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.

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.

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.

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.

Differentiation of giant cell tumours of bone, primary aneurysmal bone cysts, and aneurysmal bone cysts secondary to giant cell tumour of bone: using whole-tumour CT texture analysis parameters as quantitative biomarkers.

AIM: To determine whether computed tomography (CT) texture analysis parameters can be used as quantitative biomarkers to help differentiate giant cell tumour of bones (GCTs), primary aneurysmal bone cysts (PABCs), and aneurysmal bone cysts (ABCs) secondary to giant cell tumours of bone (GABCs). MATERIALS AND METHODS: One hundred and seven patients with 63 GCTs, 31 PABCs, and 13 GABCs were analysed retrospectively. All patients underwent preoperative CT. Two radiologists independently evaluated the qualitative features of the CT images and extracted texture parameters. Patient demographics, qualitative features, and texture parameters among GCTs, PABCs, and GABCs were compared statistically. Differences in these parameters between ABCs and GCTs were also assessed. ROC curves were obtained to determine optimal parameter values. RESULTS: The best preoperative CT parameters to differentiate GCTs, PABCs, and GABCs included one qualitative feature (location around the knee) and four texture parameters (95th percentile, maximum intensity, skewness, and kurtosis). Age and three texture parameters (5th percentile, inhomogeneity, and kurtosis) enabled statistically significant differentiation between GCTs and ABCs. Combination of the above four parameters generated the largest area under the ROC curve (AUC) for the differentiation of GCTs and ABCs. CONCLUSION: CT texture analysis parameters can be used as quantitative biomarkers for preoperative differentiation among GCTs, PABCs, and GABCs.

Total en bloc spondylectomy of thoracic giant cell tumor with secondary aneurysmal bone cyst: case reports and review of literature.

Spinal giant cell tumor (GCT) combined with secondary aneurysmal bone cyst (ABC) is a locally aggressive primary bone tumor. Total en bloc spondylectomy has never been reported to treat thoracic GCT combined with secondary ABC. We retrospectively reviewed two cases of spinal GCT combined with secondary ABC. A 41-year-old male patient was presented with back pain due to irregular expansive bone destruction involving the T6 vertebral body and intraspinal space-occupying lesion. Total en bloc spondylectomy of T6 vertebra was performed with good neurological status after the surgery. A 29-year-old female patient was presented with right scapular region pain due to irregular expansive bone destruction involving the T5 vertebral body and intraspinal space-occupying lesion. Total en bloc spondylectomy of T5 vertebra was performed with good neurological status after the surgery. Adjuvant radiation therapy was applied after the surgery without local recurrence at the 12-month or 24-month follow-up. Spinal GCT combined with secondary ABC appears to have a high local recurrence rate. Therefore, total en bloc spondylectomy should be applied to treat thoracic GCT combined with secondary ABC.

A rare pediatric case of McCune-Albright syndrome with acute visual disturbance: Case report.

RATIONALE: McCune-Albright syndrome (MAS) is a rare disorder characterized by clinical findings, which includes fibrous dysplasia (FD). FD is a benign tumor that leads to increased rates of bone fracture. In some MAS cases with FD, facial deformities, severe pain, and orbital neuropathies are complicated. Aneurysmal bone cyst (ABC) is a benign bone tumor and rare complication of FD. PATIENT CONCERNS: A 9-year-old boy was admitted to our hospital because of acute visual disturbance. DIAGNOSIS AND INTERVENTIONS: The patient was clinically diagnosed as ABC complicated with MAS, and he underwent surgery. OUTCOMES: After the surgery, his sight became normal. Recurrence of ABC and visual disturbance was not observed in 3 years. Genetic analysis of a tissue sample from the ABC lesion by next-generation sequencing revealed a somatic activating GNAS mutation. LESSONS: To the best of our knowledge, this is the first case report of MAS causing optic neuropathy complicated with ABC. ABC complicated with MAS is extremely rare, but it should be considered as a possible diagnosis in patients with acute visual loss and facial swelling. In addition, our case had OAS, which is an uncommon syndrome and a rare complication in ABC with MAS, and rapid decompression of the ABC was effective in improving the patient's eyesight.

Rehabilitation of a child with a complicated aneurysmal bone cyst.

An aneurysmal bone cyst (ABC) is a benign lesion often found in long bones. Almost one third of ABCs are secondary to primary tumors. When found in the spine, ABCs can cause insidious back pain and, in rare cases, neurological deficits. This case will discuss an adolescent female who acquired a non-traumatic spinal cord injury (NTSCI) as a result of complications from an aneurysmal bone cyst. Treatment consisted of surgical removal of the cyst, laminectomy, corpectomy, and fusion of the thoracic spine. Following surgical intervention, the child spent several weeks in an acute inpatient pediatric rehabilitation facility. Goal oriented outpatient services facilitated further recovery and led to near complete resolution of symptoms associated with non-traumatic spinal cord injury. Contemporary and clinically oriented child and family interventions are essential in successful rehabilitation of children with NTSCI as a result of ABCs.

Surgical Excision of Thoracic Osteoblastoma with Secondary Aneurysmal Bone Cyst from a 12-Year-Old Child.

INTRODUCTION: Osteoblastoma is a primary benign tumour which commonly presents in the younger population during the second decade of life. However, more aggressive osteoblastomas may present with features of aneurysmal bone cyst, and these can occur at uncommon locations. CASE PRESENTATION: We report the case of a 12-year-old child having an osteoblastoma on the left side of T11 with secondary aneurysmal bone cyst presenting with neurological deficits and myelopathic symptoms. Surgical debulking of the lesion with decompression laminectomy and posterior instrumentation of the spine was performed. The child is currently recovering well with improvement of neurological deficits. DISCUSSION/CONCLUSION: Osteoblastoma with aneurysmal bone cyst of the thoracic spine is a rare condition with few reports in the literature, and surgical intervention with complete excision has been demonstrated here with recovery of neurological function.

Massive Post-traumatic Femoral Cyst Resulting in Pathologic Fracture in a Child: A Case Report.

CASE: A 10-year-old boy experienced a pathologic diaphyseal femur fracture through a large cyst encompassing 40% of femoral length. At age 5, he had had a traumatic ipsilateral diaphyseal femur fracture, treated with flexible nailing. Biopsy at age 10 revealed a simple bone cyst with components of aneurysmal bone cyst. Curettage, antegrade nailing, and allograft resulted in successful osseous healing. CONCLUSION: Post-traumatic cysts of long bones are rare and have not been reported to cause pathologic fracture in children. This case highlights that close scrutiny of follow-up radiographs of long bone fractures may identify clinically important post-traumatic cysts.

The Repair of an Acute Pathological Subtrochanteric Femur Fracture Using an Adult 3.5-mm Proximal Humerus Locking Plate in an Adolescent Patient: A Case Report.

CASE: We report a novel case of the successful repair of a pathological fracture of a 14-year-old boy's proximal femur using open reduction and internal fixation with an adult 3.5-mm proximal humerus locking plate. CONCLUSION: Successful repair of a pediatric pathologic femur fracture due to an aneurysmal bone cyst may be achieved using an adult proximal humerus locking plate in select patients.

Successful Intravascular Treatment of an Intraosseous Arteriovenous Fistula in Fibrous Dysplasia.

Fibrous dysplasia (FD) is a benign bone disease characterized by expansile lesions that typically stabilize with age. Rarely, FD can undergo malignant transformation, presenting with atypical, rapid growth and destruction of adjacent bone. Other potential causes of rapid FD expansion include secondary lesions, such as aneurysmal bone cysts. We describe a case of an aggressive occipital lesion that presented with pain associated with diplopia and tinnitus, raising concern for malignant transformation. A massive intraosseous arteriovenous fistula was identified giving rise to an anomalous vein coursing to the cavernous sinus with compression of the abducens nerve. The vascular anomaly was mapped and after embolization symptoms resolved; a biopsy with extensive genetic analyses excluded malignancy. The differential diagnosis for expanding FD lesions includes aggressive FD, malignant transformation, and secondary vascular anomalies. In cases when traditional radiographic and histologic assessments are nondescript, use of additional radiographic modalities and genetic analyses are required to make an accurate diagnosis and guide treatment. When vascular anomalies are suspected, detailed angiography with embolization is necessary to define and treat the lesion. However, to rule out malignant transformation, genetic screening is recommended.

Knee intra-articular extraskeletal aneurysmal bone cyst: a case report and review of literature.

Aneurysmal bone cyst (ABC) is a benign locally destructive lesion that usually developed in the bone cavity of bones, less commonly on the surface of cortical bones and very rarely develop outside the bone. There are only 35 reports of extraskeletal aneurysmal bone cyst (ESABC) in the English literature. We report a case of a 12-year-old female with no history of trauma who presented with knee pain. Imaging studies revealed an infrapatellar mass that was fast to calcify during a period of 3 months. MRI showed high T2 center, low T1 signal, and heterogenic enhancement with a rim of low intensity consistent with calcified boarders surrounded by severe soft tissue edema. The lesion was surgically excised, and a histological examination revealed an aneurysmal bone cyst possibly arising within myositis ossificans or heterotopic ossification. In her last follow-up 1.5 years after the surgical excision, the patient was symptom free and without signs of recurrence. To the best of our knowledge, this is the first reported case of an intra-articular ESABC located in the knee.

Total Calcanectomy and Bilateral Iliac Bone Autograft Reconstruction for the Treatment of Calcaneal Chondroblastoma Involving a Secondary Aneurysmal Bone Cyst: A Case Report and Literature Review.

Chondroblastoma is a rare, benign, cartilaginous-derived tumor accounting for ∼1% to 2% of all primary bone tumors and almost 9% of all benign bone tumors. In this case report, we describe a patient with chondroblastoma and a secondary aneurysmal bone cyst, with the adjacent talus being mildly affected. The initial diagnosis was giant cell tumor and was then confirmed after computed tomography-assisted biopsy. We performed a total calcanectomy via bilateral structural iliac bone autografting to relieve pain and reconstruct the loadbearing function because of the presence of extensive lesions. The patient was pain free and expressed satisfaction with postsurgical dorsiflexion and plantarflexion function at the 60-month follow-up visit. Radiographic images showed that the autografted iliac bone was completely healed, with no evidence of local recurrence.

Two cases of paralysis secondary to aneurysmal bone cysts with complete neurologic recovery.

DESIGN: Case report (retrospective). OBJECTIVE: These two cases of paralysis secondary to aneurysmal bone cysts (ABCs) demonstrated complete neurologic recovery following decompression and posterior spinal fusion. Although neurologic injury from ABCs has been described, information about the prognosis in the pediatric population is limited. METHODS: We review two cases of paralysis caused by ABCs in the thoracic spine in pediatric patients. RESULTS: Two patients (aged 12 and 13 years) presented to our emergency department with inability to ambulate and 0/5 strength in their lower extremities due to spinal cord compression from ABCs in their thoracic spine. Both patients had been unable to ambulate (case 1: nonambulatory for 2 weeks before presentation; case 2: nonambulatory for 1 week before presentation). The second patient also had loss of bowel and bladder control. They were managed with decompression and posterior spinal fusion. Both patients made complete neurologic recoveries. CONCLUSIONS: It is unclear whether age, chronicity of compression, or other factors contributed; nevertheless, the recovery in these two similar patients far exceeded initial expectations, especially in the case that presented as an American Spinal Injury Association Impairment Scale class A. LEVEL OF EVIDENCE: Level V.