Clear Cell Chondrosarcoma Mimicking Benign Bone Tumors / 대한정형외과학회잡지

ABSTRACT

PURPOSE: Clear cell chondrosarcoma may have a benign appearance even on a magnetic resonance imaging (MRI). Hence, it can be confused with benign bone tumors, such as a giant cell tumor or chondroblastoma. The aim of our study was to document the doctorassociated diagnostic errors in patients with clear cell chondrosarcoma and oncologic outcomes of these lesions, which were misdiagnosed as benign bone tumors. MATERIALS AND METHODS: We identified 10 patients who were diagnosed with and treated for clear cell chondrosarcoma between January 1996 and December 2014. One patient was excluded due to insufficient clinical data. We then reviewed their data regarding age, gender, symptom onset, tumor location, initial imaging diagnosis, and associated previous treatment. We examined the errors of surgeons and pathologists with respect to patient and tumor characteristics. We also analyzed treatment delay, time to local recurrence, metastasis, follow-up duration, and the oncologic outcome. RESULTS: The initial presumptive diagnosis based on MRIs for all 9 patients was benign bone tumor. Among 8 patients who underwent inappropriate procedure, half of them were diagnosed as clear cell chondrosarcoma immediately after the curettage. As for the remaining 4 patients, the surgeon did not send any tissue samples to a pathologist for a definite diagnosis in three patients and a pathologist made an incorrect diagnosis in one patient. We performed an appropriate surgery on all patients with a wide surgical margin. The average treatment delay was 27 months (range, 0–127 months), and the average follow-up duration was 65 months (range, 13–164 months). One patient had local recurrence after 12 months. Metastatic disease developed in 2 patients with a median time to definitive treatment of 24 months (12–37 months). Ten-year overall survival of patients with clear cell chondrosarcoma was 78%, and two patients died due to disease progression. CONCLUSION: Misdiagnosis of clear cell chondrosacroma as a benign bone tumor is not uncommon, even for experienced orthopaedic oncologists, resulting in definite curative surgery without biopsy. An inappropriate primary treatment may increase the risk of local recurrence and metastasis. Therefore, a proper subsequent surgery is mandatory for patients with clear cell chondrosarcoma who received inadvertent curettage.