Active aneurysmal bone cysts in children: possible evolution after biopsy

Purpose

The active or aggressive character in certain localisations of aneurysmal bone cysts in children requires either curettage with a considerable recurrence rate or a radical segmental excision, raising complex reconstructive challenges. Cyst maturation with subsequent ossification may be observed either spontaneously or after incisional biopsy.

Patients

Five new cases of active aneurysmal bone cysts (ABCs) with healing of the cyst after biopsy alone are reported. All patients had no treatment of the cyst after the biopsy.

Results

In two cases, the lesion initially increases in size immediately after the biopsy, and it is only secondarily that the lesion decreases in size. Four out of five cases of the spontaneous healing occurred in pelvic bone. The cysts healed after, respectively, 36, 24, 12, 32 and 12 months.

Conclusions

The emergence of these new cases of spontaneous healing encourages promoting clinical and radiological supervision after biopsy in selected cases. Unfortunately, it is impossible to predict a possible aggressive behaviour in ABCs. Then, if the lesion is quickly aggressive with clinically and radiologically increasing size after biopsy, it would be illogical and dangerous to let this ABC evolve. It would be necessary to treat it without delay. On the other hand, if the lesion moderately increased after the biopsy, it is possible to wait and observe the patient during a period of 5 months for a possible healing, if the ABC localisation is not dangerous. Of course, if the lesion does not increase in size after biopsy, there is no delay to treat it.     

Surgical treatment and recurrence rate of aneurysmal bone cysts in children

High recurrence rates have been reported after surgical treatment of aneurysmal bone cysts, ranging from 10-59%, and greater (five of seven) in children younger than 10 years. No previous study has focused specifically on recurrence as a function of age in a large pediatric study. The purpose of the current study was to review the outcome of current surgical techniques in the treatment of primary aneurysmal bone cysts in children and to determine if recurrence rates were higher in younger children, as proposed by some authors. This study included 45 children with primary aneurysmal bone cysts with more than 2 years followup after their first treatment using our current four-step surgical technique. The subjects were studied and classified on the basis of their age group (< or = 10 years of age or >10 years of age). The recurrence rate, and other parameters were determined after surgical treatment. Of the 45 children with primary aneurysmal bone cysts, 13 children were 10 years or younger and 32 were older than 10 years. Persistence or recurrence of the lesion requiring additional surgery occurred in three children in the younger age group and in five children in the older age group. The difference in persistence or recurrence rates based on age was not statistically significant. However, the persistence or recurrence rates are lower than previously reported (82% overall success rate after initial surgery).     

Unicameral and aneurysmal bone cysts

One hundred and seventy-eight cases of unicameral bone cysts (UBC) treated with curettage and bone grafting were compared to 141 cases treated with cortisone injections. The end results were comparable in the two groups. Local recurrence risk factors in the surgical group were active cyst and previous operations. In the other group they were multilocation of the cyst, active cyst, and size of cyst. A new radiographic classification of aneurysmal bone cyst (ABC) is proposed in a report of 198 cases of ABC. The treatment of choice in ABC is surgical and the type (curettage, curettage plus phenole or cryosurgery, resection or hemiresection) is selected on the basis of the radiographic aspect and the rate of growth of the cyst. Radiotherapy is only indicated in inoperable ABC cases.     

Juxtaphyseal aneurysmal bone cysts.

Aneurysmal bone cysts are benign primary or secondary lesions that commonly arise in long bones and often before skeletal maturity. Little has been written about aneurysmal bone cysts that abut the physeal plate. The records of 15 patients with juxtaphyseal aneurysmal bone cysts were reviewed. Fourteen of the patients were referred with abnormal radiographs after evaluation for pain in the affected limb. One patient presented with abnormal radiographs after fracture about the aneurysmal bone cyst. None of the patients had evidence of growth plate disruption. The children's ages ranged from 2 to 14 years, with a mean of 9.8 years. There were 10 boys and five girls. Lesion locations included: six in the proximal tibia, three in the distal fibula, two in the distal tibia, two in the proximal femur, one in the distal femur, and one in the distal radius. All of the lesions abutted the physeal plate and fell into one of the types in Campanacci's classification of juxtaphyseal aneurysmal bone cysts. Three lesions were classified as Type 1, eight were Type 2, and four were Type 3. This study included no cases of Type 4 or 5 lesions. Treatment of all lesions consisted of excision, curettage, and bone grafting with care taken to preserve the growth plate. Adjunctive cauterization was performed in two cases. There were no incidences of postoperative physeal plate arrest. Overgrowth of the fibula occurred in one patient. Three patients experienced recurrent lesions. One of the children underwent repeat curettage and bone grafting with no additional recurrence. In the other two children with recurrence, the lesion had grown away from the physeal plate while remaining static in size and asymptomatic. Based on this study, juxtaphyseal aneurysmal bone cysts may be treated satisfactorily with intralesional surgery and bone grafting with expectation of normal physeal growth.     

Treatment of aneurysmal bone cysts with saucerization and bone marrow injection in children.

In four consecutive children, healing of large, active aneurysmal cysts of the long bones was achieved with saucerization, closure of the periosteum, and instillation of autologous bone marrow into the cavity. The saucerization procedure consisted of excision of the subperiosteal new bone with its attached cyst contents and curettage of the remaining cortical bone. A centripetal pattern of bone healing was observed in which an ossification front advanced from the periphery to the center of the cavity. We conclude that autologous bone marrow injections are a simple means of augmenting the healing of aneurysmal cysts of long bones treated with saucerization. The procedure avoids the morbidity and costs associated with alternative methods of bone grafting.     

Treatment of aneurysmal bone cysts in childhood

Twenty-five aneurysmal bone cysts were treated by curettage, saucerization, or resection. Healing occurred in all cysts of the long bones that were treated by saucerization and bone grafting or by resection and bone grafting. However, healing occurred in only half of the cysts of the long bones that were treated by curettage and bone grafting. In contrast, removal of the soft tissue contents from cysts of the pelvis, without curettage of bone or bone grafting, was sufficient to initiate healing. Although there was an apparent difference in the behavior of cysts of the long bones and pelvis, it is likely that the essential component of treatment at both sites is to remove the vascular soft tissue from the cyst.     

Selective arterial embolisation in aneurysmal bone cysts

Summary The treatment of three cases of aneurysmal bone cyst by selective arterial embolism is described. Two cases had involvement of the pelvis and one of the knee. The 2-year follow up has been promising. Radiologically the lesion has been arrested with increased density of the cyst wall and intra-cystic trabecular new bone formation. Pain relief has been complete and up to now no surgical treatment has been required.

---

Résumé Présentation de l'évolution clinique et radiologique de trois cas de kyste osseux anévrysmal, deux localisés au bassin et le troisième au genou, traités par embolisation artérielle sélective. Les résultats, avec 2 ans de recul, sont encourageants. Radiologiquement la lésion paraît stabilisée avec densification des parois et apparition de travées d'os nouveau à l'intérieur du kyste. Les douleurs ont complétement disparu et jusqu'à présent aucun geste chirurgical n'a été nécessaire.

     

Current treatments of primary aneurysmal bone cysts

The management of aneurysmal bone cyst depends on the age of the patient, the location, extent, aggressiveness and the size of the lesion. In the light of their experience and a review of the literature of 1256 aneurysmal bone cysts, the authors analyzed various treatment modalities. Inactive lesions can heal with biopsy or curettage alone. In active or aggressive lesions, elective treatment usually consists of curettage, whether associated or not with bone grafting and local adjuvants. Aneurysmal bone cyst in young children do not seem more aggressive than in older children. In pelvic locations, the emergence of a few cases of spontaneous healing (even in active or aggressive lesions) encourages the adoption of clinical and radiological supervision for some months after biopsy when possible. In some cases, the localization and extent of the cyst are such that operative treatment is extremely hazardous. Selective arterial embolization has made a considerable contribution towards the therapeutic solution of such cases. For some authors, direct percutaneous Ethibloc injection can be recommended as the first-choice treatment except in spinal lesions. Nevertheless, the complications encountered in some series after percutaneous embolization of aneurysmal bone cyst with Ethibloc should encourage the use of Ethibloc injection not as an initial treatment but as a reliable alternative to surgery.     

Bisphosphonate therapy for spinal aneurysmal bone cysts

Purpose

To assess the efficacy of bisphosphonate therapy in the management of spinal aneurysmal bone cysts (ABCs).

Methods

A prospective study of six consecutive patients aged between 7 and 22 years with spinal ABCs treated with pamidronate (1 mg/kg) or zoledronate (4 mg). A visual analogue scale (VAS) for pain and radiological (contrast-enhanced MRI and CT scan at 3 and 6 months, then yearly X-rays) follow-up was continued for a minimum of 6 years.

Results

One patient with an unstable C2/3 failed to respond to a single dose of bisphosphonate and required surgical resection and stabilisation with autologous bone grafting. Another, with a thoraco-lumbar ABC, experienced progression of neurological dysfunction after one cycle of bisphosphonate and, therefore, required surgical resection and stabilisation. In all other patients pain progressively improved and was resolved after two to four cycles (VAS 7.3–0). These patients all showed reduction in peri-lesional oedema and increased ossification by 3 months. No patients have had a recurrence within the timeframe of this study.

Conclusions

Bisphosphonate therapy can be used as the definitive treatment of spinal ABCs, except in patients with instability or progressive neurology, where surgical intervention is required. Clinicians should expect a patients symptoms to rapidly improve, their bone oedema to resolve by 3 months and their lesion to partially or completely ossify by 6–12 months.

     

Epidemiology of aneurysmal bone cyst in children: a multicenter study and literature review

The purpose of this study was to review the demographic data of children and adolescents with aneurysmal bone cysts (ABCs). The authors performed a retrospective, multicenter, pediatric population-based analysis of 156 patients with primary ABCs. Only patients with histologic confirmation of the diagnosis were included. A review of French and English literature of 255 children and adolescents was included regarding sex, location of the lesion and age at diagnosis. There were 212 boys and 199 girls with a median age at diagnosis of 10.2 years (range, 1.5-17 years). Forty-four patients were under 5 years of age; 111 patients were between 5 and 10 years of age, and 139 were older than 10 years of age. The femur, tibia, spine, humerus, pelvis and fibula were the most common locations. In 256 cases (62.7%), ABCs occurred in long bones. We also studied the data and location of 161 ABCs of the mobile spine (13 cases from our series and 148 from the literature review). There were 48 ABCs in the cervical spine, 48 in the thoracic spine, and 65 in the lumbar spine. We found no main differences in site distribution and sex, between the children and the general population.     

Induced healing of aneurysmal bone cysts by demineralized bone particles

Two cases of induced healing of aneurysmal bone cyst (ABC) following intralesional implantation of a bone paste made of autogeneic bone marrow and allogeneic bone powder are reported. The calcaneum in one case and the superior pubic ramus in the other were blown out by an ABC and would have required extensive surgery. Via a minimal exposure, the cyst was partially evacuated and filled with an admixture of a partially demineralized bone particles with bone marrow. Ossification of the peripheral shell was the first sign of healing and was observed within the first 3 postoperative months. Successful healing was observed in both cases. The rationale underlying this intralesional treatment was that the bone grafting material might reverse ABC expansion by promoting ossification through a bone induction mechanism. The concept of this treatment was to retain the ABC tissue, using its own intrinsic osteogenic potential to promote healing. By triggering intralesional new bone formation, the bone paste represented an effective means to reverse the expanding phase of ABC. The particulated bone allograft was easy to handle and to introduced in an irregular cavity. Moreover, as a complete cyst evacuation was not required, a minimal surgical approach could be used so that the risks and morbidity associated with an extensive approach were reduced. Its use is of particular interest in poorly accessible areas like the pelvis and spine.     

Sclerotherapy with polidocanol for treatment of aneurysmal bone cysts

Background and purpose Recent data suggest that percutaneous sclerotherapy is a safe alternative to surgery for treatment of aneurysmal bone cysts (ABCs). We present our experience of this method.

Methods We retrospectively analyzed data from 38 consecutive patients treated with repeated injections of polidocanol. Each injection consisted of 2–4 mg polidocanol per kg body weight. Radiological and clinical assessments were performed until healing.

Results All cycts except 1 healed after a median of 4 (1–11) injections. A lesion failed to heal in 1 patient, who was operated. 3 patients experienced minor local inflammatory reactions.

Interpretation Our results show that percutaneus sclerotherapy with polidocanol has high efficacy in the treatment of ABCs, with a low frequency of side effects. Our findings corroborate data presented in previous publications. We believe that the method will be especially valuable in ABCs of the pelvis and sacrum, where surgery is associated with considerable morbidity.     

Multiple soft tissue aneurysmal cysts: An occurrence after resection of primary aneurysmal bone cyst of fibula

We report a case of multiple extraosseous aneurysmal cysts occurring in the muscle and subcutaneous plane of postero-lateral aspects of the upper right leg. They appeared about 15 months after resection of aneurysmal bone cyst of the upper end of the fibula. They varied in size from 2 cm to 5 cm. Radiologically they were well-defined lesions with central septate areas surrounded by a rim of calcification. Histologically they showed central cystic spaces separated by septa consisting of fibroblasts, osteoclast type of giant cells and reactive woven bone. Thus they showed histological similarity with aneurysmal bone cysts, but did not show any connection with the bone. Only very few examples of aneurysmal cysts of soft tissue had been described in the past one decade and they were reported in various locations including rare sites such as arterial wall and larynx. Recent cytogenetic analyses have shown abnormalities involving 17p11-13 and/or 16q22 in both osseous and extraosseous aneurysmal cysts indicating its probable neoplastic nature. Our case had unique features like multiplicity and occurrence after resection of primary aneurysmal bone cyst of the underlying bone.     

Percutaneous Ethibloc injection in the treatment of primary aneurysmal bone cysts

The effects of percutaneous Ethibloc (Ethicon/Johnson & Johnson, St-Stevens-Woluwe, Belgium) injection into primary aneurysmal bone cysts were analysed. Two patients with a venous drainage after injection of a medium contrast were excluded. Twelve patients underwent at least one percutaneous injection of Ethibloc. The average follow-up period was 5.1 years. At final follow-up, six patients had complete healing of the cyst, three had partial healing and three, who had no response, were treated by curettage and bone grafting. Complete healing was observed for all the aggressive lesions. No major complications were noted. Ethibloc injection may be performed as a primary treatment of aneurysmal bone cysts if the technique is followed with precision.     

Treatment of aneurysmal bone cysts by introduction of demineralized bone and autogenous bone marrow

BACKGROUND: On the assumption that an aneurysmal bone cyst has an intrinsic potential to heal by ossification, a new, minimally invasive protocol was developed. Demineralized bone powder mixed with bone-marrow aspirate was introduced into the cyst to halt the expansion phase and to allow the cyst to ossify. We hypothesized that, in order to induce bone-healing, cells from the cyst are needed to respond to the inductive material but that curettage or extensive surgery is not necessary. The goals of the present study were to assess cyst-healing and to determine the prevalence of recurrence associated with this new procedure. METHODS: Thirteen biopsy-proven primary aneurysmal bone cysts were entered through a small incision, and a paste of demineralized bone and autologous bone marrow was introduced with an applicator. The study group included three male and ten female patients with a mean age of 16.6 years. The cyst was located in a long bone in six patients, the pelvis in five patients, and the scapular glenoid and the calcaneus in one patient each. Five patients had not received treatment previously, whereas one had had a preoperative embolization and seven had recurrent lesions that had been treated previously. RESULTS: After a mean duration of follow-up of 3.9 years, healing was achieved in eleven patients. CONCLUSIONS: This minimally invasive method is able to promote the self-healing of a primary aneurysmal bone cyst. As no curettage is required, the proposed treatment avoids extensive surgery and blood loss and is convenient for the treatment of poorly accessible lesions such as those occurring in the pelvis. LEVEL OF EVIDENCE: Therapeutic Level IV.