

These tumors may present with a stalk-like structure and are known as pedunculated. Osteochondromas without a stalk are called sessile exostoses.  

Prevalence

Solitary osteochondroma occur equally in males and females. Multiple osteochondroma affects males more than females, approximately 1.6:1. 

Average age of clinical presentation is 10 to 30 years of age.

Characteristics/Clinical Presentation

Osteochondromas are usually asymptomatic and present most commonly as a painless bump near a joint, usually the knee or the shoulder. Other symptoms may present and are usually associated with the location of the osteochondroma. If the osteochondroma is located under a tendon, it may cause a snapping effect with activity as the tendon moves over the tumor. Additional symptoms may present if the osteochondroma is located near nerves and blood vessels. For example, a tumor on the posterior aspect of the knee may result in numbness and tingling, periodic changes in blood flow, loss of pulse, or colour change in the limb secondary to nerve and blood vessel compression.

Possible Symptoms & Complications:

1. painless, palpable mass near a joint - knee and shoulder most commonly

2. numbness and tingling

3. snapping of tendon over tumor

4. restricted range of motion 

5. period changes in blood flow

6. loss of pulse in affected limb due to vascular compression

7. colour change in limb due to vascular compression

8. radiculopathy secondary to spinal tumors

9. bursa formation

10. pathological fracture - most of which occur at the knee (distal femur of proximal tibia)

11. infarction

12. osteomyelitis

Associated Co-morbidities

Radiculopathies and myelopathy may occur if the osteochondroma presents in the spine and places pressure on the spinal cord and/or nerve roots.

Medications

Medical treatment is usually not indicated for osteochondroma, since most times the condition is asymptomatic. Pain medication is only used if symptoms of pain present. Observation and regular monitoring is very important though.

Diagnostic Tests/Lab Tests/Lab Values

• X-Ray: Most commonly used to diagnose osteochondroma, as the excess bone growth can usually be picked up on a plain X-rays.  

 

• MRI: Magnetic resonance imaging can be used as well. Most times, MRI is used to examine whether or not cartilage is present on the surface of the exostosis. If excess cartilage is indeed present (>1.5cm), the tumor should be checked for possible malignancy. 

 

• CT Scan: Computed tomography may also be used to evaluate the presence and physical characteristics of an osteochondroma, but it is not commonly used.

Etiology/Causes

The etiology regarding the development of solitary osteochondroma is currently unknown. Multiple osteochondromatosis, on the other hand, does apear to have a genetic link. It is inherited in 70% of cases and has been associated with EXT 1 and EXT 2 genes. The association is currently not well understood and research is continuing to look into the link.

Systemic Involvement

Depending on the location of the tumor, osteochondroma may affect the nervous or vascular system. Tumor growth and formation may compress surrounding nerves and blood vessels resulting in possible numbness and tingling, pulse loss, and colour changes of the affected limb.

Medical Management (current best evidence)

Options regarding medical management of osteochondroma is indicated only if symptoms are present and depends on a variety of factors including age, severity, disease extent, and overall health. Observation is the best way to manage a non-symptomatic osteochondroma.

• If symptoms are present, the medical options include:

    1. pain medication

    2. surgery

             Solitary osteochondroma stalk resection.

• Solitary Osteochondromas -  generally do not require surgery and are usually monitored with regular X-rays. Surgery for solitary osteochondromas are only suggested when the exostosis has grown completely and a mature skeleton is observed on an X-ray. The reason for this is to decrease the chance of reoccurrence.

         - Surgery may be considered when:

             1. pain is experienced with activity

             2. pressure on a nerve or blood vessel

             3. presence of a larger cartilage cap 

             4. bone growth has fully matured 

• Multiple Osteochondromas - surgical removal is not indicated unless symptoms exist. It is very important to monitor osteochondromas though, epecially if multiple osteochondromas are present. If surgery is indicated, the tumor may be completely removed and a prosthesis may have to be used to replace any structural loss.
  

Physical Therapy Management (current best evidence)

Physical therapy is indicated most commonly for post-operative osteochondroma cases. Functional mobility will be the primary focus with the treatment addressing range of motion, strength, restoring proper biomechanics. 

Differential Diagnosis

Malignant transformation from osteochondroma to osteosarcoma is possible in both solitary and multiple osteochondroma. This happens in approximately 1% of solitay osteochondroma cases and 5-25% in multiple osteochondromas.

It is also important to track the thickness of the cartilage gap once the bone has fully matured. A cartilage gap greater than 1.5cm or 2.0cm may suggest malignant transformation.

Radiculopathy - Solitary spinal osteochondroma is rare, making up 2.5% of solitary osteochondromas. I has been shown to mimic symptoms associated with radiculopathy, usually cervical.

Case Reports/ Case Studies

Chin K, Kharrazi F, Miller B, Mankin H, Gebhardt M. Osteochondromas of the distal aspect of the tibia or fibula. Journal of Bone and Joint Surgery. 2000;82:1269.

Errani C, Jutte P, De Paolis M, Bacchini P, Mercuri M. Secondary synovial condromatosis in a bursa overlying an osteochondroma mimicking a peripheral chondrosarcoma-a case report. Acta Orthopaedica. 2007;78(5):701-704.

Frey K, Hosey R, Milbrandt T. Tibial osteochondroma in a high school football player. Human Kinetics – Att. 2008;13(6):36-37.

Moon K, Lee J, Kim Y, Kwak H, Joo S, Kim I, Kim J, Kim S. Osteochondroma of the cervical spine extending multiple segments with cord compression. Pediatric Neurosurgery. 2006;42:304-307.

Ratliff J, Voorhies R. Osteochondroma of the C5 lamina with cord compression: case report and review of the literature. Spine. 2000; 25(10):1293-1295.

Robbins M, Kuo S, Epstein R. Non-traumatic fracture of an osteochondroma mimicking malignant degeneration in an adult with hereditary multiple exostoses. Radiology Case Reports. 2008;3:99.

Samartzis D, Marco R. Osteochondroma of the sacrum: a case report and review of the literature. Spine. 2006;31(13):425-429.

Yoshida T, Matsuda H, Horiuchi C, Taguchi T, Nagao J, Aota Y, Honda A, Tsukuda M. A case of osteochondroma of the atlas causing obstructive sleep apnea syndrome. Acta Oto-Laryngologica. 2006;126:445-448.

Resources

http://orthoinfo.aaos.org/topic.cfm?topic=A00079

http://emedicine.medscape.com/article/1256477-overview

http://www.bonetumor.org/tumors-cartilage/osteochondroma

http://www.childrenshospital.org/az/Site1079/mainpageS1079P0.html

http://www.who.int/en/

http://www.merckmanuals.com/professional/sec04/ch044/ch044b.html?qt=Thygeson%2520superficial%2520punctate%2520keratitis&alt=sh

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