Treatment and differential diagnosis of aneurysmal bone cyst based on our own experience.

BACKGROUND: Aneurysmal bone cyst was first described by Jaffe and Lichtenstein in 1942. Schajowicz in 1972 in his Histopathological Classification of Primary Bone Tumors (later modified by WHO in 1993) placed it in group IX - tumor-like lesions. Its etiology and pathogenesis is not completely clear. Aneurysmal bone cysts are usually found in older children and young adults, rarely before the age of 5 or after 30. The aim of the study is to evaluate aneurysmal cyst treatment outcomes in patients we have treated and present diagnostic difficulties, especially considering the giant cell tumor in differential diagnosis.

MATERIAL AND METHODS: The study group consisted of 40 patients aged from 10 to 65 years (mean age 22 years), including 21 men and 19 women, who underwent surgery at the Bone Tumor and Neoplasm Unit between 1999 and 2006. The follow-up period varied from 2 to 78 months (mean 23 months).

RESULTS: A single surgical procedure was performed in 25 patients. No recurrences were noted in this group. In the remaining 15 cases, the tumor relapsed between 2 and 72 months after surgery (mean 17 months). In 12 patients, the histopathological examination was inconclusive. The giant cell tumor of bone was considered as a second diagnosis in all these cases.

CONCLUSIONS: 1. Surgical treatment of aneurysmal bone cysts enables radical excision of the lesion with same-time histopathological verification. 2. The basis of effective treatment of primary and recurring aneurysmal bone cysts consists in complete resection of all tissues lining the cyst and any of its components from the surrounding soft tissues. 3. An effective plan of surgical treatment of aneurysmal bone cyst aimed at reducing the risk of tumor recurrence relies crucially on precise determination of its size, characteristics and topography via imaging workup. 4. Relapses are most common in patients suffering from the aggressive or active form of aneurysmal bone cyst. 5. Tumor location in direct proximity of a joint and the presence of epiphyseal cartilage hinders complete resection of the lesion and gives rise to technical problems during surgery. 6. The diagnosis of aneurysmal bone cyst most often leads physicians to assume the presence of giant cell tumor. If this diagnosis is confirmed following surgery, the patient should be subjected to additional radiotherapy. 7. Patients suffering from aneurysmal bone cyst require a ling follow-up due to the possibility of late recurrence of the tumor.