Current Strategies for the Treatment of Aneurysmal Bone Cysts

Aneurysmal bone cyst of the calcaneus: A rare case report and review of the literature

INTRODUCTION AND IMPORTANCE

Aneurysmal bone cyst (ABC) is a benign lytic bone tumor of the skeletal system but locally destructive lesion of unknown origin. It often occurs in childhood and usually involves the metaphyseal region of long bones; thus, its localisation in the calcaneum remains rare; its atypical presentation in our case makes it remarkable.

CASE PRESENTATION

We describe a case of a young patient who suffered from chronic heel pain, in whom the clinical examination finds swelling and pain on palpation. A complete radiological assessment was carried out, which revealed a solitary and expansive osteolytic lesion within the calcaneus. Treatment included tumor curettage and reconstruction with allograft and cement. The biopsy report was consistent with an ABC. The postoperative follow-up at 18 months was marked by a good radio-clinical evolution and no recurrence.

CLINICAL DISCUSSION

ABCs are benign cystic expansive tumors that are reactive, locally destructive and blood-filled, their occurrence in the calcaneus has been reported in only 1.6 % of total reported cases. Talalgia is the most frequent sign associated with swelling. Liquid-liquid level images on MRI is a pathognomonic sign of these lesions but the gold standard diagnosis remains histology. Their treatment is based on curettage - filling by grafting.

CONCLUSION

Curettage combined graft makes results butter and improves the quality of life.

Response of Recurrent Aggressive Aneurysmal Bone Cyst of Distal Tibia to Denosumab Treatment

Introduction

Aneurysmal bone cysts (ABCs) are aggressive and benign tumors that primarily affect children and adolescents. The standard course of treatment for ABCs involves surgical excision or curettage with a bone transplant or cement to repair the deficiency. Denosumab, a monoclonal antibody that inhibits receptor activator of nuclear kappa B ligand, is used to treat osteoporosis, skeletal metastasis, and giant cell tumors of the bones.

Case Report

This case study details the therapeutic treatment of a female patient, age 22, who had a recurring aggressive ABC of the distal tibia. The patient was initially treated using curettage and lesion filling. However, recurrence of the osteolysis was observed 9 months later that led to subsequent interventions involving absolute alcohol sclerotherapy in multiple sessions. However, these interventions failed to achieve ossification. Following unsuccessful surgical and sclerotherapy treatments, the patient was administered denosumab, which led to a positive response. Regular radiographic and clinical follow-up demonstrated significant improvements in ossification and pain reduction. During the course of the 12-month treatment, the frequency of visits was gradually reduced. Further, follow-up and monitoring revealed the effectiveness of the local control and long-term treatment.

Conclusion

This case report highlights the ability of denosumab to manage recurrent aggressive ABCs after surgical or sclerotherapy failure.

Management of aggressive recurrent thoracic spine aneurysmal bone cyst in a 7-year-old male: A case report and review of the literature

Background

Spinal aneurysmal bone cysts (ABCs) are rare, histologically benign tumors with aggressive behavior, which may cause bone and soft-tissue destruction, particularly affecting neural elements. Management of these tumors, including treatment modalities and follow-up protocols, remains challenging.

Case Description

A 7-year-old boy presented with chest wall pain persisting for two months before admission, accompanied by progressive mono paresis lasting ten days before admission. Myelopathy signs were evident during the examination. Imaging confirmed a multicystic lesion at the T6 level involving the posterior elements of the vertebra, with significant cord compression. Due to deteriorating neurological function, he underwent urgent laminectomy and neural decompression, followed by subtotal tumor resection. Postoperative histopathological examination confirmed the diagnosis of an ABC, and the patient experienced significant neurological recovery. However, after 21 days, the patient was readmitted to the emergency department with severe paraparesis. Magnetic resonance imaging revealed rapid growth of the residual tumor, leading to cord compression. He underwent aggressive total tumor resection, T6 vertebral body corpectomy, and fixation with pedicle screws and cage insertion. Following the second surgery, prompt neurological recovery occurred.

Conclusion

This rare case report emphasizes the importance of a close follow-up protocol for spinal ABCs in the pediatric population. It highlights the challenges in managing these tumors and the need for vigilant monitoring to detect and address rapid recurrences.

Diagnosis and Current Treatment of Aneurysmal Bone Cysts

The purpose of this review is to increase awareness about the evolution and development of current trends in the diagnosis and treatment of aneurysmal bone cysts (ABCs). ABCs are benign, but locally aggressive bone tumors that mainly affect children. ABCs comprise 1% of all primary bone tumors and occur most frequently during the first two decades of life. The diagnosis is made using a variety of imaging modalities and has the characteristic features of an expansile, radiolucent lesion that is often seen in the metaphyseal region of the bone and has fluid-fluid levels that are apparent on MRI. In the pediatric population, telangiectatic osteosarcoma and unicameral bone cyst (UBC) are the main differential diagnoses of an ABC. Giant cell tumors (GCTs) also include in differential diagnosis, which often manifest in patients older than 15 and do not penetrate the open physis although they develop after the physeal closure. Imaging alone cannot rule out telangiectatic osteosarcoma; therefore, a biopsy is recommended. A variety of treatment options have been described; traditionally, most patients are treated with curettage and bone grafting. Curettage alone, however, usually results in tumor recurrence following excision. A variety of adjuvants have been utilized with varying degrees of effectiveness to reduce the risk of local recurrence. When a cyst is in the pelvis, its location and size are such that surgery is a very risky option. Selective arterial embolization has significantly contributed to the development of effective treatments for these situations. Embolization or radiation, as well as denosumab therapy, are widely used as therapies for ABCs in anatomic locations where surgery would significantly increase morbidity.

Treatment of Spinal Aneurysmal Bone Cyst with Percutaneous Injection of Hydroxyapatite Osteoconductive Cement

PURPOSE

The aim of this study was to evaluate treatment efficacy of percutaneous injection of hydroxyapatite-osteoconductive-cement in patients with spinal aneurysmal bone cysts.

MATERIALS AND METHODS

The study was designed as a retrospective observational clinical study. We included patients who were diagnosed with of spinal aneurysmal bone cyst, at our institution between 2013 and 2020, and treated with percutaneous injection of osteoconductive cement: "Cerament"® (BONESUPPORT AB, Lund, Sweden). Typical clinical and radiological features of the ABCs treatment and follow-up were investigated.

RESULTS

Our study included nine patients, two children and seven adults. Three different types of approaches were applied: (single pedicle approach in 3 patients; double pedicle approach in 2 patients; while in the remaining cases, a multiple access approach was used. VAS score decreased from 8.5 ± 0.5 before treatment to 4.1 ± 0.9 at 6-months-follow up. All of the patients reacted well to treatment, with none neurological complications, complete loss of pain and achieved osteosclerosis as radiological marker of treatment success.

CONCLUSION

Treatment of symptomatic spinal ABC's with hydroxyapatite cement is effective to achieve complete pain reduction and sclerosis.

Sclerotherapy as a primary or salvage procedure for aneurysmal bone cysts: A single-center experience

BACKGROUND

Aneurysmal bone cysts (ABC) are benign cystic bone tumors of an osteolytic and locally aggressive nature. As an alternative to the primary treatment of choice, which consists of curettage with bone grafting, alternative treatment methods with promising results have been described. At our department, we have, in recent years, used percutaneous sclerotherapy with polidocanol. The objective of this study was to identify the healing rate and safety of sclerotherapy with polidocanol.

AIM

To identify the efficacy and safety of sclerotherapy with polidocanol in primary and recurrent ABC.

METHODS

Twenty-two consecutive patients (median age 12.5 years; range 1-27) with 23 ABCs treated with sclerotherapy with polidocanol from 2016-2021 were included retrospectively. Eleven patients (48%) had undergone different forms of previous treatment with recurrence. Under general anesthesia and fluoroscopic guidance, repeated percutaneous injections of 4mg polidocanol/kg body weight were performed. Through review of the electronic medical records, the following were identified: healing and recurrence rate, number of treatments, gender, age, comorbidity, location of the tumor and side effects / complications, as well as any previous surgery for ABC. The median length of radiographic follow-up was 19.5 mo.

RESULTS

All ABCs except one (96%) showed healing or stable disease after a median of 4 (range 1-8) injections. Complete clinical and radiographic healing was observed in 16 cysts (70%), while partial radiographic healing with resolution of pain was seen in 6 cases (26%) and considered as stable disease. The cyst that failed to heal had previously undergone curettage twice with recurrence. One patient with a large pelvic ABC experienced, right after two injections, a sudden drop in blood pressure, which could quickly be reversed. One patient with a juxtaphyseal ABC in the femoral neck showed a minor limb length discrepancy because of deformity. Beyond that, no complications were observed.

CONCLUSION

Percutaneous sclerotherapy with polidocanol appears to be a safe alternative for treatment of aneurysmal bone cysts. In our series of both primary and recurrent cysts, it showed the ability to achieve healing or stable disease in 22 of 23 cases (96%). Further studies are needed to decide if this provides a long-lasting effect.

Endoscopic Assisted Caldwell-Luc Approach for Total Excision of an Extensive Aneurysmal Bony Cyst of the Maxillary Sinus

Aneurysmal bone cysts (ABCs) are uncommon lesions in head and neck area that could be primary or secondary in origin. The main problem with the traditional curettage and debridement is the high rates of recurrence, and cosmetic disfigurement with the open approach. In this article, we describe the use of a combined endoscopic sinus surgery and endoscopic assisted Caldwell approach to achieve a complete surgical excision of left maxillary sinus ABC extending to the left infratemporal fossa, and to avoid facial disfigurement in a 13-year-old female patient presented to our hospital with diplopia, facial pain, and headache. The patient had uneventful post-operative recovery period with resolution of the presenting symptoms with no complications. Hence, we recommend this combined endoscopic surgical approach in such cases.

Pseudocysts of the jaw: a retrospective study of 41 cases from a single institution

OBJECTIVE

The purpose of this retrospective study was to investigate and compare the clinical, radiographic, pathological, pathogenesis, and therapeutic features of simple bone cysts (SBCs) and aneurysmal bone cysts (ABCs) of the jaw.

METHODS

35 patients with SBCs and 6 patients with ABCs who received treatment at the Department of Oral and Maxillofacial Surgery, Zhejiang University School of Medicine from 2017 to 2022 were followed up and reviewed retrospectively.

RESULTS

The study included 41 patients, accounting for 2.14% of all jaw pathologies, with 35 patients having SBCs and 6 patients having ABCs; their average ages were 26.63 ± 13.62 years and 17.83 ± 7.88 years, respectively. The prevalence of SBC and ABC did not differ significantly by sex. The mandible was the most vulnerable area to be involved. Only 5.71% (2/35) of patients with SBCs and 16.7% (1/6) of patients with ABCs reported histories of previous trauma in the same region of the pseudocysts. A total of 42.86% (15/35) of SBC cases and 66.67% (4/6) of ABC cases had malocclusions. The radiographic features of pseudocysts varied in shape, were associated with the root, and unilocular or multilocular. All patients had curettage with or without bone graft or substitute implantation, and recurrences did not occur in 94.29% (33/35) of SBC patients and 100% (6/6) of ABC patients after a mean follow-up time of 26.23 ± 15.47 months and 21.67 ± 19.75 months, respectively.

CONCLUSIONS

Pseudocysts, including SBCs and ABCs, are benign osteolytic lesions without an epithelial lining that occur occasionally in the jaw, mostly in adolescents and young adults, and their incidence did not significantly differ by sex. The most vulnerable site of involvement is the mandible, and they are generally not overtly aggressive. Trauma has a less significant role in pseudocysts, but minor trauma, such as malocclusion, has the potential to influence pseudocyst development. The clinical presentation of pseudocysts lacks specificity, and most patients are asymptomatic and found incidentally during radiographs. Dental panoramic radiographs and CBCT cannot accurately distinguish between SBC and ABC, and the final diagnosis depends on pathological diagnosis. Curettage combined with bone grafting is currently the best treatment for both, with a 5.71% (2/35) recurrence rate for SBC and no recurrence found for ABC.

Vertebral Aneurysmal Bone Cyst Mimicking Osteosarcoma: Case Report and Review of the Literature

Aneurysmal bone cysts are benign osseous lesions containing blood-filled cavities separated by walls of connective tissue. They can be difficult to identify clinically due to similarities in presentation, imaging, and histology with other pathologies. Specifically, it is important to distinguish these benign lesions from malignant processes, as both surgical and medical management differ. We present the case of a 21-year-old patient who presented with impaired motor and sensory function in his lower extremities. Radiologic findings were concerning for an invasive neoplasm, and the intraoperative frozen section supported this conclusion. However, an additional histological investigation was confirmatory for a diagnosis of an aneurysmal bone cyst. The patient underwent corpectomy, laminectomy, and a posterior spinal fusion, and regained motor and sensory function shortly thereafter. This report details the importance of considering aneurysmal bone cysts in the differential of infiltrative bone lesions, despite their benign nature, as medical and surgical management can vary greatly.

Treatment of bone cysts by percutaneous injection of demineralized bone matrix mixed with bone marrow

Bone cysts whether aneurysmal or simple, are known for their tendency to recur. To replace the classical aggressive surgeries, minimally invasive techniques were developed giving differing results based on variable radiographic criteria. No unique percutaneous treatment has proven effective on both types of cysts. The purpose of this study was to evaluate with volumetric MRI calculations the benefit of percutaneous injection of demineralized bone matrix mixed with autogenous bone marrow on both types of cysts. Twenty-seven cysts; 6 aggressive aneurysmal bone cysts (ABCs) and 21 active simple bone cysts (SBCs) were treated with our percutaneous treatment in this case series. Regular MRIs were performed to calculate their volumetric evolution starting before treatment and with a minimal two-year follow-up. A cyst was considered healed when its final residual volume shrank to less than 50%. To allow statistical comparison between both types of cysts, 13 previously reported ABCs treated with the same protocol in our institution were joined to the 6 present ABCs. Four ABCs healed with a single injection while the 2 others recurred. Five SBCs healed with a single injection, 9 others after a second injection and 2 others after a third injection. Five SBCs were considered non-healed. The present healing rate in 67% of ABCs is consistent with the previous series as there was no significant difference (p=0.37). The better global healing rate for ABC (79%) was not statistically different from the SBC healing rate (76%) (p=0.83). The percutaneous injection of demineralized bone matrix mixed with bone marrow is an effective treatment for both types of cysts.

Results in the surgical treatment of aneurysmal bone cysts - A retrospective data analysis

BACKGROUND

Aneurysmal bone cysts (ABC) are benign tumors mostly occurring in children and young adults. Different open and minimal invasive surgical approaches have been proposed for the treatment of ABCs and yet no consensus is defined to date. The aim of this study was to retrospectively review data of a large single center series of ABCs with patients treated by open curettage with or without filling of the cavity or en-bloc resection. Questions/purposes We asked: (1) What was the local recurrence rate of ABC after surgical treatment at our institution? (2) What were positive or negative predictors for local recurrence? (3) Was there a benefit from adjuvant burring, phenolization or filling, respectively? (4) Where there changes in recurrence free survival in different time periods of primary surgery?

METHODS

By retrospective data analysis of the Vienna Bone and Soft Tissue Tumor Registry, 123 patients surgically treated for primary aneurysmal bone cysts were identified. After exclusion of 33 patients (27%) due to a postoperative follow up below one year, 90 patients who were treated for primary ABCs between 1986 and 2009 were evaluated. These included 50 males and 40 females with a mean age of 16 years (SD 10 years; range: 2 to 51 years). The mean follow-up was 99 months. (SD 72 months, range: 13 to 329 months) RESULTS: Curettage was performed in 84 patients, while 45 patients received adjuvant phenolization. Local recurrence occurred in 28 patients after a mean time of 16 months, with a corresponding local recurrence free survival (RFS) of 83% after one year, 77% after 2 years and 66% after 5 years. ABCs located in hands and feet (p=0.044) showed a superior RFS, while younger patients (p=0.001) displayed an inferior RFS. Regarding adjuvant surgical techniques, mechanical cavity burring (p=0.004) and filling with autologous cancellous bone graft (p=0.024) showed protective effects on RFS. Patients treated between 1986 and 1999 (n=47) had a higher RFS than patients treated between 2000 and 2009 (n=43, p=0.011), as surgeons and surgical indications changed over time.

CONCLUSION

Although curettage, burring, phenolization and reconstruction with bone grafts came with a relatively high risk of local recurrence, open surgery is still justified in aggressively growing ABCs of critical localizations.

LEVEL OF EVIDENCE

IV; therapeutic study.

Aneurysmal bone cyst of the pelvis and sacrum: a single-center study of 17 cases

Background

The aneurysmal bone cyst (ABC) is a benign, but locally aggressive cystic lesion of the bone. It usually occurs in the metaphysis of long bones of adolescents and young adults but can also affect the pelvis.

Methods

This single-center study is a retrospective review of 17 patients with primary ABCs of the pelvis. It examines the importance of polidocanol instillations as minimally invasive treatment option for ABCs of the pelvis compared to intralesional curettage or marginal resection.

Results

Seventeen patients with the diagnosis of a primary ABC of the pelvis were included in the study. Six patients were male (35%) and 11 patients female (65%); the mean age was 18 (9-49) years. The mean follow-up time was 50 months (12-136 months). The most common location of manifestation was the pubis (6; 35%), followed by the ilium (6; 35%), the sacrum (3; 18%) and the ischium (2; 12%). Eight patients were treated by intralesional curettage with the use of adjuvants, one patient by marginal resection, seven by sequential instillation of polidocanol and one patient by simple observation. Five patients received an additional transarterial embolization. After intralesional curettage local recurrence was detected in 4/8 cases (50%). After instillation therapy six patients (86%) had a stable disease without recurrence, only one patient (14%) had a persistent disease with need of additional treatment and was therefore converted to intralesional curettage without local recurrence in the follow-up.

Conclusions

Sequential instillations of polidocanol are a promising, minimally invasive treatment method for ABCs of the pelvis and can be well combined with transarterial embolization.

Aneurysmal bone cyst of the foot: A series of 10 cases

BACKGROUND

Aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor that occurs in childhood and early adulthood. It usually affects the metaphysis of long bones but can also occur in the foot.

METHODS

This single-center study is a retrospective review of ten patients with primary ABCs of the foot which underwent an intralesional curettage or a polidocanol instillation.

RESULTS

After intralesional curettage a local recurrence was observed in 3/5 cases. The instillation of polidocanol showed a significant reduction of the initial cyst volume (p=0.0267). In the instillation subgroup a primary complete healing was achieved in three cases. Due to a persisting disease two cases were converted to intralesional curettage without local recurrence in the follow-up.

CONCLUSIONS

Percutaneous instillation of polidocanol is a minimally invasive treatment option for ABCs of the foot and especially for small bones. Nevertheless, several sequential instillations and a conversion to intralesional curettage can be necessary.

Benign Bone Tumors: An Overview of What We Know Today

Nonmalignant bone tumors represent a wide variety of different entities but maintain many common features. They usually affect young patients, and most can be diagnosed through imaging exams. Often asymptomatic, they can be discovered incidentally. Due to their similarities, these tumors may be challenging to diagnose and differentiate between each other, thus the need for a complete and clear description of their main characteristics. The aim of this review is to give a picture of the benign bone tumors that clinicians can encounter more frequently in their everyday work.

Percutaneous Curettage and Local Autologous Cancellous Bone Graft: A Simple and Efficient Method of Treatment for Benign Bone Cysts

BACKGROUND

Several treatment modalities have been reported to minimize the recurrence after surgical treatment of benign bone cysts. In this study, we evaluated local tumor control, recurrence rate, and bone healing of benign bone cysts after treatment with a simple technique, percutaneous curettage and a local autologous cancellous bone graft.

METHODS

Retrospective analysis of the records of 16 patients diagnosed with benign bone cysts between 2003 and 2010. We documented the demographic data, radiographic signs of healing (progressive decrease in radiolucency, remineralisation, ossification, consolidation of the cyst, and reconstitution of the bone), healing rate, postoperative complications, and recurrence.

RESULTS

Seven of the 16 patients (43.75%) were diagnosed with a simple bone cyst (SBC), while nine (56.25%) had an aneurysmal bone cyst (ABC). On average, radiographic signs of healing were present within 3-6 months, but in two patients these signs presented after 16 months. During the follow-up period, there was no difference in the healing rate between patients with SBC and ABC; no signs of deep or superficial wound infection, no postoperative fracture, and no recurrence in any case over an average of 6.3 years of follow-up.

CONCLUSION

Treatment of benign bone cysts (SBC/ABC) with minimally invasive percutaneous curettage and a local autologous cancellous bone graft is a simple and effective modality with a promising outcome in the local control of recurrence and in enhancing bony consolidation.

Aneurysmal Bone Cyst of the Lateral Malleolus Treated with Intralesional Curettage and Masquelet Technique: A Case Report

An aneurysmal bone cyst is a locally destructive lesion considered to be a pseudotumor arising from the bone. Although this benign-like lesion is generally considered rare, several approaches for treatment have been presented. We report a case involving a 15-year-old female diagnosed with aneurysmal bone cyst of the lateral malleolus. Applying the Masquelet technique enabled the treatment of the lesion without causing instability to the ankle joint and the prevention of recurrence through the application of polymethylmethacrylate. To our knowledge this is the first documented case in our region and possibly in the Philippines.

Current strategies for the treatment of solitary and aneurysmal bone cysts: A review of the literature

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SBCs can mostly be treated conservatively.

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In ABCs a biopsy is compulsory.

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ABCs can be treated by polidocanol instillations adequately.

This review of the literature aims to compare the etiology, the pathogenesis, the clinical diagnostics and the relevant treatment options of two different types of cystic bone lesions: the solitary bone cyst (SBC) and the aneurysmal bone cyst (ABC). Whereas the clinical symptoms and the radiographic appearance can be similar, the diagnostic pathway and the treatment options are clearly different.

The solitary bone cyst (SBC) represents a tumor-like bone lesion, occurring most frequently in the humerus and femur in children and adolescents. Pain caused by intercurrent pathological fractures is often the first symptom, and up to 87% of the cysts are associated with pathological fractures. In the majority of cases SBCs can be treated conservatively, especially in the upper extremity. However, if a fracture is completely dislocated, joint affecting, unstable or open, surgical treatment is necessary. Pain under weight bearing or regaining the ability to mobilize after fracture timely can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution can be seen in rare cases.

The aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor that occurs in childhood and early adulthood. It usually affects the metaphysis of long bones but can also occur in the spine or the pelvis. ABC can be primary but also secondary to other bone pathologies. The diagnosis has to be confirmed by biopsy and histopathological examinations. With cytogenetic studies and the detection of specific translocations of the ubiquitin-specific protease (USP) 6 gene primary ABCs can be differentiated from secondary ABCs and other bone lesions. Among various modalities of treatment i.e. en bloc resection, intralesional curettage with adjuvants, embolization or the systemic application of denosumab, intralesional sclerotherapy using polidocanol is an effective and minimally invasive treatment of primary ABCs.

Primary Aneurysmal Bone Cyst and Its Recent Treatment Options: A Comparative Review of 74 Cases

(1) Background: An aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor. Different treatment modalities are described in the literature i.e., en bloc resection, intralesional curettage and percutaneous sclerotherapy. (2) Methods: This single-center study is a review of 74 patients with primary ABCs who underwent a surgical treatment or polidocanol instillation. Cyst volume measurements using MRI and conventional radiographs are compared. (3) Results: The mean pre-interventional MRI-based cyst volume was 44.07 cm³ and the mean radiographic volume was 27.27 cm³. The recurrence rate after intralesional curettage with the need for further treatment was 38.2% (13/34). The instillation of polidocanol showed a significant reduction of the initial cyst volume (p < 0.001) but a persistent disease occurred in 29/32 cases (90.6%). In 10 of these 29 cases (34.5%) further treatment was necessary. After en bloc resection (eight cases) a local recurrence occurred in two cases (25%), in one case with the need for further treatment. (4) Conclusions: MRI scans are superior to biplanar radiographs in the examination of ABCs. Sequential percutaneous instillations of polidocanol are equally effective in the therapy of primary ABCs compared to intralesional curettage. However, several instillations have to be expected. In a considerable number of cases, a conversion to intralesional curettage or en bloc resection may be necessary.

Is sclerotherapy with polidocanol a better treatment option for aneurysmal bone cyst compared to conventional curettage and bone grafting?

BACKGROUND

The standard treatment of Aneurysmal bone cyst is curettage and grafting and is associated with high morbidity. Hence minimal invasive alternative treatment methods such as sclerotherapy are gaining much popularity. Though sclerotherapy has been attributed to reasonable cure rates, undetermined tissue diagnosis often impedes with initiation of treatment. This study examines if sclerotherapy with polidocanol based on clinic-radiological picture is comparable with the standard intralesional curettage and bone grafting. Attempting biopsy and treatment simultaneously based on the clinico-radiological presentation makes this study unique.

METHODS

We divided 48 patients into two treatment groups. Group 1 treated with percutaneous sclerotherapy using polidocanol and group 2 those treated with extended curettage and bone grafting. We assessed time to healing and recurrence, pain relief, and radiological outcome using modified Neer's criteria for the radiological healing of the bone cysts. 31 patients from Group 1 and 17 from Group 2 were available for study. The minimum follow-up was 2 years.

RESULTS

At last follow-up, 100% in Group 1 and 82% in Group 2 had achieved complete healing and there was no statistical difference in outcome at 24 months (p = 0.255). Complications in Group 1 were injection site necrosis, pain and hypopigmentation, all of which resolved spontaneously. In Group 2, three patients had recurrence. Despite similar healing rates, we found higher incidence of clinically pertinent complications, poor functional outcomes and increased cost of treatment associated with intralesional excision.Three cases were excluded from sclerotherapy group as the final diagnosis turned up to be secondary ABC.

CONCLUSIONS

Percutaneous sclerotherapy using polidocanol is a highly effective, cost efficient and safe treatment option with good cosmesis and reduced morbidity. In this study, we found comparable outcomes for both treatment methods however this will require confirmation in larger studies.

Limb Length Discrepancy and Angular Deformity due to Benign Bone Tumors and Tumor-like Lesions

Benign bone tumors and tumor-like lesions are frequently diagnosed in children and adolescents. The immature skeleton is at risk for growth disturbances and deformity because of the effects of the lesions on normal bone architecture and the physis. The development, manifestation, and severity of the limb length inequality and deformity differs between the various bone pathologies. Distraction osteogenesis, osteotomy, and guided growth are key tools in the treatment of limb inequality and deformity using a combination of external and internal fixation devices.

An Extraosseous Aneurysmal Bone Cyst in a 59-Year-Old Man: A Case Report

CASE

A 59-year-old man presented with a history of a painful, rapidly growing mass on the anteromedial aspect of his thigh. On examination, he had a mobile, hard, and nontender mass. Magnetic resonance imaging revealed a well-encapsulated, heterogeneous mass with high-intensity internal septations. Blood-filled spaces were observed within the mass with no involvement of the underlying normal bony structures. The mass was excised, and the diagnosis of an extraosseous aneurysmal bone cyst was confirmed histologically.

CONCLUSIONS

Extraosseous aneurysmal bone cysts are rare benign lesions that can mimic malignant tumors. Careful clinical and pathological assessment should be performed in such cases.

Is percutaneous injection of bone marrow concentrate, demineralized bone matrix and PRF an alternative to curettage and bone grafting for treating aneurysmal bone cyst?

To determine the efficacy and safety of a single injection with autologous bone marrow concentrate (BMC) combined with demineralized bone matrix (DBM) and platelet-rich fibrin (PRF) compared to curettage and bone grafting for treating aneurysmal bone cysts (ABC). Two hundred thirty-nine patients were treated with curettage and bone grafting (Curettage Group), and 21 with percutaneous injection of DBM associated with autologous BMC and PRF (DBM + BMC + PRF Group). All patients attended the outpatient clinic to assess ABC healing and clinical results at the first 3, 6, 9 and 18 months after surgery and then annually in the absence of symptoms. The mean follow-up was 42 months for the Curettage Group (range 6-180 months) and 28 months for the DBM + BMC + PRF Group (range, 6-85 months). Out of the 21 patients who had injection with BMC, DBM, and PRF, 17 (80%) require no additional treatment and they were considered healed. Of the 239 patients treated with curettage and bone grafting after core needle or open biopsy, 177 (74%) were considered healed after the first treatment. Injection in comparison with curettage presented the same risk for local recurrence. The overall rate of local recurrence for all patients was 25%. Univariate and multivariate analyses showed a significant difference in local recurrence rates in patients younger than 15 years, and for the cyst located in the long bones of the lower limbs than the cyst located in the long bones of the upper limbs.

Efficacy of treatment interventions for primary aneurysmal bone cysts: a systematic review

AIMS

Aneurysmal bone cysts (ABCs) are locally aggressive lesions typically found in the long bones of children and adolescents. A variety of management strategies have been reported to be effective in the treatment of these lesions. The purpose of this review was to assess the effectiveness of current strategies for the management of primary ABCs of the long bones.

METHODS

A systematic review of the published literature was performed to identify all articles relating to the management of primary ABCs. Studies required a minimum 12-month follow-up and case series reporting on under ten participants were not included.

RESULTS

A total of 28 articles meeting the eligibility criteria were included in this review, and all but one were retrospective in design. Due to heterogeneity in study design, treatment, and outcome reporting, data synthesis and group comparison was not possible. The most common treatment option reported on was surgical curettage with or without a form of adjuvant therapy, followed by injection-based therapies. Of the 594 patients treated with curettage across 17 studies, 86 (14.4%) failed to heal or experienced a recurrence. Similar outcomes were reported for 57 (14.70%) of the 387 patients treated with injection therapy across 12 studies. Only one study directly compared curettage with injection therapy (polidocanol), randomizing 94 patients into both treatment groups. This study was at risk of bias and provided low-quality evidence of a lack of difference between the two interventions, reporting success rates of 93.3% and 84.8% for injection and surgical treatment groups, respectively.

CONCLUSION

While both surgery and sclerotherapy are widely implemented for treatment of ABCs, there is currently no good quality evidence to support the use of one option over the other. There is a need for prospective multicentre randomized controlled trials (RCTs) on interventions for the treatment of ABCs. Cite this article: Bone Jt Open 2021;2(2):125-133.

Mineral and Bone Consequences of High Dose Denosumab Therapy to Treat an Aneurysmal Bone Cyst, a Child Case Report

Aneurysmal bone cysts (ABCs) are rare benign pseudotumoral bone lesions with potential aggressive behavior due to the extensive destruction of surrounding bone. Traditionally, these tumors were treated with open surgery, but there is more and more a shift to less invasive procedures. In particular, treatment for spinal ABCs is generally unsatisfactory due to the risk of morbidity, neurological impairment and recurrence, and there is a need for innovative therapies. Denosumab has been reported as a useful treatment in giant cell tumors of bone (GCTB), so its efficacy has been tested also in other fibro-osseus lesions affecting children and adolescents, such as spinal aneurysmal bone cysts. The pediatric literature is limited to case reports and small series, all of which highlight the efficacy of this treatment on lesions growth and associated bone pain. Some of these reports have already reported well known side effects associated with denosumab, such as hypocalcemia at the beginning of the treatment, and rebound hypercalcemia at the discontinuation. The latter seems to be more frequent in children and adolescents than in adults, probably due to the higher baseline bone turnover in children. In addition, the use of denosumab in young patients could affect both bone modeling and remodeling, even if the consequences on the growing skeleton have not been reported in detail. Here we describe the case of a spinal ABC diagnosed in an 8-year old young boy which was not accessible to surgery but responded favorably to denosumab. Our aim is to describe the rapid changes in mineral and bone homeostasis in this patient, that required advice from the experts of the European Reference Network (ERN) for rare bone and endocrine diseases.

Aneurysmal bone cyst in the pelvis of a cat: successful outcome of partial iliectomy with limb preservation

Case summary

A 3-year-old spayed female domestic shorthair indoor cat presented with a 3-week history of pain from the pelvic region. Physical examination revealed pain elicited on palpating the pelvic area and right hip. Radiographs and CT showed an expansile, osteolytic process with intact cortex in the right wing of the ilium. CT revealed a monostotic and soft tissue-attenuating process with clear margins. Preoperative histopathological diagnosis of aneurysmal bone cyst was made from incisional biopsies. The cyst was removed en bloc with limb-sparing partial iliectomy. Histopathology confirmed the diagnosis of aneurysmal bone cyst. Recovery from surgery was uneventful. At re-examination 8 weeks and 8 months postoperatively, the cat was pain free and physical examinations were within normal limits.

Relevance and novel information

Feline aneurysmal bone cysts are rare and reported cases are few. To our knowledge, this is the first report describing the CT appearance of a pelvic aneurysmal bone cyst and partial iliectomy with limb preservation in a cat with successful short-term outcome.

Aneurysmal bone cyst inadvertently treated with chemotherapy-A series of three cases

Aneurysmal bone cyst (ABC) is a benign locally aggressive tumor that occurs in childhood and early adulthood. Most relevant differential diagnoses are the telangiectatic osteosarcoma and the giant cell tumor. In the present case series chemotherapy following the EURAMOS or the Euro-Ewing 99 protocol was externally applied in three patients with the misdiagnosis of ABC as malignant bone tumor. In all three cases, a significant reduction of the volume of the ABC was achieved. This is the first report about the use of neoadjuvant chemotherapy in ABC. Chemotherapy reduces the size of an ABC and leads to progressive sclerosis.

Do Bisphosphonates Alleviate Pain in Children? A Systematic Review

PURPOSE OF REVIEW

The goal of this systematic review is to analyze the effectiveness of bisphosphonates (BPs) to treat bone pain in children and adolescents who have diseases with skeletal involvement.

RECENT FINDINGS

We included 24 studies (2 randomized controlled trials, 3 non-randomized controlled trials, 10 non-randomized open-label uncontrolled studies, 8 retrospective studies, and 1 study with design not specified). The majority of included studies assessed pain from a unidimensional approach, with pain intensity the most frequently evaluated dimension. Only 38% of studies used validated tools; visual analogue scale was the most frequently employed. BPs were used to alleviate bone pain in a wide variety of pediatrics conditions such as osteogenesis imperfecta, secondary osteoporosis, osteonecrosis related to chemotherapy, chronic non-bacterial osteitis, idiopathic juvenile osteoporosis, unresectable benign bone tumor, and cancer-related pain. Twenty of the 24 studies reported a positive effect of BPs for alleviating pain in different pathologies, but 58% of the studies were categorized as having high risk of bias. Intravenous BPs are helpful in alleviating bone pain in children and adolescents. It is advised that our results be interpreted with caution due to the heterogeneity of the doses used, duration of treatments, and types of pathologies included. In addition, this review shows the paucity of high-quality evidence in the available literature and further research is needed.

TRIAL REGISTRATION

Before the completion of this review, the protocol was registered to PROSPERO (International prospective register of systematic reviews), PROSPERO 2020 ID # CRD42020158316. Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020158316.

Tailored treatment of aneurysmal bone cyst of the scapula: en bloc resection for the body and extended curettage for the neck and acromion

BACKGROUND

The acromion and neck of the scapula are essential components of shoulder function, but the body section is less critical. We treated aneurysmal bone cysts (ABCs) of the neck and ‏acromion with extended curettage and ABCs of the body with en bloc resection.‏ This article reports on local recurrence and the functional outcomes of this approach.

MATERIALS AND METHODS

Seventeen patients with primary ABCs of the scapula were included in this retrospective study. We treated 10 patients with extended curettage and bone grafting and 5 patients with en bloc resection. In 2 cases, both the body and neck were involved. We treated these patients with a combination of curettage and resection. We used the Musculoskeletal Tumor Society score for functional assessment of outcomes.

RESULTS

The mean age of the patients was 20.5 ± 7.4 years. One local recurrence occurred in patients who underwent extended curettage and bone grafting (1 of 12 cases, 8.3%). No recurrence was observed in patients who underwent en bloc resection alone. The mean Musculoskeletal Tumor Society score was 27.9 ± 1 in patients who underwent curettage alone and 24.86 ± 0.7 in patients who underwent en bloc resection alone or in combination with curettage (P < .001).

CONCLUSION

Despite the higher risk of local recurrence after curettage, this method can be selected for the treatment of ABCs of the acromion and neck of the scapula to minimize shoulder disability. For the body of the scapula, en bloc resection is a more reasonable treatment, despite a higher rate of functional impairment.

Challenges in the Diagnosis and Treatment of Aneurysmal Bone Cyst in Patients with Unusual Features

Objectives

Aneurysmal bone cyst (ABC) is a benign but locally aggressive tumor. It has several challenging features. The aim of this study is to identify challenges in the diagnosis and treatment of ABC especially in patients with unusual features.

Methods

This retrospective study involved medical record review of primary ABC patients with one or more of the following features: unusual clinical presentation with a mass or a pathological fracture especially at an unusual age, rare locations, radiological findings suggesting other diagnoses especially sarcoma, and a nondiagnostic histopathology of biopsy samples.

Results

25 patients (17 males and 8 females) were included. Most patients were either younger than 10 or older than 20 years. 10 patients presented with a mass or a pathological fracture. Unusual locations include the scapula, the olecranon, the hamate, the calcaneus, and the first metatarsal bone. Extension into the epiphysis occurred in 2 patients with proximal fibula and olecranon ABCs. Two separate synchronous cysts existed in the proximal epiphysis and middiaphysis of one humerus. Radiological imaging suggested other primary diagnoses in 8 patients. Core needle biopsy was diagnostic in only 2 of 7 patients. The main treatment was intralesional resection/curettage with bone grafting. Wide resection was performed in 4 patients. Recurrence rate was 28%. Recurrence risk factors included the following: age less than 10 years, male gender, and proximal femur location. Late recurrence occurred in 3/7 patients. One patient with asymptomatic radiological recurrence showed subsequent spontaneous resolution one year later.

Conclusions

This study presented multiple unusual features of ABC including: unusual age, rare locations, and nondiagnostic radiological and histopathological findings. These features can complicate the diagnosis and management. Given these features, especially with pathological fractures, a well-planned incision, the use of frozen section examination, and the application of either external fixation or plate osteosynthesis for fracture fixation can be recommended.

Aneurysmal bone cyst treated with percutaneous doxycycline: is a single treatment sufficient?

OBJECTIVE

The purpose of this case series is to report on the effectiveness of a single percutaneous injection of doxycycline as a primary treatment for aneurysmal bone cyst (ABC).

MATERIALS AND METHODS

A retrospective cohort study was conducted on seven patients diagnosed with ABC at various anatomical sites, with the intention to treat by a single percutaneous injection of doxycycline. Mean patient age was 14 years.

RESULTS

Signs of treatment response were seen in six of seven patients after one injection. Three of the seven received a second treatment, despite signs of response. Another had expansion of the lesion after treatment, requiring excision. In total, three patients had a single injection of doxycycline as their sole treatment and another three showed signs of response after a single injection.

CONCLUSIONS

A single percutaneous injection of doxycycline should be considered a viable primary treatment option for ABC.

Examination and Management of a 4-Year-Old Following a Femoral Aneurysmal Bone Cyst: A Case Report

PURPOSE

The literature lacks recommendations for postoperative rehabilitation following removal of aneurysmal bone cysts (ABCs). This case report describes the rehabilitation with return to age-appropriate functional activities for a 4-year-old following surgical fixation of a femoral ABC, with emphasis on clinical decision-making in the absence of definitive treatment algorithms.

SUMMARY OF KEY POINTS

The child improved in range of motion, strength, balance, transfers, gait, stair negotiation, and percentile rank on the Test of Gross Motor Development 2.

CONCLUSION

This case is successful outcomes of a 4-year-old girl (GP) following surgical fixation for an ABC.

RECOMMENDATIONS FOR CLINICAL PRACTICE

This case fills a current void in the literature emphasizing clinical decision-making and attainment of GP-specific functional goals. A goal-driven approach incorporating key elements of the International Classification of Function model resulted in successful return to age-appropriate activity following surgical fixation of a femoral fracture due to an ABC.

Denosumab Therapy in the Management of Aneurysmal Bone Cysts: A Comprehensive Literature Review

Aneurysmal bone cysts (ABCs) are uncommon lesions that involve the axial and appendicular bones. Although biologically benign, ABCs have the tendency to assume an aggressive behavior causing local destruction of the underlying bone and neighboring soft tissues. Morphologically, ABCs are composed of cyst-like cavities filled with blood and bounded by an array of diverse cells including fibroblasts, inflammatory infiltrates and osteoclast-like multinucleated giant cells. From a molecular perspective, the osteoclast-like multinucleated giant cells harbor high expression of receptor activator of nuclear factor kappa B (RANK) receptors, whereas the neoplastic stromal cells harbor high expression of RANK ligand (RANKL). The RANK-RANKL interaction has been implicated in the carcinogenesis of ABCs and giant cell tumor of bones (GCTBs). Currently, the optimal management of ABCs remains a hotly debated topic. There are a multitude of treatment modalities (that is, surgery, sclerotherapy, radiotherapy and selective arterial embolization), and each modality has its own benefits, morbidity and risk of complications. The local aggressiveness of ABC and its high rates of relapse following treatment has demanded the march towards discovering more innovative therapies. One of such therapies is denosumab, a monoclonal antibody targeted against the RANKL. Denosumab is already approved by the United States Food and Drug Administration (FDA) for the treatment of adults and skeletally mature adolescents with GCTB that is unamenable to surgery, or initial surgery is anticipated to result in significant morbidity. However, denosumab is not approved by the FDA for the management of ABCs. However, taking into consideration the morphological similarity between GCTBs and ABCs, some treating physicians have logically opted to use denosumab in an off-label manner to treat select ABCs. To the best of knowledge, no study has attempted to summarize the related literature on the use of denosumab in ABCs. Therefore, the primary aim of this study is to narratively review all the available literature about the efficacy and safety of the use of off-label denosumab in the management of patients with ABCs.

Complete resolution of a cervical spine aneurysmal bone cyst after single session of endovascular embolization: Case report

Treatment options for aneurysmal bone cysts include intralesional curettage, segmental excision, en bloc resection and endovascular embolization. The most commonly used treatment is intralesional curettage and selective arterial embolization is normally an adjunctive therapy, not a definitive treatment. We report a case of a C1 lateral mass aneurysmal bone cyst treated with a single session of endovascular embolization. Long-term follow up demonstrated complete resolution of the cyst. A study of aneurysmal bone cyst embolization was conducted and the key points for obtaining maximal devascularization of the cyst along with embolic material and technique are discussed.

Denosumab in patients with aneurysmal bone cysts: A case series with preliminary results

Purpose:

Aneurysmal bone cyst (ABC) is a rare skeletal tumor usually treated with surgery/embolization. We hypothesized that owing to similarities with giant cell tumor of bone (GCTB), denosumab was active also in ABC.

Methods:

In this observational study, a retrospective analysis of ABC patients treated with denosumab was performed. Patients underwent radiologic disease assessment every 3 months. Symptoms and adverse events were noted.

Results:

Nine patients were identified (6 male, 3 female), with a median age of 17 years (range 14–42 years). Primary sites were 6 spine–pelvis, 1 ulna, 1 tibia, and 1 humerus. Patients were followed for a median time of 23 months (range 3–55 months). Patients received a median of 8 denosumab administrations (range 3–61). All symptomatic patients had pain relief and 1 had paresthesia improvement. Signs of denosumab activity were observed after 3 to 6 months of administration: bone formation by computed tomography scan was demonstrated in all patients and magnetic resonance imaging gadolinium contrast media decrease was observed in 7/9 patients. Adverse events were negligible. At last follow-up, all patients were progression-free: 5 still on denosumab treatment, 2 off denosumab were disease-free 11 and 17 months after surgery, and the last 2 patients reported no progression 12 and 24 months after denosumab interruption and no surgery.

Conclusions:

Denosumab has substantial activity in ABCs, with favorable toxicity profile. We strongly support the use of surgery and/or embolization for the treatment of ABC, but denosumab could have a role as a therapeutic option in patients with uncontrollable, locally destructive, or recurrent disease.

Treatment of aneurysmal bone cysts using endoscopic curettage

Background

Although aneurysmal bone cysts (ABCs) are benign tumours, they have the potential to be locally aggressive. Various treatment approaches, such as en bloc resection, open curettage, radiotherapy, sclerotherapy, and embolization have been proposed, but the most appropriate treatment should be selected after considering the risk of tumour recurrence and treatment complications. Endoscopic curettage (ESC) may be a less invasive alternative to open curettage for ABC treatment. We aimed to describe the use of ESC for the treatment of ABCs and to report our clinical outcomes, including the incidence rate of recurrence, radiological appearance at final follow-up, time to solid union, complications, and postoperative function.

Methods

Between 1998 and 2015, 30 patients (18 men and 12 women; mean age, 17.4 years) underwent ESC for the treatment of primary ABCs at our hospital (mean postoperative follow-up, 55 months). ESC was performed under arthroscopic guidance for direct visualization, and curettage extended until normal bone was observed in the medullary cavity. To investigate bone healing after ESC, we evaluated the consolidation of cysts at the final evaluation (based on the modified Neer classification) and time to solid union after surgery, which was defined as sufficient cortical bone thickness to prevent fracture and allow physical activities.

Results

Recurrence was identified in 3 cases (10%). Curative outcomes were obtained after repeated ESC or open curettage. A log-rank analysis indicated that age < 10 years (p = 0.004) and contact of the tumour with the physis (p = 0.01) increased the risk of tumour recurrence. Residual tumours were identified in 9 cases (30%); these lesions remained inactive over the extended follow-up period. The average time to solid union after endoscopic curettage was 3.2 months. Transient radial nerve palsy was identified in 1 case. Good postoperative functional recovery occurred in all cases.

Conclusions

ESC is a minimally invasive technique for the treatment of ABCs, and the tumour recurrence rate is comparable to that of other standard procedures. However, the application of this method should be carefully considered, especially for patients < 10 years and when the tumour comes in contact with the physis.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2176-6) contains supplementary material, which is available to authorized users.

Sclerotherapy using Surgiflo and alcohol: a new alternative for the treatment of aneurysmal bone cysts

PURPOSE

This study aims to review the results of sclerotherapy using Surgiflo in addition to alcohol in primary aneurysmal bone cysts (ABC).

METHODS

A total of 16 consecutive patients with histologically confirmed diagnosis of primary ABC were treated by percutaneous Surgiflo and alcohol injection at our institution. Clinical follow-up included the assessment of pain, swelling, limping and functional impairment. Radiological parameters included tumour volume, physis-cyst distance, thickness of cyst cortex, and presence of intracystic septations. Mean follow-up was 35,6 months (24-71 months). Treatment was considered successful when the cyst volume decreased by a minimum of 10%, the bone cortex became thicker, and the distance to physis increased.

RESULTS

Mean age at presentation was 9.5 years (5.16-13.84 years). All ABC's were primary and all patients underwent a single Surgiflo and alcohol session except for two (12.5%) who required a second session. All patients had a good clinical result at final follow-up. Satisfactory cyst healing was achieved in 11 cases according to radiological parameters. Tumour volume decreased from a mean of 122 cm³ (111 to 133) before injection to 86 cm³ (76 to 96) at last follow-up (p < 0.01). Physis-cyst distance increased from a mean of 1 cm (0.1 to 2) to 2.1 cm (0.5 to 4) at last follow-up (p < 0.01). Cortical thickness improved from 1 mm (0.5 to 1.5) to 2 mm (1 to 3.5) at last follow-up (p < 0.01).There were no treatment related complications. Surgery was performed in one patient having a C3 vertebra ABC after developing quadriparesis due to tumour progression.

CONCLUSION

Sclerotherapy using Surgiflo and alcohol may be used as an efficient, safe and minimally invasive alternative for the treatment of primary ABCs.

Radiotherapy for aneurysmal bone cysts : A rare indication

BACKGROUND

Aneurysmal bone cysts (ABC) are rapidly growing benign osseous lesions composed of blood-filled channels separated by fibrous septa. Since the value of external beam radiotherapy (EBRT) for ABC has not been well defined, the German Cooperative Group on Radiotherapy for Benign Diseases performed the national register study described herein.

PATIENTS AND METHODS

Five German institutions collected data regarding clinical features, treatment concepts, and outcome for patients with ABC who had been referred for local EBRT over the past 30 years.

RESULTS

Between 1990 and 2015, 10 patients with ABC were irradiated (5 female/5 male). Median age was 23 years (range 14-40 years). Involved sites were: spine (n = 3), sacrum/pelvis (n = 2), shoulder/scapula (n = 2), humerus (n = 1), femur (n = 1), and radius (n = 1). The median EBRT total and fractional doses were 28 Gy (range 5-40 Gy) and 2 Gy (range 1-2 Gy), respectively. Median follow-up was 65 months (range 12-358 months). Persistent pain relief was achieved for all patients. However, long-term follow-up response data were only available for 7/10 patients. All 7 patients exhibited a radiological response and experienced no recurrent disease activity or pain during follow-up. Acute and late radiogenic toxicities ≥ grade 3 and secondary malignancies were also not observed.

CONCLUSION

Primary or adjuvant EBRT seems to be an effective and safe treatment option for persistent or recurrent ABC. Fractionated doses below 30 Gy may be recommended.