0
Special Feature |

Pathological Case of the Month FREE

[+] Author Affiliations

Section Editor: Enid Gilbert-barness, MD


Arch Pediatr Adolesc Med. 2000;154(11):1163. doi:.
Text Size: A A A
Published online

DIAGNOSIS AND DISCUSSION: OSTEOCHONDROMA (EXOSTOSIS)

Figure 1. Clinical deformity of the forefoot with splaying and displacement of the toes.

Figure 2. Plain x-ray films show a bony outgrowth arising from the metaphysis of the proximal phalanx of the toe and growing away from the adjacent joint.

Figure 3. Gross appearance: a broad-based lesion covered with a cauliflower-shaped cartilaginous cap.

Figure 4. Histological findings: bony trabeculae with mature osteoblasts and osteoclasts and cartilage with mature lacunar chondrocytes arranged in rows or clusters (hematoxylin-eosin, original magnification ×250).

Osteochondroma is the most common benign primary tumor of bone.1 It has been reported in every bone in the body that develops by enchondral ossification.2 The sites affected most in descending order of frequency are the distal femur, the proximal tibia, the proximal humerus, the scapulae, pelvis, clavicles, and vertebrae.3 In the foot osteochondroma is commonly located in the phalanges and metatarsal bones.4 A particularly common site is the distal phalanx of the toe where it is a subungual exostosis.5,6 Most such cases involve the great toe. Other locations such as the talus and calcaneus have also been reported though less frequently.4,7,8

It is unclear whether osteochondroma is a true neoplasm or an aberration of development in endochondral bone formation. Uncertainty exists regarding the timing of its first appearance, whether it is congenital or evolves sometime later in life. Eighty percent of cases are diagnosed before age 21 years.2 Plain radiographs are usually diagnostic and no further workup is necessary.1 Differential diagnosis should include periosteal and parosteal osteogenic sarcoma.3

Osteochondroma is present in 2 distinct forms: (1) the solitary lesion occurring sporadically and (2) the hereditary familial osteochondromatosis transmitted to half the offspring and characterized by a single individual affected by numerous lesions throughout the skeleton that may cause severe deformities and growth disturbances of the bones.13 A third type of entity also exists: postradiation osteochondroma. The lesions occur in 12% of children with irradiated malignant neoplasms at the edges of the treatment fields.3 Osteochondroma in the long bones is a metaphyseal lesion arising from the cortex near the epiphyseal plate junction. It tends to grow away from the adjacent joint. It macroscopically consists of a mushroom-shaped bony outgrowth with a broad base that is either sessile or pedunculated and covered by a cartilage cap with a cauliflower appearance. The marrow cavity of the osteochondroma is continuous with that of the normal bone. Microscopy reveals mature cancellous (trabecular) bone in which foci of endochondral ossification may be observed.13 The cap is made of hyaline cartilage with mature lacunar chondrocytes often arranged in rows or clusters.1,2

Spontaneous regression is rare but has been reported.3 Malignant transformation may take place with a risk of 1% to 2% for solitary lesions and 5% to 25% for multiple lesions.1 Proximal lesions located in the axial skeleton and pelvic and shoulder girdles are at higher risk than average.1 The tumor has a tendency of turning into a low-grade chondrosarcoma but may also develop into an osteogenic sarcoma or a fibrosarcoma in rare cases.3 The osteochondroma grows in size until maturity and remains static throughout adulthood.1 It may be asymptomatic unless it disturbs the surrounding soft tissues such as tendons, nerves, and blood vessels. It can therefore cause tendinitis or bursitis, neural entrapment syndromes, and pseudoaneurysms.3,9

Asymptomatic quiescent lesions require no treatment. Those that are disturbing or suspected to be malignant (due to either rapid growth or sudden onset of pain) should be surgically removed by simple resection. The periosteum covering the lesion should be excised as well to avoid recurrence.1,3 The prognosis is excellent for isolated lesions and depends on the number and location of lesions, the degree and severity of joint and bone deformities, and malignant transformation in the familial type.13

Dee  RHurst  LCGruber  MAKottmeier  SA Principles of Orthopaedic Practice. 2nd ed. New York, NY McGraw Hill1997;262
Cotran  RSKumar  VRobbins  SL Robbins' Pathologic Basis of Disease.  Philadelphia, Pa2nd ed. WB Saunders Co1979;14821505
Eideken  JDalinka  MKarasick  D Roentgen Diagnosis of Diseases of Bone.  Baltimore, Md4th ed. Williams & Wilkins1990;94- 110
Fuselier  COBinning  TKushner  D  et al.  Solitary osteochondroma of the foot. J Foot Surg. 1984;233- 24
Fikry  TDkhissi  MHarfaoui  A  et al.  Subungual exostoses. Acta Orthop Belg. 1998;6435- 40
De Palm  LGigante  ASpecchia  N Subungual exostosis of the foot. Foot Ankle Int. 1996;17758- 763
Sella  EJChrostowski  JH Calcaneal osteochondromas. Orthopedics. 1995;85301- 305
Chioros  PGFrankel  SLSidlow  CJ Unusual osteochondroma of the foot and ankle. J Foot Surg. 1987;26407- 411
Israels  S JDowns  AR Traumatic aneurysm of the popliteal artery due to an osteochondroma of the femur. Can J Surg. 1980;23270- 272

Tables

References

Dee  RHurst  LCGruber  MAKottmeier  SA Principles of Orthopaedic Practice. 2nd ed. New York, NY McGraw Hill1997;262
Cotran  RSKumar  VRobbins  SL Robbins' Pathologic Basis of Disease.  Philadelphia, Pa2nd ed. WB Saunders Co1979;14821505
Eideken  JDalinka  MKarasick  D Roentgen Diagnosis of Diseases of Bone.  Baltimore, Md4th ed. Williams & Wilkins1990;94- 110
Fuselier  COBinning  TKushner  D  et al.  Solitary osteochondroma of the foot. J Foot Surg. 1984;233- 24
Fikry  TDkhissi  MHarfaoui  A  et al.  Subungual exostoses. Acta Orthop Belg. 1998;6435- 40
De Palm  LGigante  ASpecchia  N Subungual exostosis of the foot. Foot Ankle Int. 1996;17758- 763
Sella  EJChrostowski  JH Calcaneal osteochondromas. Orthopedics. 1995;85301- 305
Chioros  PGFrankel  SLSidlow  CJ Unusual osteochondroma of the foot and ankle. J Foot Surg. 1987;26407- 411
Israels  S JDowns  AR Traumatic aneurysm of the popliteal artery due to an osteochondroma of the femur. Can J Surg. 1980;23270- 272

Correspondence

CME
Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).
Submit a Comment

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Web of Science® Times Cited: 1

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Topics