CASE 102

By: Dr. Aliya Sarhan Al Barwani

HISTORY: 13 years old with knee pain for 6 weeks.

What are the findings?

Differential diagnosis?

How we treat this lesion?

FINDINGS:

AP radiograph of the right knee: There is a small well defined eccentric lucent lesion in the lateral femoral epiphysis of the medial femoral condyle with adjacent area of decrease bone density.

MRI sagittal and coronal T2/FS: The corresponding lesion is heterogeneous in signal with florid marrow edema. Mild joint effusion. Post contrast study shows avid enhancement with extensive marrow edema with sclerotic rim.

DIFFERENTIAL DIAGNOSIS:

·        Chondroblastoma.

·        Osteomyelitis.

·        Intra-osseous ganglion cyst.

·        Osteochondral defect.

Treatment: is curettage and packing or by Radiofrequency ablation.

DIAGNOSIS:

Chondroblastoma.

PEARLS AND DISCUSSION:

Chondroblastoma is a rare benign bony lesion, commonly seen in skeletally immature patients below 20 years. It is an eccentric epiphyseal lesion or apophyseal or epiphyseal bone equivalent lesion (can be seen in the patella and greater trochanter).

It commonly has marrow edema disproportion to the size of the Lytic lesion and 40 to 60% may present with calcification. A lobulated and thin sclerotic rim may be seen. It is treated by curettage and packing or RF ablation. The recurrence rate is high and follow up is advised if patient experience pain after treatment.

FURTHER READING

1.      Sailhan F, Chotel F. Chondroblastoma of bone in a pediatric population. J Bone Joint Surg Am. (2009)

2.      See comment in PubMed Commons belowBlancas C, Llauger J. Imaging findings in chondroblastoma. Radiologia. (2008)

3.      Amrami KK. Chondroblastoma of the hands and feet. Skeletal Radiology. (2004)

4.      Jaovisidha S, Siriapisith R. Radiological findings in 31 patients with chondroblastoma in tubular and non-tubular bones. Singapore Med J. (2013)

5.      Jaovisidha S, Siriapisith R. Radiological evaluation of chondroblastoma. Radiology. (1981)