Chondroblastoma

A fatal case of pure metaphyseal chondroblastoma

The chondroblastoma (CB) is a rare cartilaginous tumour; it represents less than 1% of all bone tumours. It is mostly localised at the level of the epiphysis of long bones. We report a fatal case of pure metaphyseal CB of the tibia in a 9-year-old boy whose pulmonary metastases developed soon after operative therapy of the primary tumour.

Metaphyseal and diaphyseal chondroblastomas

OBJECTIVE

Epiphyseal/apophyseal locations are important diagnostic radiological features of chondroblastomas (CB). Although the tumor may secondarily involve the metaphysis, reports of primary metaphyseal or diaphyseal CB without any epiphyseal or apophyseal involvement are exceptionally rare and frequently present as a diagnostic dilemma. The purpose of this study was to present seven cases of pure metaphyseal and/or diaphyseal CB along with a review of pertinent literature.

METHODS

A retrospective review of databases at two major referral centers revealed 390 cases of CB between 1960 and 2009. Out of these, seven histologically proven CB cases (1.8%) were found to be radiologically located in metaphysis and/or diaphysis, without involving the epiphysis and/or apophysis, and formed the study cohort.

RESULTS

There were four males and three females (age range 2-25 years). Locations included proximal femur (n = 1), distal femur (2), proximal humerus (2), clavicle (1), and proximal radius (1). All lesions showed marginal sclerosis. A periosteal reaction was seen in five cases (71%), cortical expansion in four cases (57%), and chondroid matrix in four cases (57%). A CT (two cases) demonstrated a matrix in both cases. An MR (one case) showed extensive perilesional edema. Bone scan (one case) showed intense uptake.

CONCLUSION

Pure metaphyseal and/or diaphyseal CB are exceedingly rare. A presumptive diagnosis may be considered in the appropriate age group in the presence of chondroid matrix, perilesional edema, periosteal reaction, and marginal sclerosis. Regardless of all the diagnostic possibilities, biopsy may still be required. However, knowledge of this entity will help make the final diagnosis and guide the correct treatment.

Chondroblastoma: an unusual cause of knee pain in the adolescent

Chondroblastoma is a rare, benign bone tumor that may mimic an orthopedic infection. Characteristic clinical features include specific radiographic findings, predilection for the adolescent age group, and long bone epiphyseal involvement. This case of chondroblastoma is unusual because of aggressive findings on radiographic studies which underscore the need to obtain hip radiographs on adolescent patients with knee pain.