CHONDROBLASTOMA IN CHILDREN: THE SO.F.O.P. MULTICENTRIC SERIES

Abstract

Purpose of the study: Chondroblastoma is a rare benign cartilage tumor usually observed in secondary ossification centers of long bone in subjects aged 10 to 20 years. We report a multicentric series of 63 cases of chondro-blastoma in children and attempt to identify particular pediatric epidemiological features and identify factors of risk of recurrence.

Material and methods: Clinical data an pre and postoperative imaging were analyzed as well as the histological findings reported by one observer. Files were collected from ten pediatric orthopedic units in France (two in Lyon, three in Paris, Rennes, Strasbourg, Toulouse, Saint-Etienne, Nice). Data were stored in a single database. The series included 35 boys, and 29 girls (sex ratio 1.25=. Mean age at diagnosis was 12 years (18 months to 17 years), 13 years for boys and 11 years for girls. Tumors were located in the epiphysis of the proximal tibia (n=17), the proximal femur (n=16), proximal the humerus (n=16), the distal femur (n=4), tarsal bones (n=4), the distal tibia (n=2), the fibula (n=2), the pelvis (n=1) and the distal radius (n=1). Preoperatively, the Springfield classification was: latent (n=14), active (n=36), aggressive (n=8); five tumors could not be classified. Treatment consisted in curettage-graft (n=40), curettage alone (n=17), curettage and cement filling (n=3), en bloc resection with reconstruction (n=3). Adjuvant alcoholization was used in one case. The histological study searched for an aneurysmal component within the tumor. Four patients were lost to follow-up and 59 patients were analyzed with a mean follow-up of 53 months (range 1–162 months). Statistical tests were applied to the data set to search for factors of risk of recurrence.

Results and discussion: The inaugural syndrome was pain (n=52) or a palpable mass (n=3); the tumor was a fortuitous discovery in one case. Comparison with series including both children and adults revealed certain specific features of this pediatric series. The sex ratio was lower in our series; the distal femur localization, frequent in adults, was rare in children. AT one year, the rate of recurrence was 34% in our series (18/53). Fifteen of the 18 recurrences concerned radiologically active (n=12) or aggressive (n=3) tumors. Recurrence predominated in the tarsal bones (3/3), the proximal humerus (6/14), the proximal femur (5/13) and the proximal tibia (3/14). An aneurysmal component was found in 22% of the recurrent tumors and in 16% of those without recurrence. Statistical tests failed to distinguish any significant correlation with recurrence for age, gender, type of treatment, Springfield grade or localization.

Conclusion: The epidemiological data in this series of pediatric chondroblastoma showed features different from adults. The rate of recurrence was particularly high in this multicentric series (but not statistically significant) for localizations in the tarsal bones or a deep joint (with difficult access such as the shoulder and the hip) or with an aneurysmal component.