Diagnostic Imaging Corner

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Case Challenge

Michelle A Wessely
(1) Department of Radiology, Institut Franco-Europeen de Chiropratique

* Corresponding author

Address: Institut Franco-Europeen de Chiropratique (IFEC), 24
Boulevard Paul Vaillant Couturier, 94200 Ivry Sur Seine
Email: mwessely@ifec.net

Journal of the Academy of Chiropractic Orthopedists
March 2010, Volume 6, Issue 4
Received: March 2010
Accepted: March 2010

This article is available from: http://www.dcorthoacademy.com © 2010
Wessely and the Academy of Chiropractic Orthopedists
This is an Open Access article which permits unrestricted use,
distribution, and reproduction in any medium, provided the original
work is properly cited.

CASE HISTORY

A 16 year old female presented to a chiropractor in France with a history of a car accident within the previous week, where she had been a passenger in the rear of the car, which was hit from the back. No initial pain was felt, and following a visit to the emergency room/casualty, the patient was discharged. The patient then presented to the chiropractor with her mother to be examined for pain in her knees. The patient was already aware of a bony disorder that she suffered with, from an earlier age, which in general did not cause her any problems.

A. B.

 

• What are the imaging findings?
• What is your clinical/imaging diagnosis?
• What would your clinical management entail?

WHAT ARE THE IMAGING FINDINGS?

Digital radiographs of the right knee, AP (1a) and lateral (1b) following a road traffic accident in a 16 year old female which demonstrate multiple bony outgrowths (osteochondromas/exostoses) affecting the proximal tibia and fibular, as well as distal femur which also demonstrates mild bony expansion.

WHAT IS YOUR CLINICAL/IMAGING DIAGNOSIS?

Hereditary multiple exostosis (HME). There is no evidence of osseous trauma in the region of the osteochondromas, or elsewhere in the region imaged.

WHAT WOULD YOUR CLINICAL MANAGEMENT ENTAIL?

The clinical management of a patient with hereditary multiple exostosis will include adapting the approach to not include adjusting directly over a region with particularly a pedunculated osteochondroma, due to the possible fracture that may be induced. In addition, the clinician should remain astute with a patient affected by HME of any lesion that becomes painful, or around which a soft tissue mass is noted to be developing, since in a small percentage of patients, aggressive/malignant tumours may arise. No information is however available in the current literature describing the clinical chiropractic management of a patient with HME although one case report was provided of a patient presented to the chiropractic practice with HME. The report mentions that no treatment was offered for the patient but that they were counseled for the potential risks including malignant degeneration (1). This patient was treated with soft tissue techniques as well as joint stimulation.

DISCUSSION:

Hereditary multiple exostosis (HME) is a condition in which osteochondromas produce overgrowth of the metaphyseal regions of multiple bones. As the name implies, this is most often an inherited autosomal dominant condition, with 96% penetrance and has also been referred to as diaphyseal aclasis, referring to the abnormal development or modeling of bone. Other terms include external chondromatosis, or multiple osteochondromatosis. The two genes most strongly associated with HME, EXT1 and EXT2, are involved in the regulation of chondrocyte proliferation and differentiation during enchondral bone development (2).

Hereditary multiple exostosis occurs in both genders and is typically detected between the ages of 2 and 10 years old, most often by age 3 and is slightly more common in males than females (1.5:1). In 10% of the patients and as in this case, there is no family history, with the HME occurring sporadically. As the metaphyseal overgrowth occurs with the developing osteochondromas, the slowly growing, typically painless lumps or masses will be palpated, typically first by the child or guardian, with eventual presentation to a clinician, although sometimes HME comes to clinical light when imaging is performed for an unrelated reason, for example on a chest x-ray performed for a nonmusculoskeletal condition. Most osteochondromas associated with HME affect the lower limb, especially the proximal and distal tibia, as with this patient, but virtually any bone may be affected, including long, flat, irregular and tubular bones (3).

With upper extremity involvement, there may be bowing of the forearm, typically affecting primarily the ulna. Although the ulna shows overgrowth, it actually appears to be shorter than the radius, due to the bowing. Protruberances from the bone surface may cause symptoms related to the pressure effect of the osteochondroma, leading to bursitis, tendinitis, even the development of neurovascular abnormalities such as aneuyrsms or pseudoaneurysms. Fracture of the osteochondroma is a relatively common complication, especially when it is pedunculated (has a distinct stalk) rather than sessile (broad-based). Other common deformities include short stature, limb-length discrepancies, valgus deformities about the knees and ankles, Madelung’s deformity and asymmetry of the scapula and pelvic girdle. Neurologic complications may occur depending on the location of the osteochondroma, such as a case that was published of Brown-Sequard syndrome developing in a young patient with an exostosis affecting the cervical spine (4).

On conventional radiography, an osteochondroma is seen as an osseous density protruding from the bone with direct extension of the cortex of the parent bone around the ostechchondroma. When HME is detected, the work-up may include a skeletal survey, with focus on the ends of the long bones, including the shoulder and pelvic girdles, elbows, wrists and hand, knees and ankles. Depending on access to further imaging, ultrasound over the osteochondroma or magnetic resonance (MR) imaging may be utilized in order to evaluate the thickness of the cartilage cap surrounding the osteochondroma, especially in a case where there is clinical concern for malignant transformation. The most serious complication of HME is malignancy, most often a chondrosarcoma, arising from a previously benign osteochondroma, such as in the case published of a secondary chondrosarcoma arising from the cuboid bone of an osteochondroma in a patient with HME (5). This is significantly more common in HME than in individuals with a single osteochondroma and no HME. The potential for malignant transformation may vary with the thickness of the cartilage cap, the thicker the cap the more likely for malignant transformation. The final diagnosis of HME is made with a combination of the imaging findings, histology if available as well as the clinical history of both the patient and family. With malignant transformation, a patient may note pain in a previously non-painful region affected by an osteochondroma, or a newly growing soft tissue mass may be noted either by the patient or the clinician. In such a case, further imaging is required and MRI with and without contrast is the examination of choice, although ultrasound can be helpful, especially if MRI is not immediately available.

Treatment of HME depends on the clinical situation. If the patient is symptomatic or there is unwanted cosmetic deformity, orthopedic surgical techniques are available which attempt to realign the region involved. For example surgery may be performed on the wrist if the ulna and/or radius are affected. Bone lengthening procedures can also be used to improve the osseous relationships. Clinical observation needs to remain vigilant so as to determine the presence of clinical symptoms and signs that may suggest malignant degeneration, as previously discussed.

CONCLUSIONS:

Osteochondromas are typically resected only if symptomatic, causing functional impairment, for cosmetic reasons or due to malignant transformation.

The complication associated with HME to be most wary about is that of malignant degeneration, a risk ranging from 1-2% in those patients less than 21 years old, to 20 %, with increasing age. The risk of developing a chondrosarcoma in HME is higher for those osteochondromas situated near the pelvis, scapula, proximal humerus, proximal femur and spine.

CLINICAL PEARLS:

Development of a chondrosarcoma originating from an osteochondroma associated with HME may be suggested if the patient or clinician notes an increase in the size of the lesion on physical examination or if the patient develops pain in this region affected by the osteochondroma.

ACKNOWLEDGEMENTS:

The author would like to extend her thanks to Dr Isoline Rey DC who provided the case, and to Dr Timothy Mick DC, DACBR, FICC for proof reading the final text.

References

1. Pikula JR; Hereditary multiple exostosis: a case report, J Can Chiropr Assoc, 1996; 40(1)
2. Judith VMG Bovée; Multiple osteochondromas, Orphanet J Rare Dis. 2008; 3: 3.
3. Jones KB and Morcuende JA; Of Hedgehogs and Hereditary Bone Tumors: Re-Examination of the Pathogenesis of Osteochondromas, Iowa Orthop J. 2003; 23: 87–95
4. Han IH and Kuh SU; Cervical Osteochondroma Presenting as Brown-Sequard Syndrome in a Child with Hereditary Multiple Exostosis, J Korean Neurosurg Soc. 2009 May; 45(5): 309–311.
5. Chadha M and Singh A; Secondary chondrosarcoma of the cuboid bone in a patient with multiple exostoses Can J Surg. 2008 February; 51(1): E5–E6.

Further reading:
Taylor J, Hughes T and Resnick D (2010); Skeletal Imaging: Atlas of the Spine and Extremities, 2nd edition, Elsevier, USA http://www.radiologyteacher.com/index.cgi?&nav=view&DatID=688