[Aneurismal bone cyst in children: 17 cases].

Introduction: The aneurismal bone cyst (KOA) represents 1.5 to 4% of benign osseous tumors. It affects the young patients and its etiopathogeny is still discussed. Numerous difficulties of diagnostic, therapeutic and specially evolution, characterize this pathology.

Material And Methods: Our study reports 17 patients who were treated between 1976 and 2000. The average age was 8 years and delay of diagnostic was 11 months. It affected the long bones in 70%, the brief bones in 25% and the flat bones in 5%. In limbs, the pathological fracture was revealing in 47%, the painful lameness in 35% and tumefaction in 18% of cases. For two vertebral locations, pain was associated with a stiff neck for the cervical spine and there was a deformation with a medullar compression for the lumbar vertebral location. The radiological aspect was typical in 82% of cases. First biopsy in 13 cases allowed to confirm the KOA in eight cases; for five cases, a second biopsy was necessary to confirm diagnosis. In four cases, diagnosis was hold on typical radiographic aspect or on the hemorrhagic nature of the cyst. The surgery was realized in 15 cases (88%), with 13 eventrations and graft (three osteosynthesis) and two complete exeresis. The radiotherapy was performed for a hemorrhagic cyst located in cervical spine. Finally, a cast immobilization alone was realized for a location of the patella.

Results: A good result was observed in nine cases, the recurrence in three cases, degeneracy in one case and we deplore one death following a toxic shock. Degeneracy seems to be due to an initial misunderstanding of the osteosarcoma. Three patients could not be evaluated for the study.

Discussion: The KOA is a solitary bone dystrophy that can be primitive, or secondary to a sometimes-sly underlying hurt. The symptomatology is varied according to the location; modern imaging allows to better defining of the KOA aspects. Biopsy is indispensable for the diagnosis, but histological confirmation is not always certain. The best treatment must permit the "carcinologic" removal of the KOA. The reconstruction will be done by graft and osteosynthesis if necessary. The injection of ethibloc and the embolisation are indicated for the voluminous and very aggressive cysts. Radiotherapy, with its important morbidity, can be used for the inoperable cases. Unpredictable evolution remains threatened by the risk of local recurrence and later, by the risk of degeneracy.