[Aneurysmal Bone Cyst of the Rib:Report of a Case].

We report a case of an aneurysmal bone cyst (ABC) originating in a rib. A 34-year-old woman was admitted to our medical department for evaluation of left rib pain and an abnormal shadow in the left 7th rib observed on chest radiography. Computed tomography (CT) revealed an osteolytic lesion involving the left 7th rib. Positron emission tomography/CT showed slight fluorodeoxyglucose uptake in the lesion. We performed 7th rib resection with a 4 cm margin from the tumor, including the intercostal muscles in the 6th and 7th interspaces. Histopathological examination of the resected specimen showed multiple blood-filled spaces and fibrous trabeculae, which confirmed the diagnosis of an ABC. The patient's postoperative course was uneventful. Although rare, clinicians should consider ABCs in the differential diagnosis of rib tumors.

Hexapod Frame Correction of Proximal Tibial Recurvatum Caused Indirectly by a Femoral Aneurysmal Bone Cyst in an Adolescent: A Case Report and Systematic Review.

CASE: A 16-year-old boy presented with a recurrent distal femur aneurysmal bone cyst accompanied by a combined sagittal knee deformity (20° of femoral antecurvatum and 26.8° of tibial recurvatum) and limb shortening. After preoperative planning, the treatment involved new intralesional curettage, phenolization, and bone allograft filling. Additional procedures included distal extension femoral osteotomy with plate fixation, and proximal tibial osteotomy with, gradually corrected through a hexapod frame. At 2-year follow-up, lower limbs exhibited normoalignment and equal length. CONCLUSION: Complex knee deformities may occur with tumoral lesions around the knee but can be effectively addressed through double osteotomy and application of a hexapod frame.

[Clinical, imaging and pathological and molecular characteristics of simple bone cyst].

Objective: To investigate the radiologic, pathologic, and molecular features of simple bone cysts (SBC), and their differential diagnoses. Methods: Fourteen cases of SBC were collected at the Department of Pathology, the First Affiliated Hospital of Nanjing Medical University from 2017 to 2022, and fluorescence in situ hybridization (FISH) was performed for retrospective analysis. Results: There were 14 patients, including 7 females and 7 males, with age range of 7 to 45 (median 29) years. The most common complaint was pain, including 4 cases with pathological fracture and 5 with history of previous trauma. The tumor size ranged from 3.4 to 13.5 (median 5.6) cm. The lesion involved the femur (n=4), humerus (n=5) and iliac bone (n=5). Radiologic diagnoses included SBC, aneurysmal bone cyst, and giant cell tumor of the bone or its combination with aneurysmal bone cyst-like region and fibrous dysplasia. Histologically, the cyst walls of the lesions were composed of fibrous tissue, fibrin-like collagen deposits, bone-like matrix and occasional woven bone. The lesional cells were spindled to ovoid, with scattered osteoclast-like giant cells, foamy histiocytes, hemosiderin deposits and cholesterol clefts. In 6 cases there were nodular fasciitis-like areas. Immunohistochemically, the spindled to ovoid cells were positive for SMA, EMA and SATB2 in varying degrees. FISH detection was performed in all 14 cases and EWSR1/FUS rearrangement were found in 9 cases. One case of FUS::NFATC2 fusion was detected by next-generation sequencing. Nine cases of SBC with the rearrangement were more cellular, and there were more mitotic figures in the recurrent FUS::NFATC2 fusion tumor. Clinical follow-up was obtained in all 14 cases with the time ranging from 5 to 105 (mean 46) months. Amongst them, the tumor with FUS::NFATC2 rearrangement had local recurrence twice after the first local excision, but had no more recurrence or metastasis 34 months after the subsequent segmental resection. The other 13 cases had no recurrence. Conclusions: EWSR1 or FUS rearrangement is most commonly identified in SBC, suggesting that SBC might be a neoplastic disease. In cases where the radiologic appearance and histomorphology are difficult to differentiate from aneurysmal bone cyst, FISH detection can aid in the definitive diagnosis.

[Pediatric neurosurgical treatment of aneurysmal bone cyst at the level of thoracic spine]. / Aneurysmás csontcysta gyermek-idegsebészeti megoldása a háti gerinc magasságában.

Aneurysmal bone cysts are benign but locally aggressive bone tumours, most often affecting children and young adults. In this case report, we present the clinical  picture of a 15-year-old boy with progressive, chronic back pain. An MRI of thoracic spine  confirmed a T2 cystic spinal tumour. After considering potential options surgical removal was our choice and gross total removal was achieved with T1-3 short-segment fixation. Aneurysmal bone cysts are often rapidly expanding lesions with vascular  transformation. In order to avoid irreversible damage, in addition to early diagnosis, it is necessary to carefully consider the therapeutic options, perform surgical removal and stabilization as necessary. In case of the presented patient, extensive surgical removal and short-segmentation were performed. At 18 months of follow-up, he had no complaints and was asymptomatic. Follow-up imaging studies showed no residual or recurrent tumour to date.

Intraosseous hemangioma with aneurysmal bone cyst-like changes of the hyoid bone: Case report and literature review.

RATIONALE: Intraosseous hemangioma is a rare benign vascular tumor of the bone that can affect any body part; however, the most common site is the vertebra, followed by calvarial bones. PATIENT CONCERNS: We present a case of intraosseous hemangioma in a 23-year-old male who presented a feeling of fullness in the throat for 3 months. The hyoid bone level had a hard mass of about 5 cm. Fine needle aspiration showed 5 mL dark bloody aspirates. Magnetic resonance image showed a 5.3 cm mixed signal intensity lesion in the hyoid body. DIAGNOSIS: Histopathologic examination showed intraosseous hemangioma with aneurysmal bone cyst (ABC)-like changes in the hyoid bone. INTERVENTIONS: The mass was completely removed without significant problems. OUTCOMES: Complete mass excision and symptomatic improvements were achieved, and no subsequent relapses were observed. LESSONS: The authors experienced a case of intraosseous hemangioma with ABC-like changes. There has been no case report of intraosseous hemangioma in the hyoid bone. This case showed a spectral pattern of the ABC-like changes developing from the underlying bone tumor as a secondary change. ABC-like changes in bone tumors can mislead the diagnosis. Careful examination of the tumor is essential for the correct diagnosis of ABC or ABC-like changes.

Autogenous fibula head transplantation for aneurysmal bone cyst of distal radius: A case report followed up for 7 years.

RATIONALE: Aneurysmal bone cyst (ABC) is a rare primary or secondary tumor that usually occurs in young women aged between 10 and 20 years, mostly in the long tubular bone and spine. However, there are no definite standards for its clinical treatment. To our knowledge, this is the first report of a young female patient with distal radius ABC who was successfully treated with tumor resection and autogenous fibular head transplantation. PATIENT CONCERNS: A 28-year-old married Chinese young woman presented to our hospital with swelling and pain in her right wrist for 2 years and aggravation of wrist movement restriction for 1 week. DIAGNOSES: Pathological biopsy confirmed ABC. INTERVENTIONS: We performed a pathological examination of the tumor on the right wrist and preliminarily confirmed the diagnosis of ABC. The right wrist joint was reconstructed by total surgical resection of the ABC tumor in the right wrist joint and autogenous fibular head transplantation. OUTCOMES: During follow-up within 7 years, good right wrist function was confirmed. The tumor did not recur, the swelling of the right wrist disappeared, the joint pain and limitation of movement significantly improved, and the function of the right wrist was not impaired in daily activities. Radiography showed that the fracture had healed. LESSONS: Our results suggest that autofibular head transplantation is an effective treatment for reconstruction of wrist function in adult patients with ABC of the distal radius.

Aneurysmal bone cysts: A UK wide tumor center experience.

BACKGROUND AND OBJECTIVES: This multicenter retrospective series of consecutive extra-spinal aneurysmal bone cysts aims to identify risk factors for treatment failure. METHODS: Aneurysmal bone cysts treated within seven collaborating centers with over 12-months follow-up were eligible for inclusion. Survival analyses were performed to identify variables associated with recurrence using log-rank tests and Cox proportional hazard regression. RESULTS: One hundred and fifteen (M:F 60:55) patients were included. Median age at presentation was 13 years and median follow-up was 27 months. Seventy-five patients underwent surgical curettage and 27% of these required further intervention for recurrence. Of the 30 patients who underwent biopsy with limited percutaneous curettage as initial procedure, 47% required no further treatment. Patients under 13 years (log-rank p = 0.006, HR 2.3, p = 0.011) and those treated who had limited curettage (log-rank p = 0.001, HR 2.7, p = 0.002) had a higher risk of recurrence/persistence. CONCLUSIONS: There is a high risk of recurrence following surgical treatment for aneurysmal bone cysts and this risk is higher in young patients. However, the cyst heals in a substantial number of patients who have a limited curettage at the time of biopsy.

Unusual presentation of aneurysmal bone cyst (ABC) in children: pediatric intracranial osteosarcoma with secondary ABC.

A 13-year-old female patient presented with painless vision loss and proptosis for 18 months. Imaging findings were highly suggestive of a supraorbital aneurysmal bone cyst (ABC) for which she underwent complete surgical excision. Postoperatively, she developed left hemiparesis. Computed tomography angiography (CTA) revealed right complete internal carotid arterial (ICA) thrombosis. This was managed conservatively, and she improved in hemiparesis over the next 3 weeks. Histopathology report revealed osteosarcoma with secondary ABC, for which she was referred for radiotherapy. At 1.5 months follow-up, the patient's left lower limb power improved to 4 + /5. She was walking without support, and her left upper limb power was 4/5.

Adjunct role of liquid absolute alcohol intralesional sclerotherapy during the surgical management of spinal primary aneurysmal bone cyst in a child: a technical case report.

BACKGROUND: Aneurysmal bone cyst is composed of variable -sized cystic blood-filled spaces separated by connective tissue septae. First-line surgical resection of spinal aneurysmal bone cyst in a child with limited total blood volume can lead to massive intraoperative bleeding, thus limiting extent of resection. Our Centre's has good experience of using absolute alcohol as an effective immediate devascularizing agent during vertebral hemangioma surgery in children. MATERIAL AND METHODS: We report the first case of pediatric lumbar primary aneurysmal bone cyst in which completely blood-less piecemeal total resection of the lesion was performed after intraoperative absolute alcohol intralesional sclerotherapy. RESULTS: Completely blood-less piecemeal total resection of the lumbar aneurysmal bone cyst was performed after intraoperative absolute alcohol intralesional sclerotherapy. CONCLUSION: Intraoperative absolute alcohol intralesional sclerotherapy is a very effective devascularizing adjunct for complete piecemeal resection of spinal aneurysmal bone cyst in children with limited blood volume.

Use of Surgical Adjuvants Does Not Decrease Recurrence of Aneurysmal Bone Cysts in Surgical Intervention With Pediatric Patients.

BACKGROUND: Aneurysmal bone cysts (ABCs) are benign active tumors often requiring intralesional curettage with or without adjuvants. The primary aim of this study was to analyze whether recurrence is influenced by the use of surgical adjuvants in pediatric patients with ABCs. Secondary aims examined recurrence rates based on age, sex, and physeal contact. METHODS: A retrospective review was performed at a tertiary pediatric hospital from 2004 to 2020. Inclusion criteria consisted of patients treated surgically for histologically confirmed ABCs with a minimum of 6 months follow-up. Patients with treatment for a recurrent tumor or incomplete records were excluded. Patient demographics, location of the lesion, treatment technique, and incidence of recurrence were collected. Statistical analyses were performed using STATA. RESULTS: There were 129 patients (74 males and 55 females) with a mean age of 11.5 ± 4.1 years and an average follow-up of 29.0 ± 25.4 months. The most common locations for ABCs were the femur and tibia. Of the patients, 53.5% had tumors abutting the physis, 28.7% had no physeal contact, and 17.8% had insufficient imaging to evaluate physeal contact. Surgical adjuvants (high-speed burr, coagulation, liquid nitrogen, and/or hydrogen peroxide) were used in 91 of the 129 cases (70.5%). There was no significant difference in recurrence when comparing those who received an adjuvant and those who did not (25.3% vs 23.7%, P = 1.000). Physeal contact was also not significantly associated with recurrence ( P = 0.146). Finally, patients younger than 6 years old were significantly more likely to have recurrence compared with those 6 years old or older (66.7% vs 21.7%, P = 0.007). CONCLUSION: Our study found no association between the use of surgical adjuvants and the risk of recurrence after intralesional curettage for ABCs. Although our study did demonstrate that patients 6 years old or younger had an increased rate of recurrence, no significant association was found regarding physeal contact or sex. These data indicate that surgical adjuvant may not affect the recurrence rates of pediatric patients with ABCs. LEVEL OF EVIDENCE: Level III. This retrospective review compares rates of recurrence based on the choice of surgical adjuvant.

Aneurysmal bone cyst: Is selective arterial embolization effective as curettage and bone grafting?

INTRODUCTION: Aneurysmal bone cyst (ABC) is a lytic benign bone lesion representing about 1% of all primary bone tumors. Method to treat ABC's have developed over time. The standard of care cure for ABC has been curettage with or without bone grafting of the defect but is burdened by recurrence rates of approximately 25%-31%. Based on the assumption that ABCs usually supplied by one or more pathological feeding arteries, selective arterial embolization has been described as an adjuvant preoperative procedure to reduce intra-operative hemorrhage, and as primary treatment for lesions in difficult surgical access. In the current study, we therefore asked whether (1) a single or a repeat selective arterial embolization (SAE) for treating ABCs would produce comparable healing rates compared with curettage and bone grafting; (2) evaluated the relationship of recurrence in relation to the site of the cyst, the age, and gender of the patients; and (3) the two techniques differ in term of long-term complication. MATERIAL AND METHODS: We retrospectively reviewed 265 patients who underwent curettage and bone grafting or SAE performed at our institute from 1994 to 2018. The diagnosis of ABC was always established with percutaneous CT-guided biopsy or open biopsy. Patients were followed clinically with plain radiographs or CT scan at 3, 6, 9, and 12 months then annually in the absence of symptoms. Treatment success was determined evaluating pre- and postprocedural imaging according to Chang classification. RESULTS: Two hundred and nineteen were treated with curettage and bone grafting (curettage group), and 46 with SAE Group. Of the 219 patients treated with Curettage and bone grafting (curettage group), 165 out of 219 (75.3%) experienced bone healing, while local recurrence was observed in 54 cases (24.7%) after 12 months on average (range: 3-120 months) from surgery. After the first SAE, bone ossification was seen in 27 (58.7%), without needing any further treatment. Eleven recurred patients were treated with SAE (four patients need two while seven need three SAE to heal), and eight patients with curettage and bone grafting. Thirty-eight out of 46 (82%) patients experienced bone ossification regardless the number of SAE. The overall rate of local recurrence for all patients was 26.7%. SAE group presented a lower complication rate (6%) where two patients experienced skin necrosis, and one limb-length discrepancies (2% of all cohort). DISCUSSION: The use of SAE is an attractive option to treat ABC as it combines on one hand a lower complication rate than curettage and bone grafting, on the other it can be carried out in case of nonresectable ABCs, significantly reducing the size of viable ABC lesions, fostering bone remodeling and mineralization, and most importantly, significantly improving the patient's quality of life.

Management of advanced metacarpal aneurysmal cysts: Surgical technique.

The hand is a rare site for aneurysmal bone cysts (ABCs). Depending on their degree of invasiveness, treatment of ABCs ranges from medical therapy to surgical curettage and bone filling. In the most advanced cases, bone resection and reconstruction, with or without adjuvant or neoadjuvant treatment, are indicated. We describe a technique involving segmental bone resection and structural iliac graft reconstruction with carpo-metacarpal plate arthrodesis, for the management of advanced ABC involving the base of the metacarpals. The radio-clinical results of two patients operated on using this technique are presented, at 18 and 36 months. At the last follow-up, the results showed a QDASH of 15 and 10, and a PRWE of 9 and 11. Satisfaction was 10/10 in both cases. Grasp strength was 25 kg and 42 kg versus 28 kg and 40 kg on the opposite side. Pinch strength was 6 kg and 11 kg versus 7 kg and 10 kg. Metacarpophalangeal flexion was 80° and 90°. Extension was complete in both cases. Radiographs showed good graft fusion, with no lysis or signs of ABC recurrence at the last follow-up. Segmental bone resection and iliac autograft reconstruction with carpo-metacarpal plate arthrodesis represents a therapeutic option in the management of advanced ABCs of the metacarpal base.

Computed tomographic features and surgical treatment of equine mandibular aneurysmal bone cysts with ß-tricalcium phosphate in a multicenter case series.

OBJECTIVE: To describe clinical and imaging features and surgical treatment of equine mandibular aneurysmal bone cysts (ABCs) with ß-tricalcium phosphate (TCP). ANIMALS: 3 horses (cases 1, 2, and 3) and 1 pony (case 4) with histologically confirmed ABC. CLINICAL PRESENTATION: All cases had mandibular swelling with intact adjacent skin. Cases 1 to 3 had a body condition score of 3/5 and case 4 had 2/5 and showed quidding during mastication and, at oral examination, large interdental spaces and loose elements adjacent to the swelling. Radiography or CT was performed in all cases. In cases 1, 3, and 4, an expansile septate cystic space-occupying lesion with mass effect on the adjacent cortices and teeth was seen without compact bone destruction. Case 2 showed a heterogeneous osteolytic mass with multifocal cortical lysis and interruption. Case 4 had severe dental abnormalities of deciduous and precursors of permanent teeth. ABCs were surgically treated and filled with only TCP (case 3) or in combination with autologous bone marrow (cases 1, 2, and 4). RESULTS: Cases 1 through 3 showed an uneventful reduction in ABC size with increased opacity/attenuation. In case 4, a surgical site infection occurred. After removal of TCP remnants, the ABC healed satisfactorily, but remaining dental abnormalities necessitated dietary adjustments to maintain an acceptable body condition score. CLINICAL RELEVANCE: Treatment of ABCs with TCP had a favorable outcome and good long-term prognosis. In young specimens, the expansile effect on the development and eruption of neighboring teeth can influence and determine final functionality of the diseased dental quadrant.

Langerhans cell histiocytosis with aneurysmal bone cyst-like changes: a case-based literature review.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a neoplastic transformation of myeloid precursors that commonly presents as an osteolytic lesion of the long or flat bones in children. Aneurysmal bone cysts (ABC) are benign neoplasms that frequently affect the metaphysis of long bones and the spine, often revealing a rapidly expansile lesion with fluid-fluid levels. LCH with secondary ABC-like changes is a rare condition that has only been reported five times, with two presentations in the cranium. The aim of this paper is to review the etiology, clinical and radiographic presentations, and treatment of this condition, as well as to present a novel case on the topic. CASE DESCRIPTION: We describe a 5-year-old boy with a rapidly growing head mass and eye pain resulting in a diagnosis of LCH with secondary ABC-like changes. Radiography demonstrated an expansile, lytic lesion of the left parietal bone with fluid-fluid levels. A confirmatory diagnosis was made through histopathology, demonstrating an inflammatory, histiocytic infiltrate staining positive for CD1a, CD68, CD207 (Langerin), and S-100. The lesion was surgically excised, and the patient recovered without any complications. CONCLUSION: We present a novel case of LCH with secondary ABC-like changes managed with surgical excision. While a radiographic workup with multiple imaging modalities is helpful for diagnosis, a thorough immunohistochemical analysis is essential as imaging characteristics are variable and nonspecific. Furthermore, surgical excision should be considered first-line treatment for lesions involving the skull in surgically accessible areas as it is curative, alleviates symptoms, and allows for histopathological diagnosis.

Does the preoperative neutrophil-to-lymphocyte ratio have a prognostic value in aneurysmal bone cysts?

OBJECTIVES: The aim of this study was to evaluate the prognostic value of neutrophil-to-lymphocyte ratio (NLR), lymphocyte-tomonocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR) in aneurysmal bone cysts (ABCs). PATIENTS AND METHODS: Between February 2001 and August 2019, a total of 86 patients (44 males, 42 females; mean age: 21.5±15.2 years; range, 2 to 73 years) with a histologically confirmed diagnosis of ABCs who did not receive cancer treatment previously and had a minimum follow-up period of 24 months were retrospectively analyzed. Data including age, sex, side, tumor location, pre-treatment complete blood count analysis results, preferred surgical method, follow-up period, presence of recurrence, and date of recurrence were recorded. Preoperative NLR, LMR and PLR values were calculated in all patients. RESULTS: The mean follow-up was 56.7±13.5 (range, 24 to 179) months. Forty-one (47.7%) ABCs were located in the lower extremities, 36 (41.8%) in the upper extremities, and nine (10.4%) in the pelvic girdle. A statistically significant difference was detected in the NLR values according to recurrence status (p=0.023). The PLR and LMR values were not significant for area under the curve, while NLR values were significant for recurrence. The cut-off value was determined as 2.054. Those with an NLR of ≥2.054 were found to have a 4.561-fold higher risk of recurrence than those with an NLR of <2.054 (odds ratio [OR]=4.561). CONCLUSION: Our study results suggest that NLR, which is the pre-treatment inflammatory index, is a prognostic factor in patients with ABCs. Although NLR alone is not decisive in patients with elevated NLR, it can be used to evaluate the clinical prognosis and recommend an appropriate treatment strategy.

Secondary aneurysmal bone cyst of the frontal bone with fibrous dysplasia showing rapid expansion: a case report.

A 19-year-old woman presented with swelling of the left forehead without pain. She did not have any relevant past or family history. Computed tomography showed destruction of the outer cortex of the frontal bone. A solitary mass lesion with a fluid collection was detected with magnetic resonance imaging. Because the swelling of the left forehead had enlarged rapidly with osteolytic changes, surgical removal of the lesion was performed. The lesion appeared to be enveloped in a fibrous capsule. The soft lesion was removed from the frontal bone. The outer frontal bone was absent, although the inner frontal bone was preserved. Then, the frontal bone was resected with margins from the edge of the erosion. The dura mater under the lesion was intact. A cranioplasty was performed using titanium mesh. On histological examination, the trabecular bones revealed irregular shapes and arrangements, indicating fibrous dysplasia. There was a continuous high-cell-concentration pathological lesion outside the fibrous dysplasia. There were numerous cells, such as mononuclear cells, osteoclast-like multinucleated giant cells, foam cells, and red blood cells. The osteoclast-like multinucleated giant cells and other cells did not show significant nuclear atypia. Immunostaining with H3.3G34W was negative, and the ubiquitin-specific peptidase 6/Tre-2 gene showed no rearrangements. The histopathological diagnosis was secondary aneurysmal bone cyst with fibrous dysplasia. Additional postsurgical therapy was not performed. There has been no evidence of recurrence of the lesion for two years.

Giant cell tumor of bone with secondary aneurysmal bone cyst does not have a higher risk of local recurrence.

BACKGROUND: Fluid-fluid levels (FFLs) is found in 10%-16% of giant cell tumor of bone (GCTB), and the presence of FFLs raises the suspicion of GCTB with secondary aneurysmal bone cyst (ABC), which can lead to increased intraoperative bleeding and, blurring the operative field, be associated with a risk of local recurrence. The first objective of this study is to determine whether secondary ABC is associated with a higher risk of local recurrence after curettage in patients with GCTB of the extremities. The second objective of this study is to investigate the sensitivity, specificity, positive predictive value, and negative predictive value of the presence of FFLs detected on magnetic resonance imaging (MRI) to diagnose secondary ABC associated with GCTB. METHODS: Two hundred and eighty patients with GCTB of the extremities who underwent curettage at the authors' institutions between 1980 and 2021 were included in this study. RESULTS: Secondary ABC was found in 36 of 280 patients (12.9%) and local recurrence occurred in 66 of 280 patients (23.6%). Multivariate analysis showed no significant correlation between secondary ABC and local recurrence (hazard ratio [HR]: 1.87 (95% confidence interval [CI]: 1.00-3.53]; p = 0.051). Preoperative MRI revealed FFLs in 13 of 82 patients (15.9%). Sensitivity, specificity, positive predictive value, and negative predictive value of FFLs detected on preoperative MRI to diagnose secondary ABC were 36.8%, 90.5%, 53.8%, and 82.6%, respectively. CONCLUSION: The results of this study showed that secondary ABC does not increase the risk of local recurrence after curettage in patients with GCTB of the extremities. Although rare, FFLs were present in patients with GCTB and half of those with FFLs detected on preoperative MRI had secondary ABC.

Management of Calcaneal Cysts in the Pediatric Population: A Review.

Cysts of the bone are a common pathology that, although benign, are frequently treated because of their tendency to compromise the integrity of affected bone. Two common entities are unicameral bone cysts and aneurysmal bone cysts. Although these are two distinct pathologies, they are treated similarly and thus will be discussed in tandem. The optimal treatment of calcaneal bone cysts in pediatric patients has long been debated among orthopaedic surgeons because of the relatively small number of cases and varied results within the literature. Currently, there are three lines of thought regarding treatment: observation, injection, and surgical intervention. When considering which course of treatment is best for an individual patient, the surgeon must consider the fracture risk without treatment, the risk of complications with treatment, and the recurrence rate with each treatment approach. There are limited data on pediatric calcaneal cysts specifically. Still, there are much data concerning simple bone cysts of long bones in the pediatric population and calcaneal cysts in the adult population. Because of the lack of literature on the subject, there is a need for a review of the available literature and a consensus on the approach to treating calcaneal cysts in the pediatric population.

Allograft Versus Bioactive Glass (BG-S53P4) in Pediatric Benign Bone Lesions: A Randomized Clinical Trial.

BACKGROUND: Benign bone cysts in children have a high risk of recurrence after bone grafting. The optimal treatment and filling material for these lesions are currently unknown. METHODS: We compared cyst recurrence after intralesional curettage and filling with allograft versus bioactive glass (BG-S53P4; Bonalive) in a randomized clinical trial. The volume of recurrent cyst at 2-year follow-up was the primary outcome. RESULTS: Of 64 eligible children, 51 (mean age, 11.1 years) were randomized to undergo filling of the cyst using morselized allograft (26) or bioactive glass (25). Twelve (46%) of the children in the allograft group and 10 (40%) in the bioactive glass group developed a recurrence (odds ratio [OR] for bioactive glass = 0.79, 95% confidence interval [CI] = 0.25 to 2.56, p = 0.77). The size of the recurrent cyst did not differ between the allograft group (mean, 3.3 mL; range, 0 to 13.2 mL) and the bioactive glass group (mean, 2.2 mL; range, 0 to 16.6 mL, p = 0.43). After adjusting for the type of lesion (aneurysmal bone cyst versus other), bioactive glass also did not prevent larger (>1 mL) recurrent cysts (adjusted OR = 0.42, 95% CI = 0.13 to 1.40, p = 0.16). The Musculoskeletal Tumor Society score improved significantly (p ≤ 0.013) from preoperatively to the 2-year follow-up in both groups (to 28.7 for bioactive glass and 29.1 for bone graft). Four (15%) of the children in the allograft group and 6 (24%) in the bioactive glass group required a reoperation during the follow-up (OR for bioactive glass = 1.74, 95% CI = 0.43 to 7.09, p = 0.50). CONCLUSIONS: Filling with bioactive glass and with allograft in the treatment of benign bone lesions provided comparable results in terms of recurrence and complications. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Surgical Management and Denosumab for Aneurysmal Bone Cysts of the Spine in an Australian Tertiary Paediatric Centre.

Aneurysmal bone cysts (ABC) are rare osteolytic, benign but often locally aggressive tumours of the long bones or vertebrae. For spinal ABC, surgical management, embolisation or sclerotherapy alone often carry high morbidity and/or high recurrence rates. Interruption of receptor activator of nuclear factor-kappa B ligand (RANKL) signalling holds promise as an effective therapeutic strategy for these tumours. We aimed to review the approach to surgical management and evaluate the efficacy and safety of denosumab for ABC of the spine in children. Retrospective review of 7 patients treated with denosumab using a standardised protocol for ABC of the spine in a tertiary paediatric centre. Surgical intervention was only conducted if there was spinal instability or significant neurological impairment. Denosumab 70 mg/m2 was given 4-weekly for at least 6 months, followed by 2 doses of zoledronate 0.025 mg/kg, aiming to prevent rebound hypercalcaemia. All patients achieved stability of the spine and resolution of neurological impairment, if present. Six patients achieved metabolic remission and have ceased denosumab without recurrence to date; the other showed clinical and radiological improvement without complete metabolic remission. Three patients developed symptomatic hypercalcaemia 5-7 months after cessation of denosumab, requiring additional bisphosphonate treatment. We present our algorithm for the surgical and medical management of paediatric spinal ABC. Denosumab produced a radiological and metabolic response in all patients, with complete remission in most. Follow-up time was not long enough to evaluate the endurance of response after cessation in some patients. Incidence of rebound hypercalcaemia in this paediatric cohort was high, prompting a change to our protocol.