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Rationale: Primary leiomyosarcoma of the bone (LMSB) is a rare aggressive sarcoma with limited treatment options. Histopathologic and immunohistochemical features are similar to their more common uterine and soft tissue counterparts. However, its broader spectrum of histopathologic features and rarity make diagnostic challenges., Patient Concerns: We present a case of LMSB in a 20-year-old female who presented with left shoulder aching pain for 3 months. An osteolytic intramedullary lesion was found in the left proximal humeral epi-metaphysis., Diagnoses: Initial open biopsy showed a giant cell tumor of bone with aneurysmal bone cyst (ABC)-like changes. However, an open biopsy followed by extended curettage showed LMSB with ABC-like changes., Interventions: Wide excision of the lesion and bipolar hemiarthroplasty followed by concomitant chemoradiation therapy was conducted. 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 encountered a rare case of LMSB. Most occurrences are in the lower extremity and trunk, respectively. ABC-like changes in bone tumors can lead to misdiagnosis. In this case, the ABC-like changes developed from the underlying LMSB as a secondary alteration. A careful examination of the underlying bone tumor is crucial to avoid misdiagnosing it as ABC or exhibiting ABC-like changes. Moreover, there has been no case report of LMSB with secondary ABC-like changes in bone., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: Giant cell-rich lesions are a diverse group of lesions that usually occur in bone and contain varying numbers of reactive osteoclastic-type multinucleate giant cells. These lesions present a challenge in pathologic diagnosis, often requiring a combination of clinical, radiographic, and histopathological assessments. The present retrospective observational study aims to provide a concise diagnostic criterion by combining all these parameters, which will aid in effective diagnosis and targeted treatment planning in the future., Material and Method: Previously diagnosed cases of these lesions were taken from the archives and categorized as Central Giant Cell Granuloma (CGCG), CGCG with secondary Aneurysmal Bone Cyst (ABC), primary ABC, and Brown's Tumour. Their demographic characteristics along with clinical, radiological, and histological data were retrieved and compiled into the table. The data was then analyzed and classified into aggressive and non-aggressive CGCG according to the criteria set in the study., Result: 10 reported cases were of isolated CGCG, 5 were CGCG with secondary ABC, 5 of Brown's tumor and 3 were that of conventional ABC. Out of these, the lesions showing extensive size along with an increased number of giant cells were categorized under aggressive CGCG, whereas those with less aggressive characteristics were categorized under non-aggressive CGCG. The aggressive category comprised 5 cases of isolated CGCG, 2 cases of CGCG with secondary ABC, 3 cases of primary ABC, and 5 of brown tumor, whilst the rest of the cases were categorized under non-aggressive CGCG., Conclusion: Since all these share overlapping features, thereby this type of concise categorization is the dire need so that the lesions can have a precise diagnosis with treatment and follow-up intervals for aggressive lesions., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: A soft tissue aneurysmal bone cyst is an extremely rare tumor. The objective of the article is to present the clinical, radiological, and histopathological features of a very unusual neoplasm of soft tissues., Case Report: A 13-year-old male patient presented a painful, mobile, and rapidly growing mass on the posteromedial aspect of his left knee. Imaging studies revealed a mass that arose from the medial surface of the distal sartorius muscle, with extension to the subcutaneous fat tissue. It was a well-circumscribed solid tumor with a peripheral rim calcification on plain film, computerized tomography, and ultrasound (zonal phenomenon). On magnetic resonance imaging, a heterogenous mass on T1-weighted images (WI) and T2-WI was seen, with a peripheral hypointense rim in both sequences. An outstanding edema on T2-WI extending to the soft tissue and muscles of the medial compartment of the knee was detected. The mass was resected, and the "tumoral mimickers" histopathological and molecular (next-generation sequencing) diagnoses confirmed a soft tissue aneurysmal bone cyst. A follow-up showed that the patient was free of disease 12 months after surgery., Conclusion: Soft tissue aneurysmal bone cyst is a rare tumor. Appropriate clinical and radiological correlation should be performed to differentiate it from other tumor mimickers., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

An aneurysmal bone cyst (ABC) is a benign bone neoplasm that typically occurs during the first and second decades of life. ABC usually presents as a rapidly growing intramedullary expansile mass with multiple blood-filled cysts in the metaphysis of the long tubular bones. Here, we report a case of a periosteal solid ABC that was initially diagnosed as a high-grade surface osteosarcoma. A 10-year-old male was referred to our hospital for swelling and tenderness of the left upper arm. Radiography revealed periosteal mass without fluid-fluid levels. On performing open biopsy, the tumor showed hypercellular proliferation of uniform spindle to epithelioid cells with brisk mitotic activity (up to 12/2 mm 2 ) and lace-like osteoid formation, which was diagnosed as a high-grade surface osteosarcoma. After one course of chemotherapy using adriamycin and cisplatin, peripheral sclerosis was conspicuous, which led to pathological review and revision of diagnosis as "possibly osteoblastoma." The patient was disease-free for 4 years after marginal resection and curettage. Retrospective nanopore DNA sequencing unexpectedly detected a PAFAH1B1::USP6 rearrangement. The fusion gene was further validated using reverse transcription-polymerase chain reaction and the diagnosis was revised to ABC. Chromothripsis involving chromosome 17 has also been identified. Methylation analysis classified the present tumor as an ABC or non-ossifying fibroma using t-distributed stochastic neighbor embedding and unsupervised hierarchical clustering. This case report highlights the utility of nanopore DNA sequencing for soft tissue and bone tumor diagnosis., (© 2024 Wiley Periodicals LLC.)

Background: Juvenile Psammomatoid Ossifying Fibroma (JPOF) is a type of noncancerous bone tumor that usually affects adolescents in the craniomaxillofacial area. Clinical manifestations are usually symptoms caused by the tumor's invasive compression of surrounding tissues. Aneurysmal Bone Cyst (ABC) is also a benign bone tumor, and it typically occurs in long bones and the spine. Only 2% to 3% of cases occur in the head and neck. Due to the rarity of this combination of clinical cases, clinicians face difficulties in comprehensively understanding this complex lesion. Therefore, a comprehensive review of the clinical manifestations and characteristic imaging findings is necessary for surgeons., Case Presentations: On April 6, 2019, a 13-year-old boy presented with left maxillofacial bulge and pain for 1 month. Magnetic resonance imaging of the paranasal sinuses showed an irregular hive-like mass signal in the left maxillary sinus, and cystic changes with fluid levels were seen in the lesion. After the initial diagnosis of JPOF with primary ABC, we decided to perform a facial mid-facial resection of maxillary sinus tumor to remove the tumor tissue. Finally, after 3 recurrences and 4 operations, there was no tumor recurrence for 20 months after the last operation, and the patient was still under continuous follow-up., Conclusions: This case provided a reference for the diagnosis and treatment of JPOF combined with ABC. In particular, a new understanding of the association between the two diseases and the management of recurrence were proposed, which had the potential to improve clinical understanding of this complicated condition., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

This case report describes an aneurysmal bone cyst in the maxilla of a young dog. It describes the clinical presentation, diagnostics, management, and successful outcome of this highly unusual case. Bone cysts are described as benign, cavitated lesions within bone that are lined by reactive tissues. There is no epithelial lining in the lesions. Bone cysts usually contain hemorrhage or serosanguinous fluid. They usually appear in the long bones, and present as a swelling with or without pain., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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., (© 2023 The Authors. Journal of Surgical Oncology published by Wiley Periodicals LLC.)

Aneurysmal bone cysts (ABCs) are rare benign vascular bony lesions mostly encountered in young patients. These cysts can occur as primary lesions or, less frequently, secondary to other pathologies such as osteoblastomas. Skull ABCs are rare and can extend intracranially, presenting with hydrocephalus and bleeding. Here we illustrate the case of a 9-year-old male who presented with headache, nausea, and vomiting, without neurological deficit. Radiological investigations showed a soap-bubble lesion with mass effect over the right cerebellum. The patient underwent right sub-occipital craniotomy with marginal wide resection of the cystic lesion. The patient had excellent outcomes. The histopathological report was consistent with osteoblastoma with an aneurysmal bone cyst., (Copyright: © Neurosciences.)

Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.

Purpose: Aneurysmal bone cyst (ABC) of the orbit is a very rare tumor, occurring mostly in the pediatric population, and can result in sight threatening complications and disfigurement. This review discusses previously reported cases with a focus on evolving treatment options and molecular genetics., Methods: We report the youngest case of an orbital ABC with a confirmed gene fusion: a 17-month-old girl, with confirmed FGFR-UPS6 (Fibroblast Growth Factor Receptor 1-ubiquitin specific peptidase 6/tre-2). A literature search for relevant publications on the topic was performed via Medline and PubMed, with the appropriate data extracted., Results: Thirty-two cases of orbital aneurysmal bone cyst were identified in the literature. Presentations are varied and can include pain, proptosis, decreased vision, and extraocular motility disturbance. Typical imaging and histopathology findings are discussed, in particular the usefulness of identifying USP6 gene arrangements. Treatment modalities are reviewed including surgery, embolization, and receptor activator of nuclear factor kappa-B ligand (RANKL) inhibitors. Recurrences can occur, usually within 2 years., Conclusions: Orbital ABC is a neoplasm that presents unique diagnostic and treatment challenges. Gene rearrangements can confirm primary ABC and rule out other underlying pathology. Disfigurement and sight threatening complications can occur due to both the disease process and with treatment. Outcomes may be improved with the use of systemic therapy., Competing Interests: The authors have no financial or conflicts of interest to disclose., (Copyright © 2022 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

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.

Background: Aneurysmal bone cysts are expansile benign lesions associated with compressive destruction and obscure pathogenesis. The most common sites of temporal bone involvement are the petrous apex, squamous portions and mastoid., Case Report: This paper reports a right temporal aneurysmal bone cyst in a 51-year-old man who presented clinically with facial palsy, and hearing loss and impaired vestibular function. Magnetic resonance imaging and computed tomography findings were consistent with a diagnosis of aneurysmal bone cyst. Inter-operative findings showed that the lesion had caused compressive damage to the internal auditory canal. Following surgical excision, the patient experienced vertigo, indicating recovery of vestibular function. Follow-up imaging revealed complete resection without clinical recurrence., Conclusion: To our knowledge, this is the first report of aneurysmal bone cyst invasion of the inner auditory canal. Our clinical experience indicates that vestibular nerve damage recovery is relatively uncommon. This case report will hopefully inform future studies.

Purpose of Review: Aneurysmal bone cysts are rare, locally aggressive bone tumors. Optimal treatment of ABCs is still matter of debate as therapies including sclerotherapy, selective arterial embolization and systemic treatment with denosumab are increasingly utilized, in addition to or instead of traditional curettage. The purpose of this review is to discuss current concepts and difficulties in diagnosing and treating primary ABCs, based on latest available literature., Recent Findings: In diagnostics, multiple new fusion partners of USP-6 have been described on next-generation sequencing specifically for primary ABCs. In a recent systematic review, failure rates of percutaneous injections and surgery were comparable. In a literature review, the use of denosumab seemed effective but resulted in multiple cases of severe hypercalcemia in children., Summary: Accurately diagnosing primary ABC is crucial for treatment decisions. Curettage remains a valid treatment option, especially with adjuvant burring, autogenous bone grafting and phenolization. Percutaneous sclerotherapy represents a solid alternative to surgery, with polidocanol showing good results in larger studies. Systematic therapy with denosumab exhibits favorable results but should be reserved in the pediatric population for unresectable lesions, as it may result in severe hypercalcemia in children. When selecting a treatment option, localization, stability and safety should be considered., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Aneurysmal bone cysts are benign bone tumors that not uncommonly involves the spine. However, this involvement can cause scoliosis, albeit rarely. This report focuses on the importance of proper management for complete tumor resection to prevent recurrence and spinal deformity., Case Presentation: A 12-year-old Middle Eastern boy, with a history of T11 aneurysmal bone cyst resection and bone grafting carried out at another hospital, presented with spine deformity of 4 months' duration. The deformity was not associated with pain or neurological deficit. A whole-spine magnetic resonance imaging with contrast confirmed the recurrence of the aneurysmal bone cyst. Posterior spinal instrumentation with corpectomy of T11 was then performed, and confirmed with histopathology the recurrence of aneurysmal bone cyst. Two years post-corpectomy, deformity correction was done from T5-L4., Conclusion: Management of aneurysmal bone cysts requires meticulous planning and full excision to prevent recurrence, especially in the growing spine. If neglected, it can cause major spinal deformities and cord compression, which places a medical burden on the patient and family. To avoid such complications, treating aneurysmal bone cysts along with scoliosis correction can prevent deformity progression., (© 2022. The Author(s).)

Aneurysmal bone cyst is a type of benign bone pathology with expansile and osteolytic features whose etiology remains unclear. Graves' disease is an autoimmune disease characterized by diffuse goiter and hyperthyroidism. Moyamoya disease is a progressive cerebral vasculopathy. It has been reported that Graves' disease and Moyamoya disease share a similar etiology involving cytokines and autoimmune and genetic factors. There are no previous reports regarding the relationship between aneurysmal bone cyst and Graves' disease. Here, we present the rare case of a 25-year-old woman with suspected aneurysmal bone cyst of the left proximal femur and a definite preoperative diagnosis of Graves' disease, in whom lesion resection combined with left total hip replacement was indicated. Biopsy confirmed the diagnosis of aneurysmal bone cyst. Three days postoperatively, the patient developed acute ischemic cerebral infarction owing to Moyamoya disease, which was subsequently confirmed. This case elucidates the potential interaction among aneurysmal bone cysts, Graves' disease, and Moyamoya disease and provides lessons regarding appropriate perioperative preparation for patients with Graves' disease who require surgery to avoid potential severe complications.

Osteoclastic giant cells represent a common cellular component of lesions arising in bone. Highlighting this morphological finding, the current WHO classification of bone tumors defines a diagnostic group comprising aneurysmal bone cyst, giant cell tumor of bone and non-ossifying fibroma, which may display morphologic similarities while being distinct with regard to molecular and biological features. Starting with these tumors - putting a focus on lesions arising in bone - this article gives a survey of other (chondrogenic and osteogenic) tumors that frequently contain osteoclastic giant cells, which may, particularly in small biopsies, enter differential diagnosis. Overlapping features with selected giant cell-containing soft tissue tumors, which may be of differential diagnostic relevance in daily routine, are discussed., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The use of denosumab to treat giant cell tumors of bone (GCT) and other giant cell-containing bone tumors has become more common. While the clinicopathologic features of denosumab-treated giant cell tumors of bone have been well-illustrated, descriptions of other denosumab-treated bone tumors are very limited. Surgical pathology files of two institutions and consultation files from two authors were searched for denosumab-treated aneurysmal bone cysts and denosumab-treated osteoblastomas. Clinicopathologic features were reviewed and analyzed. We identified four patients with denosumab-treated bone tumors other than GCT from our surgical pathology and consultation files, including two aneurysmal bone cysts and two osteoblastomas. All were treated with denosumab for 0.5-7.0 (median 4.5) months. Radiologically, denosumab-treated tumors showed decreased size with increased ossification and mineralization on CT and heterogeneous intermediate to hypointense signal on MRI. Histologically, denosumab-treated aneurysmal bone cyst contained thin, elongated, curvilinear, and anastomosing strands of bone with empty lacunae, while denosumab-treated osteoblastoma showed circumscribed nodules of woven bone lined by small osteoblasts. Denosumab-treated aneurysmal bone cyst and osteoblastoma showed treatment-related morphologic changes that can mimic other bone neoplasms. Their recognition requires correlation with the clinical history of denosumab use and radiologic findings., (© 2022 Scandinavian Societies for Medical Microbiology and Pathology.)

The aneurysmal bone cyst (ABC) is a benign, blood-filled bony lesion that notoriously affects the vertebral column and long bones of the body. Rarely, ABCs can manifest in the head and neck (HNABC). The purpose of this paper is to provide a comprehensive review of existing literature on HNABC. This review includes: case reports and case series on ABCs manifesting in the head and neck region published in the English language. All cases identified via PubMed were analyzed individually. Articles were included according to specified eligibility criteria. The total number of cases analyzed were 72 (39 case reports; 33 case series). The average age at the time of HNABC diagnosis was 19.1 years (range: 0.42-62 years). The ratio of prevalence by gender affected exhibited an even 1:1 male-to-female split. CT in combination with MRI proved to be the most prevalent imaging modality utilized (37.2%). HNABC was most commonly detected in the mandible (37.1%), followed by the sinus (14.3%) and cranium (11.4%). The most frequently employed single treatment modality was surgical excision (94.1%). 94.4% of patients were alive with no evidence of disease at follow-up, while 5.6% of patients exhibited disease at follow-up. The average follow-up period was 3.59 years (range: 0.17-17.0 years). Aneurysmal bone cyst of the head and neck region is a rare condition that should be considered in the differential diagnosis of bony, vascular lesions presenting in the aforementioned locations. Since aneurysmal bone cyst of the head and neck region can present as a rapidly growing, expansive and destructive lesion, it is crucial that clinicians are aware of this entity so that patients are accurately diagnosed and treated., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

This report describes osteoblastoma of the temporal bone found on a well-child visit. The relevant clinical, radiographic, and histologic features are described. The tumor was completely resected via a transtemporal approach. The differential diagnosis for these tumors include osteoma, giant cell tumor, histiocytosis, aneurysmal bone cyst and sarcoma. Histologic findings are critical for determining the proper diagnosis., (Copyright © 2021, Otology & Neurotology, Inc.)

Aneurysmal bone cyst is a benign bone neoplasm that most commonly arises from the metaphyses of long bones in the first and second decades of life. Here, we describe a case of an aneurysmal bone cyst that occurred in the distal tibial diaphysis of a 72-year-old female that was concerning for malignancy on imaging, demonstrating cortical breakthrough and soft tissue extension. Histologically, the tumor showed the characteristic morphologic features of aneurysmal bone cyst. Fluorescence in situ hybridization was positive for USP6 rearrangement, and RNA sequencing revealed a USP6 gene fusion with VDR, a novel partner that encodes the vitamin D receptor and that has not been implicated previously in human neoplasia. This case highlights the diagnostic challenges presented by aneurysmal bone cyst in elderly adults, and it expands the genetic spectrum of USP6 rearrangements., (© 2021 Wiley Periodicals LLC.)

The term giant cell-rich tumors of bone refers to a shared morphologic pattern in a group of different osseous lesions, that is, the abundance of osteoclastlike giant cells. Fitting with a broad spectrum of clinical presentations and biological behavior, the recent detection of characteristic molecular alterations in giant cell tumor of bone (H3-3), nonossifying fibroma (KRAS, FGFR1), giant cell granuloma of the jaws (KRAS, FGFR1, TRPV4), and aneurysmal bone cyst (USP6) have contributed significantly to the biological understanding of these morphologically related but clinically distinct lesions and their systematic classification, highlighting differences and pathogenic relationships., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: The aneurysmal bone cyst is a rare benign but aggressive osteolytic tumor for which there is still no ideal treatment, the reports on treatment by sclerotherapy in the pediatric population are scarce and in our region even less. The objective is to communicate the experience of the treatment of aneurysmal bone cyst with polydocanol 3%., Material Y Methods: Retrospective, descriptive and cross-sectional study. Period: June/2017 to June/2021. Inclusion: patients with histological diagnosis of aneurysmal bone cyst; Under general anesthesia and fluoroscopic guidance, intralesional puncture with 16G needle was performed through which 3% polydocanol was slowly administered. Data: medical history. Quantitative variables shall be expressed in measures of central tendency and dispersion; qualitative variables shall be expressed as frequencies or percentages., Results: Nine consecutive patients were included, all of whom had pain and tumor in one of the extremities. Gender: 3 female and 6 male. Age: median 10.5 years (range: 2-15.1). Weight: median 32.8 kg (range: 11-44.5). Total procedures: 44; procedures per patient: mean 4.9 (SD: ± 2.0). Procedure time: mean 33.9 minutes (SD: ± 18.3); radiation: mean 1.34 mGy (SD: ± 1.55). Hospitalization: one day, except one patient. Complications: skin damage in one case, no recurrences follow-up: 12 to 50 months., Conclusion: In this pediatric series, polydocanol 3% was useful and effective for the treatment of aneurysmal bone cyst, with few complications. One disadvantage is that it requires several sessions and in addition, no significant difference has been demonstrated between other forms of treatment in terms of the recurrence rate.

Aneurysmal (ABC) and simple bone cysts (SBC) have been traditionally distinguished by radiological and histopathological features. However, there is some radiological and histopathological overlap between ABC and SBC. ABC is characterised by USP6 fusions while, recently, NFATC2 fusions have been found in a large proportion of SBC. Identifying these fusions may assist in confirming the diagnosis of either ABC or SBC. To elaborate the potential benefit of molecular testing, we report a prospective series of 19 consecutive bone cysts with comprehensive radiological, histopathological and molecular diagnostics. Integrating radiological, histopathological and molecular findings, 11 cysts were diagnosed as SBC and 8 as ABC. Radiologically, 6 of 11 SBC and 6 of 8 ABC were diagnosed as ABC. Fibrin-like collagen deposits were identified in 8 of 11 (73%) SBC and 3 of 8 (38%) ABC. Nodular fasciitis-like areas were identified in 6 of 8 (75%) ABC and in 7 of 11 (64%) SBC. A USP6 fusion was identified in all 8 ABC, including a novel RBM5-USP6 fusion. An NFATC2 fusion was found in 7 of 11 SBC (FUS-NFATC2 fusion in 5 and EWSR1-NFATC2 in 2 cases). There is radiological and histopathological overlap between SBC and ABC in a significant proportion of cases. A diagnosis of ABC is frequently suggested radiologically in SBC, and fibrin-like deposits, thought to be specific for SBC, may be found in some ABC. Molecular testing may significantly improve diagnostic accuracy in bone cysts., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective/hypothesis: Aneurysmal bone cysts (ABCs) are benign, lytic bone lesions, which rarely present in the paranasal sinuses. There is no published consensus on the appropriate diagnostic or treatment approach. Our objective was to elucidate the clinical behavior, treatment, and outcomes for patients with ABCs of the paranasal sinuses (psABCs)., Study Design: Retrospective case series and system review of the literature., Methods: A retrospective chart review was performed to identify patients evaluated at the authors' institution with psABC and consolidated with literature reports of psABC., Results: Eighty-nine patients met inclusion criteria. The most common presenting symptom was painless facial swelling (n = 35, 39%). The ethmoid sinuses were the most common site involved (n = 55, 62%). Surgical approach was reported in 74 cases including 20 endoscopic and 54 with an open or combined approach. Fifty-nine patients (71%) underwent gross total resection. Follow up data was reported for 67 patients. Fifteen patients (22%) were found to have recurrence or progression at follow up; 10/15 (66%) patients within the first 12 months, 14/15 (93%) within the first 24 months, and 1/15 (7%) greater than 24 months after treatment. Patients were more likely to have recurrence/progression if they presented with nasal discharge (P = .05), proptosis (P = .01), or orbital involvement (P = .03)., Conclusions: psABCs typically present with painless swelling or nasal obstruction. Orbital involvement is a negative prognostic indicator with these patients more likely to have recurrence after treatment. Recurrence or progression of disease is most likely to occur within 2 years after treatment. Therefore, patients should be monitored closely during this time., Level of Evidence: 4 Laryngoscope, 131:E2525-E2533, 2021., (© 2021 The American Laryngological, Rhinological and Otological Society, Inc..)

Aneurysmal bone cysts (ABCs) arising from vascular malformation are extremely rare, and none have been reported in the literature in English till now. We report a very rare case of secondary ABC of left temporal bone in a 5-year-old Caucasian boy who presented with a left sudden facial palsy associated with a painless non-tender mass of the left temporo-parietal region. The computed tomography (CT) and magnetic resonance imaging (MRI) features were suggestive of ABC secondary to a capillary venous malformation, with concurrent involvement of the squamous, mastoid, and petrous portions of the temporal bone. Surgical resection was performed. On follow-up, the patient was found to be doing well.

Background: Chondroblastoma (CB) is a rare, primary, benign bone tumor that commonly affects men aged 15-20 years. It is usually detected in the epiphysis of the long bones, such as the proximal femur, humerus, and tibia. The patella is an infrequent site. CB with secondary aneurysmal bone cyst (ABC) is extremely rare in the patella, which can be easily confused with other common bone tumors of the patella. Thus, it is necessary to make the right diagnosis to get a good outcome., Case Presentation: We have presented here the case of a 30-year-old man who was suffering from anterior knee pain for the past 6 months that had aggravated 2 weeks before the presentation. Osteolytic bone destruction in the patella could be detected in both his X-ray and computed tomography (CT) examinations, while the magnetic resonance imaging (MRI) detected a fluid level. Accordingly, secondary ABC was presumed. We diagnosed the condition as giant cell tumor (GCT) with secondary ABC and, accordingly, performed curettage inside the focus region with autogenous bone grafting following the patient's medical history, physical manifestations, results of physical and ancillary examinations, and the disease characteristics. However, the intraoperative and postoperative outcomes indicated that the patient's histopathology was consistent with that of typical CB, suggesting a definitive error in diagnosis. Accordingly, the patient was finally diagnosed with patella CB along with secondary ABC., Conclusions: Past studies have demonstrated that the 3 commonest bone tumors affecting the patella are GCT, CB, and ABC. CB with secondary ABC can be easily misdiagnosed as GCT with secondary ABC or ABC. Performing incision biopsy or excision biopsy and conducting histological examination may be the most effective method for suspected CB with secondary ABC.

Aims: USP6 rearrangement underpins self-limiting fibroblastic/myofibroblastic neoplasms, including nodular fasciitis (NF), myositis ossificans (MO), aneurysmal bone cyst (ABC), and related variants. The aim of this study was to characterise UPS6 and fusion partners in order to delineate the clinicopathological, genetic and bone-forming features in such lesions of soft tissue (ST)., Methods and Results: Break-apart fluorescence in-situ hybridisation (FISH) validated USP6 rearrangement in 31 of 35 NF [comprising three of three fasciitis ossificans (FO) cases, seven of eight cellular variant of fibroma of tendon sheath (C-FTS), four of six MO, three of three ST-ABC, and two of two fibro-osseous pseudotumours of digits (FOPD)]. As determined with FISH and reverse transcription polymerase chain reaction, MYH9-USP6 was the commonest fusion in four C-FTS and 20 NF, including one intravascular case and two infantile (one retroperitoneal) cases. The presence of MYH9-USP6 confirmed the diagnosis of two NFs> 50 mm with prominent ischaemic necrosis. COL1A1-USP6 was predominant in ossifying lesions, including all FO, MO, ST-ABC and FOPD with identified partner genes, and was also present in non-ossifying head and neck NF (HN-NF) and C-FTS in two cases each. A cervical NF of a 14-month-old girl harboured the novel COL1A2-USP6. Ossifying lesions showed considerable genetic and morphological overlaps. Sharing COL1A1-USP6, FO and FOPD showed similar central or haphazard bone matrix deposition. Besides zonation of outward bone maturation, four COL1A1-USP6-positive MO had incipient to sieve-like pseudocysts reminiscent of ST-ABC., Conclusion: MYH9-USP6 is present in some C-FTS and most NF, including rare variants, but is unrelated to bone formation. All bone-forming USP6-rearranged lesions adopt COL1A1 as the 5' partner, indicating close genetic kinships. However, COL1A1/COL1A2 also contributes to the pathogenesis of minor subsets of non-ossifying USP6-rearranged HN-NF and C-FTS., (© 2020 John Wiley & Sons Ltd.)

Competing Interests: The authors have no financial or conflicts of interest to disclose.

Aneurysmal bone cyst (ABC) is a rare, benign but locally aggresive bone tumor of unknown origin tumor. It commonly affects children and usually occurs at the metaphysis of long bones. Scapula is a very rare location and ABCs of the scapula have been sparsely described in the literature. Differential diagnosis can be challenging as it shares common radiological and clinicopathological features with other benign and malignant bone tumors. The degree of diagnostic difficulty increases even more when an unusual tumor site has to be taken into account. Here, we describe rare and challenging cases of a primary ABC located at the scapula that was surgically treated. This is the first case report of ABC involving the scapula in adult patient.

Background/aim: Aneurysmal bone cyst is a benign bone lesion with a strong tendency to recur. The rearrangement of chromosome band 17p13/USP6 gene is now considered a characteristic genetic feature of aneurysmal bone cyst, with t(16;17)(q22;p13)/CDH11-USP6 as the most frequent chromosomal aberration/fusion gene. We report a novel variant translocation leading to a new fusion gene in an aneurysmal bone cyst., Materials and Methods: Genetic analyses were performed on an aneurysmal bone cyst found in the tibia of a child., Results: G-banding chromosome analysis yielded the karyotype 46,XX,t(12;17)(q21;p13)[5]/46,XX[2]. FISH analysis with a USP6 break-apart probe showed rearrangement of USP6. RNA sequencing detected LUM-USP6 and USP6-LUM fusion transcripts which were subsequently verified by RT-PCR/Sanger sequencing. The two genes exchanged 5'- non-coding exons. Thus, promoter swapping between USP6 and LUM had taken place., Conclusion: We report a novel t(12;17)(q21;p13) chromosome translocation which gave rise to a LUM-USP6 fusion in an aneurysmal bone cyst., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

The solid variant of aneurysmal bone cyst (SVABC) is very uncommon and frequently misdiagnosed. We reevaluated and summarized the clinicopathologic features of 17 SVABCs and further discussed the use of this nomenclature to differ SVABCs from extragnathic giant cell reparative granuloma (GCRG) in the setting of the USP6 rearrangement era. The immunohistochemical markers included α-SMA, SATB2, AE1/AE3, Ki67, S100, CD68 and P63. USP-6 status was detected by fluorescence in situ hybridization using a break-apart probe. The 17 patients with SVABCs comprised 10 males and 7 females ranging in age from 4 to 70 years. The involved locations included the long bone (n = 11), hand (n = 4), rib (n = 1) and vertebra (n = 1). The lesions were characterized by proliferated spindle cells with scattered giant cells and hemorrhages with variable positive α-SMA, SATB2, CD68 and Ki-67 expression. All patients had USP6 rearrangements without H3F3A glycine 34 mutations. Our study reveals that SVABC shares similar clinical and histologic features with other bone lesions, which may lead to an erroneous diagnosis. The presence of an USP-6 rearrangement contributes to the diagnosis SVABC; SVABC and most of the previously documented extragnathic GCRGs may be considered within the umbrella of primary aneurysmal bone cysts., (© 2020 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

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., (Copyright © 2019 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Aneurysmal bone cysts associated with tubular bones of the hand are rare and even rarer in the paediatric age-group. They are rapidly growing, destructive benign bone tumors. Multiple treatment modalities for aneurysmal bone cyst have been reported in the literature, but controversy exists regarding optimal treatment. We report a case of aneurysmal bone cyst of proximal phalanx of middle finger in a 2 year old child treated at our tertiary care hospital. The diagnosis was confirmed with pre-operative MRI, FNAC and post-operative histopathology. Curettage of the lesion and autologous bone grafting was performed. The hand was immobilized in a short below elbow slab for 4 weeks followed by physiotherapy. Excellent radiological and functional outcomes were obtained with no recurrence at a 5 year of follow up.

Background: The aneurysmal bone cyst (ABC) is a rare osteolytic lesion that is often associated with osseous disease such as fibrous dysplasia (FD)., Case Description: A 66-year-old woman previously diagnosed with FD presented with suddenly reduced visual acuity. Computed tomography and magnetic resonance imaging revealed a large osteolytic lesion in the middle cranial fossa that had invaded the left orbit. Although its radiological findings were compatible with an ABC, rotational digital subtraction angiography revealed that this osteolytic lesion was a large middle meningeal artery (MMA) aneurysm. To release the compression force on the optic nerve and confirm the diagnosis, we performed endovascular embolization, followed by surgical removal of the lesion. Histologic examination revealed that the resected lesion met the requirements of a thrombosed aneurysm. No new neurologic deficits appeared after the surgery, and no symptomatic recurrence have been noted during the 6-month follow-up., Conclusions: This is the first case report to show that ABC-like lesions in patients with FD could be thrombosed MMA aneurysms. It is thus possible that some lesions previously diagnosed as ABCs were thrombosed MMA aneurysms or included a thrombosed MMA aneurysm. It is therefore important to rule out the presence of a MMA aneurysm when we encounter what appears to be an ABC in the presence of FD., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Metastatic breast cancer in the bone rarely has a cystic appearance, and while it is common in the orbit, its metastasis to the orbitotemporal skull is rare. Consequently, it is difficult to diagnose it. We report and discuss a rare case of metastatic breast cancer with simple cyst appearance in the orbitotemporal region of the skull., Case Description: A 63-year-old woman presented with mild double vision only on left gaze that lasted for 2 months. Ten and a half years ago, the patient underwent surgery for tumor resection of a stage 3 breast adenocarcinoma, followed by radiotherapy and administration of anticancer therapy. Thereafter, she continued hormonal therapy with antiestrogen drugs, which was discontinued a half year ago because there was no recurrence during treatment. On admission, magnetic resonance imaging (MRI) showed a single and simple cystic lesion in the orbitotemporal region of the skull. The cyst was filled with fluid of different intensity, indicative of a hemorrhagic component. Additional gadolinium-contrasted MRI showed no enhancing effects in the lesion. The cyst was totally removed by surgery, and the histologic examination confirmed the diagnosis of breast adenocarcinoma. Intensity-modulated radiotherapy was then administered, and the patient started follow-up hormonal therapy with antiestrogen agents. No recurrence in the orbitotemporal region of the skull occurred during 6 months after the surgery., Conclusions: Metastatic breast cancer should be considered in the differential diagnosis even if it appears as a simple cyst in the orbitotemporal bone after long-term remission., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Aneurysmal bone cyst (ABC) is a benign tumour whose progression involves the RANK/RANKL signalling pathway. Surgery is the reference standard treatment but carries risks that vary with the site of the tumour. Denosumab is a human monoclonal IgG2 antibody that targets the RANK/RANKL pathway and may therefore hold promise for inhibiting ABC progression. The objective of this study was to evaluate denosumab use in paediatric patients (younger than 18 years) with ABC and to describe the clinical and radiological outcomes, as well as the side effect profile., Hypothesis: Denosumab is a viable option in children with ABC refractory to standard treatments., Material and Methods: We retrospectively reviewed the medical files of paediatric patients given denosumab to treat ABC in any of 32 centres affiliated with the French Paediatric Cancer Society (Société Française du Cancer de l'Enfant, SFCE) and French Sarcoma Group (Groupe Sarcome Français, GSF-GETO). We identified 5 patients treated between March 2015 and June 2018. Median age was 8 years (range, 7-17 years). Pain was a symptom in all 5 patients and neurological deficits were present in 3 patients. Surgery was performed in 4 patients, either before (n=3) or after (n=1) denosumab therapy; the remaining patient had no surgery. Denosumab was given as monthly injections in a dosage of 70mg/m 2 for a median of 12 months (range, 4-23 months). The clinical outcomes and changes in computed tomography and/or magnetic resonance imaging findings were evaluated., Results: Abnormalities in calcium and phosphate levels secondary to the ABC occurred in 2 patients. At median of 24 months (range, 0-28 months) after denosumab initiation, all 5 patients were free of pain, and the neurological deficits in 3 patients had improved. Central remineralisation and cortical reconstitution were demonstrated consistently by the imaging studies., Discussion: Denosumab is a viable treatment option in selected paediatric patients with inoperable ABC. The immediate adverse effect profile is acceptable. A larger study with a longer follow-up would be welcome to further assess the contribution of denosumab to the treatment of ABC., Level of Evidence: IV., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Goals: Ubiquitin specific protease 6 ( USP6 ) gene rearrangement has been reported in approximately 70%-75% of aneurysmal bone cyst cases. We hypothesize that fluorescence in situ hybridization (FISH) testing of this marker will be useful in the pathological differentiation of primary aneurysmal bone cyst (ABC), secondary ABC, giant cell tumor of bone (GCT), and telangiectatic osteosarcoma (TOS) which are morphologically similar. This study aims to evaluate the efficacy of this test and validate it for diagnostic use., Procedures: FISH was performed in primary ABC, secondary ABC, GCT and TOS using dual color USP6 gene break apart probes. The sensitivity, specificity, positive predictive value, and negative predictive values were calculated., Results: Primary ABC demonstrates USP6 rearrangement. All secondary ABC, GCT and TOS were negative. The test sensitivity and specificity in primary ABC were 53% (9/17) and 100% (18/18), respectively. The positive predictive value and negative predictive value were 100% (9/9) and 69% (18/26), respectively., Conclusion: The USP6 gene break apart detected by FISH is validated as a novel diagnostic tool for primary ABC in our laboratory. This test could be used to study the predictive value of USP6 targeted therapy for primary ABC in the near future., (© 2019 by the Association of Clinical Scientists, Inc.)

Primary aneurysmal bone cyst (ABC) is a benign multiloculated cystic lesion of bone that is defined cytogenetically by USP6 gene rearrangements. Rearrangements involving USP6 are promoter swaps, usually generated by fusion of the noncoding upstream exons of different partner genes with exon 1 or 2 of USP6, thus leading to transcriptional upregulation of full-length USP6 coding sequence. Testing for USP6 rearrangements is used diagnostically to distinguish it from secondary ABC and other giant cell-rich primary bone tumors. In this report, we present a case of a 16-year-old male with a primary ABC of the left distal femur. USP6 break apart fluorescence in situ hybridization was positive for a rearrangement and conventional chromosome analysis identified a reciprocal X;17 translocation. In order to identify the putative USP6 fusion partner, we performed RNA sequencing and uncovered a novel USP9X-USP6 promoter swap fusion. This result was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and by mate pair sequencing thus showing the utility of these alternative methodologies in identifying novel fusion candidates. Ubiquitin-specific protease 9X (USP9X), like USP6, encodes a highly conserved substrate-specific deubiquitylating enzyme. USP9X is highly expressed in a number of tissue types and acts as both an oncogene and tumor suppressor in several human cancers. We conclude that oncogenic activation of USP6 via USP9X promoter exchange represents a novel driver of primary ABC formation., (© 2019 Wiley Periodicals, Inc.)

Objective: The aim of this study was to define histopathological features of giant cell tumor of bone, especially accompanying fibrohistiocytic or aneurysmal bone cyst like components, in the light of our institutions experience., Methods: A total of 120 cases (64 females and 56 males; mean age: 36.2 (12-80)) with 'GCT' diagnosed between the years 1996-2016 were included in this retrospective analysis. Cases were evaluated according to clinical features such as age, gender, localization, recurrence, metastasis and histopathological features., Results: Tumors were localized most frequently at proximal tibia and distal femur, respectively. In 11 cases areas rich in fibrohistiocytic component and in 20 cases aneurysmal bone cyst like component were observed. In 2 cases both components were present. Twenty three cases recurred. In 1 case which was primarily located at calcaneus, tumor metastasized to lung 4 years later during follow-up., Conclusion: GCT can be confused with other tumor or tumor-like lesions involving giant cells. Secondary changes such as fibrohistiocytic or aneurysmal bone cyst-like components and coagulation necrosis were frequently seen in conventional giant cell tumor of bone. For tumors having prominent fibrohistiocytic and/or aneurysmal bone cyst-like components, in order to detect characteristic areas representing GCT, additional sampling is essential. Although secondary histopathological changes do not appear to affect clinical outcome, these features are important in differential diagnosis. Approximately one fifth of GCT cases show recurrence and sacrum and foot bones were the most frequent sites for recurrence., Level of Evidence: Level IV, diagnostic study., (Copyright © 2018 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.)

Introduction: Aneurysmal bone cysts (ABCs) are rare, rapidly expansile, benign, vascular lesions capable of causing local bone destruction. The majority of cases present as multi-cystic lytic lesions (with solid-variant ABCs representing<10% of all presentations) of the long bones or vertebrae, rarely occurring in the head/neck region., Clinical Case: A 44-year-old female presented with nine days of worsening pain, ptosis and proptosis in the right eye. CT and MR imaging revealed a 3.2cm extra-axial multiloculated right frontal lobe mass in the orbit with fluid-fluid levels secondary to layering of solid blood components. A right craniotomy was performed and the lesion was resected piecemeal with subsequent high speed burring to remove residual tissue. Histological evaluation revealed spindle and giant cell infiltration of the bone without vascular channels. Based on these findings, the lesion was diagnosed as a solid-variant orbital ABC without paranasal sinus involvement. The patient recovered fully with no residual symptoms., Conclusion: This case report details a rare presentation of ABC (solid-variant presenting outside of the vertebrae/long bones) with discussion concerning possible treatment modalities and guidance for follow-up., (Published by Elsevier Masson SAS.)

The aneurysmal bone cyst is a benign rare tumor, which usually develops during childhood and its more often found in limbs. The most accepted treatment consists in curetagge and filling with graft. However, certain locations may be inaccesible for surgery and represent therapeutical challenges. We present the case of an 11 year-old male patient with limping and right hip pain without any traumatic nor infectious record. In the image studies with CT and MRI a lytic and expansive lession was found in the upper part of the right acetabulum and right iliac wing, all of which suggested an aneurysmal bone cyst with an associated acetabular fracture. A biopsy was performed which confirmed the diagnosis. He was treated with a CT-guided embolization and, due to its size, curetagge and allograft filling afterwards. He was asymptomatic after1 year of follow-up.