Search

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.)

Purpose: Osteoid osteoma occasionally occur in the spine, but their malignant transformation is not common. We present an extremely rare case of the malignant transformation of an osteoid osteoma to high-grade osteosarcoma that formed in the pedicle and spread to the lateral mass of the cervical spine., Case Presentation: We report the case of an 18-year-old man who suffered from neck pain as an initial symptom. The size of the radiolucent lesion was 12 mm in diameter at the time of diagnosis. Intralesional tumour resection and autologous bone grafting were performed. The remaining tumour grew gradually for 40 months after the surgery; therefore, the tumour had grown rapidly till 51 months after the initial diagnosis. At this stage, the tumour size was approximately 6-fold larger than the initial size, and resulted in progressive paraplegia. A biopsy revealed that the tumour had transformed into a high-grade osteosarcoma. Heavy charged particle irradiation was performed to control tumour growth., Conclusions: There is a possibility of malignant transformation of osteoid osteoma. Patients with osteoid osteoma or osteoblastoma should be carefully observed, especially for recurrent tumours after an intralesional resection.

Spinal osteoblastoma is rare clinically, with insidious onset, atypical symptoms, and various imaging manifestations, which can easily lead to misdiagnosis and delayed diagnosis. It can cause severe neurological dysfunction in patients with intermediate to advanced stages and may easily recur after surgery. Imaging examinations such as radiography, computed tomography, magnetic resonance imaging, and positron emission tomography have different value for the diagnosis of spinal osteoblastoma, but they lack specificity. The preferred treatment is surgical resection, which is technically difficult, and in some cases, osteoblastoma cannot be completely removed. New clinical approaches such as radiofrequency ablation, radiotherapy, targeted chemotherapy, and other comprehensive treatments have emerged and are progressing rapidly, but no unified norms have yet been developed. This manuscript provides a systematic review of the literature and provides an extensive and comprehensive review of this rare tumor in terms of multimodality imaging manifestations and clinical progress., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Benign osseocartilaginous tumors of the spine are overall uncommon, representing between 1 and 13% of all primary bone tumors and less than 10% of all spinal tumors. Tumors in this category include osteoblastic lesions such as the related osteoid osteoma and osteoblastoma, and cartilage-forming lesions including osteochondroma, chondroma, and chondroblastoma. Aneurysmal bone cysts, giant cell tumors of bone, and eosinophilic granulomas also comprise benign tumors of the spine arising from bone. There is significant heterogeneity in the epidemiology, molecular biology, imaging features, and optimal treatment of these lesions. For example, osteoid osteoma is characterized by high expression of the cyclooxygenase enzymes, making it amenable to treatment with anti-inflammatory drugs initially, whereas other lesions such as osteoblastoma may require intralesional curettage or en bloc resection sooner. Generally, en bloc resection is preferred when possible to minimize risk of recurrence. Further, some tumors may arise in the setting of syndromic conditions, such as multiple chondromas arising in Ollier disease or Maffucci syndrome, or as part of genetic disorders, such as osteochondromas in the context of hereditary multiple exostosis. These lesions may present with local pain, cause neurological compromise or be discovered incidentally on routine imaging. The Enneking classification and Weinstein-Boriani-Biagini system are routinely used to classify lesions and assist in surgical planning. More novel techniques such as radiofrequency ablation and laser photocoagulation have been applied for the treatment of osteoid osteoma and may have utility in the treatment of other lesion types. A multidisciplinary approach is critical in the management of benign lesions of the spine, and both chemotherapeutic and surgical approaches are routinely used., (© 2023. Springer Nature Switzerland AG.)

Background: The aim of this study was to evaluate the results of different treatments for pelvic Osteoblastoma (OB)., Methods: We retrospectively evaluated 34 patients affected by primary pelvic OB from 3 oncologic referral centers. Patients with a minimum follow-up of 24 months were included. Local recurrence (LR) rate and complications were recorded., Results: The primary treatment was radio-frequency ablation (RFA) in 4 patients (11.8%), curettage (ILC) in 21 (61.7%) and resection (EBR) in 9 (26.5%). Mean follow-up was 8.9 years (SD ± 6.6). Local recurrence free survival (LRFS) rate after primary surgery was 79.4% at 3 and 5 years. In details, LRFS rate at 3 and 5 years was 50.0% in RFA, 81.0% in ILC and 88.9% in EBR. Post-operative complications occurred in 6/34 patients (17.7%), in particular after EBR., Conclusions: RFA is the least invasive technique to treat OB but with high LR rate. Thus, it should be reserved to very small lesions. ILC is a suitable treatment for stage II OB. For stage III OB, EBR is the treatment of choice, despite an increased risk of complications. For selected stage III OB (relatively small, periacetabular area) ILC might be considered., Competing Interests: Declaration of competing interest All the Authors have no conflict of interests to declare., (Copyright © 2021 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Osteoblastoma is a rare benign bone tumour. It represents 1% of all primary bone tumours. Common locations are the vertebral column and long bones of the extremities. Although well documented in craniofacial locations, only occasional case reports describe orbital involvement. The authors present a case of a fronto-orbital osteoblastoma which posed a significant diagnostic dilemma. Despite early local recurrence, the molecular findings were supportive of a benign lesion.

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.)

Epithelioid osteoblastoma, sometimes equated with aggressive osteoblastoma, is a variant of osteoblastoma that typically demonstrates more worrisome imaging and pathological features compared to conventional osteoblastoma. These more aggressive features can overlap with those seen in osteosarcoma, creating a diagnostic challenge for radiologists and pathologists. Recent identification of FOS and FOSB gene rearrangements in osteoid osteoma and osteoblastoma has allowed for greater diagnostic confidence following biopsy, but careful radiological-pathological correlation remains a key component for guiding appropriate management. Although the imaging features of conventional osteoblastoma have been previously described, there are limited examples in the literature of the imaging appearance of epithelioid osteoblastoma, and none with secondary aneurysmal bone cyst. In this case report, we detail the clinical, imaging, and histological characteristics of a proximal femoral epithelioid osteoblastoma which was pathologically confirmed by FOS and FOSB genetic testing. The initial imaging impression favored a malignancy, but when the biopsy results were correlated in a multidisciplinary fashion with the imaging, epithelioid osteoblastoma became the leading diagnosis which was subsequently genetically confirmed. This case emphasizes the value of multidisciplinary radiology-pathology correlation in routine practice., (© 2021. ISS.)

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.)

Introduction: Aggressive osteoblastoma (AO) represents a rare tumor with borderline features between benign osteoblastoma and osteosarcoma. Having a local aggressive behavior without metastasizing attitude, radical excision is a mainstay treatment. Conversely, spine fusion technique is still debated. We report a rare case of cervicothoracic junction (CTJ) AO and the tailored decision-making process to choose the best treatment., Case Presentation: A 34-year-old man complaining of neck pain was admitted to our department. Cervicothoracic MRI revealed a well-circumscribed lesion involving C7 left lamina with cortical erosion and mild spinal canal invasion. Additionally, STIR sequences exhibited a bright signal spreading through the posterior third of the C7 and T1 vertebrae which on T1-weighted and T2-weighted sequences appeared isointense and hyperintense, respectively. Therefore, the patient underwent a C7 laminotomy. Histology revealed an aggressive variant of osteoblastoma. Therefore, tumor was classified as AO and surgical management was reconsidered. A combined anterior and posterior approach was recommended to reach oncological radicality and spinal stability. At 6-years follow-up, patient remained neurologically intact without signs of recurrence and/or of instability., Discussion: Due to its rarity and mimicking features, diagnosis of AO results challenging. Due to its aggressive behavior, radical surgery is the mainstay treatment. Conversely, the most suitable fusion technique is still debated. A proper surgical management should be focused on oncological radicality to guarantee the total tumoral removal avoiding progression or recurrences. Similarly, a proper evaluation of the long-term spinal balance should be assessed to avoid developing of spinal deformities or instrumentation failures., (© 2021. The Author(s), under exclusive licence to International Spinal Cord Society.)

Osteoblastoma of the skull is a rare entity, and they account only for 2-4% of all the cases of osteoblastoma. We perform a comprehensive review of the pertinent literature on the subject and we report a case of a 3-year-old girl presenting with a 6-month history of a supraorbital mass and exophthalmos due to an osteoblastoma of the frontal and ethmoid bones involving the orbit and anterior skull base. A 3D printed model of the patient's skull was used for the preoperative planning and reconstruction strategy. Total en-bloc resection of the tumor followed by immediate reconstruction was achieved. No recurrence was detected 3 years after the surgery. Gross total resection is strongly advised with skull osteoblastoma, especially in young age, because of the risk of the recurrence and malignant transformation. 3D printing is proven to be a valuable tool to enhance surgical performance by avoiding complications while achieving total resection with accurate reconstruction. Long-term follow-up is important to detect recurrences and improve the management of these young patients., (Copyright © 2020 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Camurati-Engelmann disease (CED) is a rare, progressive diaphyseal dysplasia characterized as diaphyseal hyperostosis and sclerosis of the long bones. Corticosteroids, bisphosphonates, and losartan have been reported to be effective systemic medications used to reduce CED symptoms. There are no reports of osteoblastoma in patients with CED, and osteoblastoma in the distal radius is rare. We present a patient diagnosed with CED, based on radiological and histological examinations, at 11 years old. At 22 years old, she experienced severe pain in her right forearm and was treated with bisphosphonate, losartan, and prednisolone; however, the pain continued. An expansive and sclerotic lesion at the distal radius was observed on radiography. A follow-up plain radiograph indicated that the lesion was growing. Fluorodeoxyglucose positron emission tomography revealed solitary, intense radiotracer uptake, and a biopsy and surgical resection were performed due to suspected malignancy. Pathologic analysis showed anastomosing bony trabeculae rimmed by osteoblasts observed in a loose fibrovascular stroma. The lesion was diagnosed as an osteoblastoma. Following bone excision and artificial bone grafting, the patient's severe pain almost completely disappeared. At final follow-up, no evidence of osteoblastoma recurrence was noted. To our knowledge, this is the first case report of osteoblastoma arising in a patient with CED. Bone excision and artificial bone grafting may be a treatment option for local symptomatic osteoblastoma in patients with CED.

Case: A 25-year-old man presented with progressive pain and swelling of the left foot for 4 years. The images showed a contrast-enhanced mixed lesion (osteolytic and blastic) of the first metatarsal bone with surrounding soft-tissue edema. The differential diagnoses favored chronic osteomyelitis or neoplasia, most likely benign. Histopathology confirmed the diagnosis of osteoblastoma as immature bone trabeculae rimmed by osteoblasts appeared. Then, the patient was successfully treated with wide surgical excision of the first metatarsal bone and reconstruction using a nonvascularized fibular autograft. After 3 years of follow-up, the graft was well incorporated and no recurrence was encountered., Conclusion: Osteoblastoma is rare in metatarsals; only 12 cases have been reported. It may have similar clinical and radiological picture to osteomyelitis. Wide surgical excision followed by fibular autograft reconstruction is an effective treatment option., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B425)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Primary benign osseous tumors and tumor-like lesions at the sacrum are rare in the pediatric population and exact surgical strategy is still unclear. In this study, we evaluate the outcome for pediatric patients with benign tumors and tumor-like lesions at the sacrum who were receiving surgical treatment according to our proposed surgical strategy and classification., Methods: We analyzed 49 pediatric patients with sacral benign tumors or tumor-like lesions aged 18 years and below from 2005 to 2018. There were 23 men and 26 women with a mean age of 14.0±3.8 years. Nineteen patients had giant cell tumors (GCTs), 9 aneurysmal bone cysts, 5 osteoblastomas, 5 neurogenic tumors, 3 hemangiomas, 3 teratomas, 2 Langerhans cell histiocytosis, 1 chondroblastoma, 1 fibrous dysplasia, and 1 GCT of tendon sheath. We proposed our surgical plan and surgical classification for pediatric patients with sacral benign tumors or tumor-like lesions., Results: The mean follow-up duration was 6.2 years (range, 1.0 to 18.9 y). GCTs (39%, 19/49) and primary aneurysmal bone cysts (18%, 9/49) are the top 2 common histologic types. Preoperative selective arterial embolization (SAE) was performed in 12 cases and 24 patients received intraoperative aortic balloon occlusion (ABO) as the preoperative surgical plan. Furthermore, according to tumor location at the sacrum, we classified surgical excision of sacral benign tumors and tumor-like lesions into 3 types. Fourteen cases were classified as type I, 27 as type II, 3 as type III, and 5 patients with neurogenic tumors cannot be classified into this surgical classification. Ten patients had wound complications. Two had femoral artery thrombosis because of ABO application. One had mechanical failure. Rate of local recurrence was 16%. Seven patients with GCTs and 1 with neurogenic tumor had local recurrence. No patient died of disease at the last follow-up. For the assessment of neurological function, the rate of neurological dysfunction was 12% (6/49). Four cases had urinary incontinence, 3 fecal incontinence, and 3 had bowel obstruction. Next, univariate analysis for influence of preoperative SAE and intraoperative ABO on complications demonstrated that both of them exerted no significant influence on the occurrence of oncological and nononcological complications., Conclusions: The proposed surgical strategy can provide an excellent therapeutic effect for pediatric benign tumors and tumor-like lesions at the sacrum. Preoperative SAE and intraoperative ABO can safeguard pediatric patients with high vascularity of benign tumor at the sacrum during the operation., Level of Evidence: Level IV., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Case report., Objective: To report the clinical and imaging findings of a patient with the extremely rare association of aneurysmal bone cyst and osteoblastoma in the cervical spine. To our knowledge, only three cases have been reported in the published literature in children under 16 years of age with this condition in the cervical spine., Methods: The patient's history, physical examination, imaging findings, and management with a complete 4-year medical history, surgical intervention and radiological follow-up are reported., Results: A 4-year 11-month-old boy was diagnosed with aneurysmal bone cyst in association of osteoblastoma and was treated with CT-guided intralesional injection calcitonin and methylprednisolone. During the course of intralesional therapy, a pathological fracture of C2 was produced. Subsequently, a widened intralesional excision and instrumented fusion from occiput to cervical spine (C0-C4) was performed., Conclusion: The association of aneurysmal bone cyst and osteoblastoma in spine is extremely rare. Although both are benign lesions, in the cervical location, complete removal of the tumors is challenging. Wide resection with reconstruction of the segments for stability associated with adjuvant treatment with calcitonin and corticosteroids provides a good option.

Abstract: Osteoblastoma is a benign bone tumor with a slow growing and local aggressive nature. This tumor type is usually localized in the cervical vertebra and rarely involves laryngeal cartilage structures. Very few osteoblastoma cases have been reported in the literature. Here we present laryngeal osteoblastoma originating from arytenoid cartilage in a patient with a history of cordectomy due to glottic squamous cell carcinoma., Competing Interests: The author reports no conflicts of interest., (Copyright © 2020 by Mutaz B. Habal, MD.)

Osteoblastoma is a rare benign osteoblastic tumor accounting for less than 1% of all bone tumors; approximately 10% to 12% of cases occur in the maxillofacial skeleton. This case report describes the clinical, imaging, and histopathologic findings of an atypical osteoblastoma occurring in the mandible of a 60-year-old man. The characteristics of the lesion and the differential diagnosis from other bone pathoses are reviewed., Competing Interests: The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

Osteoblastoma is a relatively rare, benign, bone-forming tumor, commonly observed in the second and third decades of life. Spine and the long tubular bones are the most common sites of involvement. Osteoblastoma is infrequently seen in other sites, including the bones of hand and foot. A rare case of a 35-year-old man that presented an osteoblastoma of the cuboid bone is reported. The patient was treated with surgical resection and grafting. After the intervention, the patient recovered with no clinical and radiological evidence of recurrence after one year of follow-up. Several cases of osteoblastoma-like variant of osteosarcoma of the cuboid have been previously reported, but, to our knowledge, this is the first case of conventional and isolated osteoblastoma involving the cuboid bone reported in the literature., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this article is to introduce and share our experience in the sequential use of a novel guiding plate system for accurate mandibular reconstruction via transoral approach and evaluate its clinical effects., Methods: Ten patients were operated with transoral mandibulectomy and simultaneous mandibular reconstruction using a novel guiding plate system. Postoperatively, aesthetic assessment and quantitative evaluation were analyzed by measuring the parameters like discrepancy in osteotomy lines, mandibular similarity and symmetry. The independent samples t-test was used and P < 0.05 was considered as significant., Results: All patients underwent planned transoral surgical procedure successfully. The postoperative aesthetic assessment was rated as excellent. The discrepancy between virtual and actual osteotomy lines, at anterior and posterior regions was 0.80 ± 0.08 and 0.98 ± 0.37 mm, respectively. The postoperative evaluation revealed that mandibular similarity was 0.85 ± 0.03, coronal mandibular angle (CMA) 0.66 ± 0.40, axial mandibular angle (AMA) 1.97 ± 1.25, and sagittal mandibular angle (SMA) 1.97 ± 1.05. There was statistically significant difference in the mean values of osteotomy line discrepancy, mandibular similarity and symmetry, among novel guiding plate and traditional plate groups., Conclusions: The novel guiding plate system is a viable and easy-to-use technology for improving the surgical outcomes in patients requiring transoral mandibulectomy and simultaneous mandibular reconstruction by overcoming the problem of limited access due to the presence of lips and cheeks. This can highly improve the precision in osteotomy, fixation of the prebent titanium reconstruction plate, spatial relation transfer, and achieving better symmetry and similarity of mandibular contour., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Benign and malign tumors can affect the temporomandibular joint (TMJ) as any other articulation. Nevertheless, TMJ tumors are rare and mostly benign. Their clinical expression is varied including symptomatology similar to TMJ dysfunctional disorders, otologic or neurologic pathologies. In some cases, they remain totally asymptomatic. Hence, diagnosis is difficult since the symptomatology can be misleading with TMJ dysfunctional disorders or otologic disorders wrongly diagnosed. There is thus frequently a long delay between symptoms onset and diagnosis. The great variety of TMJ lesions explains the wide range of possible treatment modalities, mostly based on surgery. We provide here a review of the lesions originating from the TMJ. Tumoral or cystic mandibular lesion affecting the TMJ through local extension will not be discussed. Osteoma, osteoid osteoma, osteoblastoma, chondroma, osteochondroma, chondroblastoma, tenosynovial giant cell tumors, giant cell lesions, non-ossifying fibroma, hemangioma, lipoma or Langerhans cell histiocytosis are all possible diagnosis among the benign tumors found in the TMJ. Pseudotumors include synovial chondromatosis and aneurysmal bone cyst. Finally, malign tumors of the TMJ include mainly sarcomas (osteosarcoma, chondrosarcoma, synovial sarcoma, Ewing sarcoma, and fibrosarcoma), but also multiple myeloma and secondary metastases. We will review the clinical, radiological and histological aspects of each of these lesions. The treatment and the recurrence risk will also be discussed., (Copyright © 2020 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: Osteoblastoma is a benign, aggressive and rare osteoblastic tumor. Its most common location is in later elements of the spine and sacrum. The cuboid presentation is exceptional., Case Report: A 50-year-old male who began her condition in 2005, with pain and increased volume in the dorsolateral region of the middle foot. X-rays show bone grafting and a cuboid lesion, radiotransparent, heterogeneous, multilobed, with irregular edges that exceeds the lateral cortical. Angiotomography was performed where hypervascularized injury was observed; bone scan showed uptake of technetium 99, and MRI reported an injury with post-surgical, cystic and multilobed changes. Trans surgical biopsy was taken, increased atypia-free cellularity and few multinucleated giant cells were reported and Enneking 2 qualified. Treatment was initiated with resection of the tumor, cryotherapy, and placement of tricortical graft in the bone defect. He exhibited good post-surgical evolution. At three years of the surgical procedure, he's without tumor and asymptomatic. Although osteoblastoma does not usually occur in cuboid, it should be taken into account as a differential diagnosis., Conclusion: Bone tumors, despite having common locations, can occur in rare areas and therefore the complete radiographic and histopathological clinical study in each patient is critical.

Background: Reports of osteoblastic tumours are limited to a few case reports in veterinary medicine. Osteoblastoma-like osteosarcoma has been accepted by the World Health Organization as an intermediate form between an osteosarcoma and osteoblastoma. This type of tumour indicates an osteosarcoma, that may resemble osteoblastoma clinically, histologically, and radiologically and have the capability for metastasis. Osteoblastoma-like osteosarcoma has not been described in veterinary medicine so far., Case Presentation: An eight-year old cat was presented due to progressive ataxia and paraparesis of the pelvic limbs. Imaging confirmed a well-defined, extradural mass originating from the spinous process of the second thoracic vertebra (T2) leading to severe compression of the spinal cord. Decompressive cytoreduction was achieved by removal of the mass after dorsal laminectomy of T1. After recovering from an acute worsening 3.5 weeks after surgery, the cat had an improved neurological status and the dorsal compression was resolved at follow-up 8 months later. A focal contrast enhancing lesion was still evident at the base of T2 spinous process and lung metastasis was additionally suspected. Based on histopathological, radiographic, and clinical features, an "osteoblastoma-like osteosarcoma" was suspected., Conclusions: To the best of our knowledge, this is the first description of this tumour in veterinary medicine. In addition, this case report highlights the difficulty in the diagnosis and definition of osseous neoplasia in cats and provides a literature review.

Osteoblastoma is a rare nonfibroblastic osteoid tissue-forming primary bony tumor usually arising in the medullary cavity/diploic space of any bone. The calvarium is an extremely rare site of its origin. Clinically, 2 types of osteoblastoma are noted: benign/conventional/typical and aggressive/high grade. Their imaging features are nondifferentiating and nonspecific, histopathologic features have a few subtle but nonspecific differences, and they have highly distinct clinical behavior. We report an extremely rare case of a patient with large aggressive cranial osteoblastoma, who developed massive inoperable multifocal recurrence 15 months after total en bloc resection with wide margins. A concise review of cases of aggressive osteoblastomas involving the cranium available in the English literature is also presented as an update., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Osteoblastomas are locally aggressive bone tumors typically affecting the posterior elements of the vertebral column. The treatment of choice is total surgical resection, traditionally through an open laminectomy, often with facetectomy and fusion when the lesion is in the foramen., Objective: To seek an alternative to open surgery, allowing quick and full functional recovery, to meet the youth and athlete population's specific surgical goals. In this population especially, open surgery can be associated with significant impairment and morbidity., Methods: We report a pediatric case of posterior L5 osteoblastoma completely removed using a facet-sparing and fusion-avoiding contralateral foraminal minimally invasive approach using a tubular retractor system. A 12-yr-old male competitive tennis player presented with progressive right L5 lumbosciatica. Computed tomography scan and magnetic resonance imaging revealed a lesion of the right L5 pedicle, facet, and vertebral body with significant foraminal soft-tissue extension. Being unfit for percutaneous radiofrequency ablation, the patient underwent a minimally invasive biopsy and resection using an 18-mm-wide METRx nonexpandable tubular retractor (Medtronic) through a contralateral approach, sparing the facet and avoiding fusion surgery., Results: Postoperative imaging showed residual tumor. The patient was reoperated in a similar fashion with complete tumor removal. His symptoms resolved completely postoperatively. He resumed tennis within 4 mo and remains symptom- and tumor-free at 12-mo follow-up., Conclusion: Minimally invasive contralateral facet-sparing resection of a pediatric lumbar osteoblastoma is an alternative to standard technique and is associated with significant advantages for young athletes, such as quick and full functional recovery, along with avoidance of fusion when the facet joint is involved., (Copyright © 2020 by the Congress of Neurological Surgeons.)

A 37-year-old man presented with a 2-year history of left hip pain. Pretherapeutic imaging demonstrated a 4 cm osteoblastoma located in the intertrochanteric region of the proximal femur, surrounded by extensive bone marrow edema. After multidisciplinary meeting, percutaneous cryoablation was decided and performed under computed tomography guidance using three cryoprobes to match the exact size and shape of the tumor, resulting in complete resolution of symptoms. Magnetic resonance imaging follow-up demonstrated resolution of the bone marrow edema pattern and ingrowth of fat at the periphery of the ablation zone consistent with long-term healing of the tumor.

Osteoblastoma is an uncommon primary bone tumor. Its occurrence in the cranial vault is extremely rare. We here report our first case of right parietal bone osteoblastoma in a 46-year old woman with a history of benign cranial traumas. She reported progressive painful, non-inflammatory right parietal bone swelling. Craniocerebral CT scan showed hyperdense bone lesion with sparing of the internal table of the right parietal bone. The patient first underwent biopsy, then complete resection of the bone lesion with methyl-methacrylic cement cranioplasty. The postoperative course was uneventful. Anatomopathological examination showed osteoblastoma with no sign of malignancy. This study and literature review highlight the clinical manifestation, the radiological and anatomopathological features as well as the management of osteoblastoma of the parietal bone of the cranial vault., Competing Interests: Les auteurs ne déclarent aucun conflit d´intérêts., (Copyright: Zoubida Bargach et al.)

Background: Osteoblastomas are rare primary bone tumors with a predilection for the spine. The extraosseous growth pattern is rare, and to our knowledge, only 2 cases of fully extraosseous osteoblastomas have been previously reported., Case Description: A man aged 36 years presented with a 7-month history of low back pain radiating to the gluteal area. On examination, a typical L5 radiculopathy was noted. The radiologic examinations conducted in the previous months pointed out the rapid growth of an extraosseous mass occluding the right L5-S1 foramen. Partial laminectomy was performed to achieve gross total resection. Histological analysis was consistent with osteoblastoma., Conclusions: Osteoblastomas with extraosseous extension are uncommon, and an exclusively extraosseous presentation is anecdotal. This can lead to preoperative misdiagnosis when typical radiologic characteristics of bone-forming tumors are missing. We describe the case of an extraosseous lumbar osteoblastoma whose clinical and radiologic presentation was suggestive of malignancy., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Osteoblastomas are a type of primary osseous neoplasm that exhibit a proclivity for the spine, primarily the posterior elements. While generally considered benign, some variants of osteoblastoma exhibit aggressive growth with lytic osseous destruction and soft tissue invasion, with some recurring after initial treatment. Given their proximity to vital structures and potential for rapid growth, these tumors are often managed with aggressive surgery, with en-bloc resection preferred., Methods: Here we describe our osteotomy technique for resecting en bloc a posterolateral thoracic osteoblastoma causing rapidly progressive myelopathy in a 17-year-old male., Results: Successful treatment of osteoblastoma in a 17-year-old male demonstrates the efficacy of our laminopedicular osteotomy technique in treating 1 instance of a rapidly presenting spinal tumor., Conclusions: This case bolsters the growing body of literature that favors the outcomes of a more conservative approach to en-bloc resection of spinal tumors., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Although osteoblastoma is an uncommon benign bone tumor, it sometimes behaves in a locally aggressive fashion. We herein report a case of recurrent lumbar spine osteoblastoma that was treated by repeated surgery and carbon ion radiotherapy., Case Presentation: A 13-year-old Japanese girl presented with left side lumbar pain. Computed tomography and magnetic resonance imaging of the lumbar spine demonstrated a tumorous lesion in the left side pedicle of L4. Although gross total resection of the mass, including the nidus, was performed in the initial surgery, recurrence was observed repeatedly in the short term and the pathological diagnosis of all of the resected tumors was conventional osteoblastoma. We finally performed carbon ion radiotherapy after the patient's 3rd palliative operation, and achieved a good outcome. No further recurrence has been observed in 10 years of follow-up., Conclusion: We performed carbon ion radiotherapy for a case of recurrent spinal osteoblastoma and achieved a good outcome without recurrence at 10 years after carbon ion radiotherapy treatment. To the best of our knowledge, this is the first case of osteoblastoma that was treated with carbon ion radiotherapy after multiple surgeries.

Background: Osteoblastoma is a rare benign aggressive tumor, with one third occurring in the spine. Conversion of osteoblastoma to osteosarcoma is uncommon, and histologically proven conversion has been rarely reported., Case Description: Cases of 2 patients with rare occurrences of spinal osteoblastomas recurring and transforming into osteosarcomas are presented. Initial presentation, treatment, imaging, and histology findings are described. The outcomes of the patients following surgical intervention for histologically diagnosed osteoblastoma with subsequent transformation to osteosarcoma and relative management are described. A literature review of osteoblastoma converting to osteosarcoma also is provided., Conclusions: The rare occurrence of osteoblastoma converting to osteosarcoma imparts several lessons, including performing Enneking appropriate surgery for benign aggressive tumors (Enneking stage 3) and always performing a biopsy, particularly at the time of recurrence if imaging is not pathognomonic for a benign primary spine tumor., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Osteoblastoma (OBL) in the mobile spine is a benign tumor with aggressive potential. There is not much published information on OBL of the mobile spine as a result of rarity of the disease. There are controversies over the aggressive subtype and prognostic factors of the condition., Objective: To explore the aggressive subtype and investigate prognostic factors of OBLs in the mobile spine., Methods: A retrospective analysis of spinal OBL was performed by survival analysis. Patients in 2 cohorts were analyzed based on the Enneking grade and pathological evaluation. Local recurrence-free survival (RFS) was estimated using the Kaplan-Meier method to identify potential prognostic factors. Factors with P ≤ .05 were subjected to multivariate analysis by Cox regression analysis. P ≤ .05 were considered statistically significant., Results: Included in this study were 70 patients with spinal OBL who were followed up by a mean of 67.1 mo (range 24-188). Local recurrence was detected in 9 cases after initial surgery, and death occurred in 2 cases. The result of statistical analysis suggested that Epithelioid OBL (EO) with Enneking stage 3 (St.3) and total spondylectomy were independent prognostic factors for RFS., Conclusion: St.3 or EO lesions seem to be more aggressive than St.2 or conventional osteoblastomas, but St.3 and EO should be considered simultaneously in predicting the aggressiveness of the lesion and the risk of recurrence. Total spondylectomy performed either by en bloc or piecemeal could significantly reduce recurrence of OBLs in the mobile spine., (Copyright © 2018 by the Congress of Neurological Surgeons.)

Purpose: To explore the typical magnetic resonance imaging (MRI) pattern of osteoblastoma (OB) after radiofrequency ablation (RFA) treatment and to identify signs indicating treatment success or relapse. Materials and methods: Forty-four follow-up MRI examinations of 15 patients with OB who had undergone 19 RFA procedures were analyzed retrospectively. An early follow-up group (1-4 months after RFA) and a late follow-up group (8-131 months after RFA) were established. The groups were further subdivided according to treatment success. Images were analyzed for the presence of central nidus enhancement (CNE), peripheral nidus enhancement (PNE), perifocal bone marrow edema (PBME) and fatty nidus conversion (FNC). Results: The early follow-up MRI image from every patient in the treatment success group exhibited a target-like appearance with negative CNE and positive PNE or PBME. PNE and PBME were observed in 93% and 71% of the early follow-up images, respectively. A target-like appearance was observed in 25% of the late follow-up images, and PNE and PBME were each observed in 20% of these images. FNC was not observed in the early follow-up images, but was seen in 55% of the late follow-up images. All three MRI images of the patients exhibiting clinical recurrence demonstrated strong CNE, PNE and extensive PMBE, which was in contrast to the images of the patients exhibiting treatment success. Conclusion: A target-like appearance of OB in early follow-up MRI examination indicates treatment success. PNE and PBME typically reduce over time and can lead to FNC in successfully treated patients. CNE recurrence, PNE and extensive PBME are signs of relapse.

Objectives: Spinal secondary aneurysmal bone cyst (SABC) is extremely rare with few published reports available at present. Our aim is to explore the clinicopathologic features, surgical modalities and outcomes of spinal SABC., Patients and Methods: A retrospective study of 33 patients with spinal SABC who were surgically treated in our center between 2010 and 2018 was performed. Clinical data, treatment options, complications and outcomes were analyzed., Results: Of the 33 patients, 12 were male and 21 were female, with a mean age of 32 years. Eleven lesions were located at the lumbar spine. The underlying lesions included giant cell tumor (GCT) (n = 20), osteoblastoma (n = 7), hemangiaoma (n = 3), fibrous dysplasia (n = 2) and osteosarcoma (n = 1). Preoperative selective arterial embolization was applied in 24 patients. All the patients were treated surgically through either subtotal resection (n = 1), piecemeal total resection (n = 21), or total en bloc resection (n = 11). Four patients experienced recurrence and one patient died during the follow-up period., Conclusion: Spinal SABC is popular in the third and fourth decade of life with female predominance. GCT is the most common underlying lesion. Preoperative arterial embolization is recommended, while surgery is the mainstay of treatment for spinal SABC. En bloc resection is recommended for spinal SABCs especially when underlying tumor is aggressive or malignant., (Copyright © 2019 Elsevier B.V. All rights reserved.)

OBJECTIVE. The aim of this observational study was to assess safety and clinical outcomes of percutaneous image-guided cryoablation (CA) to treat osteoblastomas (OBs) at various osseous sites. MATERIALS AND METHODS. A retrospective search was performed to identify patients presenting with painful OBs who underwent CA at the University Hospitals of Strasbourg between March 2007 and December 2018. Ten patients (seven men, three women; median age, 21 years old) were identified and included. Medical records were reviewed to assess complications and clinical outcomes. RESULTS. Median OB diameter was 16.5 mm (range, 16-28 mm). OBs were located in the spine ( n = 7), calcaneus ( n = 1), fibula ( n = 1), and third metacarpal bone ( n = 1). In 90% of cases ( n = 9), one or more critical structures were within 1 cm of the OB (median distance, 5 mm; range, 2-8 mm), thus requiring extensive protective measures. Technical success was achieved in all cases. Two (20%) immediate neural complications were noted. One major complication was consistent with a permanent sensory deficit of the arm. One minor complication was consistent with a transient right Horner syndrome, which completely resolved after 48 hours with high-dose steroids. Median clinical follow-up was 12 months. Primary clinical success was 100% and 78% at 1 and 12 months of follow-up, respectively, with two patients presenting with recurring pain. CONCLUSION. Percutaneous image-guided CA represents an effective therapeutic option for patients affected by painful OBs; the safety profile of the procedure is acceptable as long as comprehensive protective measures are deployed in light of the frequent close proximity of critical structures.

Osteoblastoma is a rare, benign primary tumor of bone, accounting for < 1% of all bone tumors. We report the case of a 27-year-old female who developed pain and swelling five and a half years after a clavicular fracture and was subsequently found to have an osteoblastoma arising at the fracture site. This is the first reported case of an osteoblastoma developing after a fracture, although osteoid osteomas, which are histologically indistinguishable from osteoblastomas, have been reported at prior fracture sites. This report demonstrates that secondary neoplasms such as osteoblastomas should be considered in the differential diagnosis for pain at a healed fracture site recurring years after the initial trauma.

A 7-year-old neutered male domestic shorthair cat was presented with chronic lameness in the right forelimb. A cystic bony lesion was identified in the distal right humerus and amputation was performed. The epiphyseal trabecular bones of the capitulum and trochlea was replaced by a tan to pink, expansile mass that was surrounded by a thin rim of cortical bone. Microscopically, the tumour was composed of a bland, osteoid producing spindle cell population within a well-vascularized fibrous stroma. Radiographical and histological features were consistent with osteoblastoma. Osteoblastoma and the related osteoid osteoma are uncommon, benign osteoblastic tumours that are reported rarely in animals. These tumours should be considered as differential diagnoses for slow growing, cystic bony lesions in cats., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: To evaluate technical success and long-term outcome of CT-guided radiofrequency ablation (RFA) of spinal osteoid osteomas (OO) and osteoblastomas (OB) in six different European centres., Methods: Eighty-seven patients with spinal OO (77) or OB (10) were treated with CT-guided RFA, after three-dimensional CT-guided access planning. Patient's long-term outcome was assessed by clinical examination and questionnaire-based evaluation including 10-point visual analogue scales (VAS) regarding the effect of RFA on severity of pain and limitations of daily activities. Clinical success was defined as a reduction of > 30% in the VAS score and patient's satisfaction., Results: Overall, RFA was technically successful in 82/87 cases (94.3%) with no major complications; clinical success was achieved in 78/87 cases (89.7%). The OO/OB were localized in the cervical (n = 9/3), the thoracic (n = 27/1), the lumbar (n = 29/4), and the sacral spine (n = 12/2). A decrease in severity of pain after RFA was observed in 86/87 patients (98.9%) with a persistent mean reduction of overall pain score from 8.04 ± 0.96 to 1.46 ± 1.95 (p < 0.001) after a median follow-up time of 29.35 ± 35.59 months. VAS scores significantly decreased for limitations of both daily (5.70 ± 2.73 to 0.67 ± 1.61, p < 0.001) and sports activities (6.40 ± 2.58 to 0.67 ± 1.61, p < 0.001)., Conclusion: In a multicentric setting, this trial proves RFA to be a safe and efficient method to treat spinal OO/OB and should be regarded as first-line therapy after interdisciplinary case discussion.

Background: Osteoblastomas (OTB) with co-existent aneurysmal bone cysts (ABC) of the spine are extremely rare and more so in the lumbar spine. To the authors' knowledge, only one case of lumbar spine involvement has been reported in a paediatric patient., Objectives: To highlight diagnostic challenges and surgical management of co-existent lumbar OTB-ACB in a child., Methods: We present a 14-year old female with low back pain and progressive swelling of 2 months. She was evaluated by neuroimaging studies and histopathological assessment of resected tissue., Results: X-ray showed a lytic lesion in L3 with loss of the left pedicle. Magnetic resonance imaging (MRI) revealed a fluid-filled, heterogeneously enhanced, lobulated lesion posterior to the vertebral bodies of L3, L4 and L5, which infiltrated the quadratus lumborum muscles bilaterally, and histologically diagnosed as ABC. The L3 pedicle also revealed an expanded, heterogeneously enhanced mass lesion which appeared to be different and showed no fluid-filled levels, histologically diagnosed as OTB. Surgical intervention involved tumour excision with partial spondylectomy of L3 vertebra, posterior instrumented stabilization and fusion., Conclusion: The case highlights the diagnostic challenges of co-existent OTB-ABC and the significant role of surgical management via spinal reconstruction, stabilization and fusion after gross total tumour excision., (© 2019 Ibebuike et al.)