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Age / Sex : /
Age / Sex : 23/M
Chief complaint : Palpable abnormality in the posterior aspect of the right ankle. Limitation of motion of the right ankle (especially dorsiflexion)
What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case.
* Send Application Answers to Ja-Young Choi, MD ([email protected])
Courtesy : Hye Won Chung, MD./Seo Min Jeong, MD. Asan Medical Center
Diagnosis: osteochondroma
Discussion
Findings:
There is an osseous protuberance at the superior aspect of the calcaneal body on the lateral radiograph of right ankle. It shows medullary and cortical continuity between the lesion and parent bone on sagittal reformatted CT-images of the right ankle. Small bony protuberance is associated with this calcaneal mass at the adjacent talus.
Differential Diagnosis:
Bony spur Juxtacortical osteoma Juxtacortical osteosarcoma Periosteal chondroma Myositis Ossificans Soft tissue osteosarcoma
Diagnosis: Solitary osteochondroma, calcaneus.
Discussion:
Osteochondromas are cartilage-covered osseous excrescences that arise from the surface of a bone. They may be solitary or multiple or occur spontaneously or after accidental or iatrogenic injury or irradiation. It is the most common benign bone tumor and usually located in long bones at metaphyseal region. Osteochondroma is radiographically characterized by an osseous protuberance arising from the external surface of a bone and containing spongiosa and cortex that are continuous with those of the parent bone. Typically, lesions point away from the nearby joint and toward the diaphysis. CT can be used to evaluate osteochondroma and may be especially useful in demonstrating cortical and medullary continuity where the osseous anatomy is complex. The radiographic features of solitary osteochondromas are usually diagnostic and easily differentiated from other causes of osseous outgrowth, including osteoma, osteophyte, and enthesopathy, and from heterotopic ossification and parosteal osteosarcoma. Osteochondromas are uncommon in the foot, and when they do occur they tend to involve long bones or tufts of the phalanges as subungual exostoses. While small exophytic bone growths are common on the calcaneus, they are often improperly referred to as osteochondroma. Plantar and posterior heel spurs are traction spurs and not true osteochondromas. Solitary osteochondroma is usually asymptomatic. However, osteochondroma in tarsal bones may represent with variable symptoms, including pain, ankle swelling, painless mass, and a limited range of ankle motion. Pain is usually caused by pressure and friction against the nerves and bones resulting in possible nerve irritation or a block of joint motion. The imaging findings are similar as those in the other solitary osteochondromas.
References:
1. Resnick D, Kyriakos M, Greenway GD. In: Resnick D, Kransdorf MJ, 3rd ed. Bone and joint imaging. Philadelphia, Pen: Saunders, 2005;1120-1198.
2. Blitz NM, Lopez KT. Giant solitary osteochondroma of the inferior medial calcaneal tubercle: A case report and review of the literature. J Foot Ankle Surg 2008; 47:206-212.
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