Bone metastases from chondroblastoma: a rare pattern of metastatic disease in an adult.

Chondroblastoma is a rare benign tumor, typically presenting in the first two decades. Systemic metastases in chondroblastoma are extremely rare and it is the rarity of these metastases which lead the World Health Organisation to re-classify this lesion from "intermediate" to "benign" in its updated classification of bone tumors in 2020. We present an unusual case of a 55 year-old male patient who presented with multiple FDG-avid bone lesions on a background of conventional chondroblastoma of the rib excised at another institution 11-years previously. Two of these lesions were also histologically-proven as conventional chondroblastoma at biopsy. This case highlights that, although rare, metastases can be seen in patients with chondroblastoma. To our knowledge, this is the only case with an unusual pattern of metastases limited to bone.

Chondroblastomas in Children and Young Adults: Revision of 55 Cases.

BACKGROUND: Chondroblastomas are uncommon primary bone tumors localized in long bone epiphyses in children and young adults. The risk of metastasis is rare, but they have a high capacity for local recurrence. Surgical curettage with bone grafting or bone substitute is the preferred treatment. METHODS: We performed an observational retrospective study of chondroblastomas treated in 2 hospitals in Barcelona from 1988 to 2018. We reviewed the location of the tumor, clinical presentation, imaging, histopathology, initial treatment, and cases of recurrence with a review of their treatment. We assessed the correlation between recurrence and index surgery, anatomic location, and certain histopathologic findings (presence of mitotic figures, necrosis, and positivity for protein S-100). RESULTS: The series included 55 patients treated from 1988 to 2018, with ages ranging from 6 to 26, and a mean follow-up of 6.1 years (±3.7). The most common location was the distal femur metaphyseal/epiphyseal region. The most frequent clinical presentation was pain in the affected. Forty-five cases (81.8%) were treated with curettage of the tumor, and 4 cases (7.3%) with a wide resection. Forty-two cases (85.7%) received bone substitutes after curettage or resection. We found 5 cases of recurrence (9.1% recurrence rate); however, we could not find a statistically significant correlation between index surgery and recurrence ( P =0.24), anatomic location and recurrence ( P =0.49), or recurrence and histopathologic findings (mitotic figures, P =0.49; necrosis, P =0.60; positivity for protein S-100, P =0.52). In all the cases the treatment for the local recurrence was surgical, with a final healing rate of 100%. CONCLUSIONS: Chondroblastomas should be considered in children and adolescents when presenting with pain and an image suggestive of a tumoral lesion on plain x-ray, most frequently in epiphyses of long bones.Surgical treatment is preferred, obtaining good results after curettage and bone substitute. Chondroblastomas are tumors with a high capacity for recurrence, therefore an adequate surgical technique and surgeon experience are paramount to achieve good outcomes. LEVEL OF EVIDENCE: Level IV (case series). Therapeutic studies-investigating results or treatment.

Clinicopathological characteristics and prognostic factors in axial chondroblastomas: a retrospective analysis of 61 cases and comparison with extra-axial chondroblastomas.

BACKGROUND: A comprehensive understanding of the clinical characteristics and prognostic factors associated with axial chondroblastoma (ACB) is still lacking. This study aimed to understand the clinical characteristics and prognostic factors of axial chondroblastoma (ACB) and compare them with extra-axial chondroblastoma (EACB). METHODS: A retrospective review of our institution's local database was conducted, encompassing a total of 132 CB patients, of which 61 were diagnosed with ACB and 71 with EACB. Immunohistochemistry was employed to evaluate the expression levels of vimentin, S100, and cytokeratin. RESULTS: ACB and EACB shared similar characteristics, with the exception of advanced age, tumor size, elevated Vim expression, incidence of surrounding tissue invasion, and postoperative sensory or motor dysfunction. While wide resection and absence of surrounding tissue invasion consistently showed a favorable association with survival in both ACB and EACB cohorts during univariate analysis, most parameters exhibited differential prognostic significance between the two groups. Notably, the significant prognostic factors for local recurrence-free survival in the ACB cohort included the type of resection and the presence of chicken-wire calcification. In the multivariate analysis of overall survival, the type of resection emerged as a significant predictor in the ACB cohort, whereas in the EACB group, the type of resection and the occurrence of postoperative sensory or motor dysfunction were predictive of overall survival. CONCLUSION: There may exist distinct biological behaviors between ACB and EACB, thereby providing valuable insights into the prognostic characteristics of ACB patients and contributing to enhanced outcome prediction in this particular patient population.

Long term outcome of surgical treatment of chondroblastoma: analysis of local control and growth plate/articular cartilage related complications.

BACKGROUND: Chondroblastoma (CBL) is a rare benign chondroid producing bone tumor that typically occurs in epiphysis or apophysis of growing children and young adults. Intralesional curettage is the treatment of choice, while resection is required in selected cases, even though the use of minimally invasive ablation techniques has been advocated. Authors reviewed a series of 75 CBLs with the aim of assess risk factors for local recurrence, the growth plate related complications after epiphyseal curettage and the risk of arthritis of the adjacent joint after epiphyseal curettage. METHODS: We retrospectively review 69 CBLs treated with intralesional curettage and 6 treated with resection from March 1995 to February 2020. The median age was 18.8 years (7 to 42, median 16). The site was proximal humerus in 18 cases, proximal tibia in 17, distal femur in 16, talus in 6, femur's head in 4, calcaneus in 3, acromion in 3, trochanteric region in 2, distal tibia in 2, patella in 2, supracetabular region in 1 and distal humerus in 1 patient. RESULTS: Mean follow-up was 124.2 months (24 to 322, median 116). Among patients treated with curettage, 7.3% of local recurrence was observed and 12 (17.4%) patients developed osteoarthritis of the adjacent joint. Five patients (7.3%) presented limb length discrepancy of the operated limb ranging from 0.5 to 2 cm. Recurrence free survival rate was 94.2% at 5 and 91.6% at 10 years. A mean Musculoskeletal Tumor Society (MSTS) of 29.3 points (20 to 30, median 30) was observed. CONCLUSION: More than 90% of CBLs were successfully treated with aggressive curettage but segmental resection is required in selected cases. In a relatively small proportion of cases long term complications can occur due to growth plate damage or osteoarthritis. TRIAL REGISTRATION: Retrospectively registered.

A report of an intracortical chondroblastoma of the diaphysis in a skeletally mature patient.

Chondroblastomas characteristically occur in skeletally immature patients, and arise within the medullary canal of the epiphysis. We report a rare case of an intracortical chondroblastoma arising in the diaphysis, and occurring in an adult in his 3rd decade of life. Immunohistochemistry results were critical to confirmation of this rare diagnosis, with immunohistochemistry showing S100, DOG1, and H3K36me3 positivity in the neoplastic cells.

Direct femoral head approach without surgical dislocation for femoral head chondroblastoma: a report of two cases.

BACKGROUND: Chondroblastomas are rare, benign, locally aggressive lesions that appear in the epiphysis. Surgery for femoral head chondroblastoma (FHCB) is difficult. Conventional treatment with curettage via a drilled tunnel along the femoral neck can damage the growth plate and is associated with high local recurrence rates. The trapdoor procedure, which directly facilitates lesion access from the femoral head articular surface, can reduce local recurrence and avoid growth plate damage, although it requires surgical dislocation. Little is known about the long-term results of this direct articular surface approach, and there are no case reports on trapdoor procedures without dislocation. CASE PRESENTATION: We report two cases (patients aged 12 and 15 years) of FHCB presented with coxalgia treated using the trapdoor procedure without surgical dislocation. Both surgeries were performed with patients in the semi-lateral position. The hip joint was exposed via an anterior approach, and a capsulotomy was performed at the superior rim of the acetabulum, followed by the external rotation of the hip joint. With a fine osteotome, a rectangular flap (trapdoor) was opened on the cartilage surface in the lateral non-weight-bearing area, and curettage of the lesion followed by bone and/or bone substitute grafting was performed. Subsequently, the trapdoor was replaced in its original position. There has been no local recurrence or femoral head aseptic necrosis after more than 6 and 12 years for patients 1 and 2, respectively. Both patients had musculoskeletal tumor society scores of 100% at follow-up and are enjoying a normal active life. CONCLUSIONS: This direct femoral head approach without dislocation may be a simple treatment alternative for FHCB.

Infratemporal Fossa Chondroblastoma.

INTRODUCTION: Chondroblastoma is a rare, benign mesenchymal tumor that can behave local aggressive. It most often occurs in the area of the epiphyses of long tubular bones, whereas the appearance in the region of the head and neck is rare, only few reports were published in literature. The incidence of chondroblastoma of the craniofacial region is about 6.4%. CLINICAL REPORT: A 46-year-old patient was hospitalized due to growth and pain in the area of the left half of the face, and a tumor of the left infratemporal fossa was diagnosed by computed tomography. The patient was operated with a preauricular surgical approach, parotidectomy, and complete tumor removal was performed. Pathohistological examination revealed chondroblastoma. CONCLUSIONS: Chondroblastoma of the craniofacial region is very rare pathohistological finding, characterized by slow and asymptomatic growth until it reaches the appropriate dimensions, the clinical symptomatology depends on the localization of the tumor. Computed tomography diagnostics provides important information about the location, size of the tumor, invasion of surrounding structures, and significantly contributes to the decision on the appropriate surgical approach. Diagnostic dilemma solving only final pathohistological verification.

Analysis for clinical feature and outcome of chondroblastoma after surgical treatment: A single center experience of 92 cases.

BACKGROUND: Chondroblastoma is a rare, benign, cartilaginous bone tumor derived from epiphyseal chondrocytes. Although the clinical characteristics and experience of surgical treatment of the smaller number of patients has been reported in the literature, it is difficult to draw conclusions about the clinical and radiographic features and the outcome for surgical treatment of this disease due to the rarity of chondroblastoma. This study was aiming to review the epidemiologic characteristics and outcome of surgical management for patients with chondroblastoma. METHODS: We performed a retrospective analysis of 92 patients with chondroblastoma. Clinical data, radiographic images, surgical treatment and outcome were analyzed. Eighty-two patients received the extensive intralesional curettage and ten cases had the En-block resection. RESULTS: The most common site of disease was proximal femur (20.7%, 19/92), followed by distal femur (18.5%, 17/92) and proximal tibia (16.3%, 15/92). The secondary aneurysmal bone cyst component was most common for chondroblastoma of the small irregular bones, such as patella and foot. Four (4.3%, 4/92) cases receiving the extensive intralesional curettage developed the local recurrence, respectively two at the proximal tibia, one at the pelvis and one at the calcaneus. Time to local recurrence were respectively 14.5, 8.8, 27.0 and 5.6 months, with the average 14 months. Kaplan-Meier estimated survivorship curve of local recurrence-free survival rates of one, two and five years were respectively 97.7%, 96.2% and 93.9%. The mean Musculoskeletal Tumor Society (MSTS) score was 29.4. At the last follow-up, no one had the pulmonary metastasis and death associated with the disease. CONCLUSION: Intralesional curettage plus local adjuvants can obtain satisfactory outcome for chondroblastoma. LEVEL OF EVIDENCE: Level IV.

Surgical hip dislocation for treatment of femoral head chondroblastoma: efficacy and safety.

PURPOSE: Femoral head chondroblastoma poses a surgical challenge. Anatomical limitations may lead to increased risk of local recurrence, damage to the articular cartilage, growth disturbances, and/or avascular necrosis (AVN). We are presenting our results with surgical hip dislocation approach with the aim to evaluate its efficacy in preventing recurrence and its safety, preserving a functional hip joint and avoiding complications. PATIENTS AND METHODS: Ten patients were managed using surgical hip dislocation with direct access to femoral head lesions, extended curettage through a modified trapdoor approach, and cement reconstruction. These were six males and four females, with a mean age of 17 ± 2.7 years (range: 14-20) and a mean follow-up of 34 ± 12 months (range: 17-57). The lesion extended into the neck in 60% of patients with the physis being either closed in seven or closing in three patients. RESULTS: We had a single case (10%) of recurrence at the trochanters for which re-curettage was done. However, all patients had their hips preserved with good function at the latest follow-up, and no serious complications recorded. The Musculoskeletal Tumor Society score improved significantly from a pre-operative median of 23.5 (range: 16-28) to a post-operative median of 29 (range: 26-30) (P = 0.005). CONCLUSION: This report describes a safe reproducible approach to effectively manage these locally aggressive lesions with good short-term results. This is done while maintaining the integrity of the articular surface, growth plate, as well as preserving the femoral head blood supply.

Percutaneous Radiofrequency Ablation of Appendicular Skeleton Chondroblastoma-an Experience from a Tertiary Care Cancer Center.

PURPOSE: To evaluate safety and long-term efficacy of radiofrequency (RF) ablation in treatment of chondroblastoma. MATERIALS AND METHODS: This retrospective analysis comprised 27 consecutive patients with histopathologically proven chondroblastoma treated by RF ablation. The tumors were located in the proximal humerus (n = 6), proximal tibia (n = 8), proximal femur (n = 6), distal femur (n = 5), acromion process (n = 1), and lunate (n = 1). In 19 patients (70.3%), the tumor was in the weight-bearing area of the bone. Clinical response was assessed by comparing pain scores and functional assessment by Musculoskeletal Tumor Society (MSTS) score before and after ablation. Patients were followed for a minimum of 1 year to rule out complications and recurrence. RESULTS: Technical success rate was 100%. Mean pain score before the procedure was 7.34 (range, 7-9); all patients experienced a reduction in pain, with 25 (92.6%) patients reporting complete pain relief at 6 weeks. Mean MSTS score before the procedure was 15.4, whereas mean MSTS score at 6 weeks after the procedure was 28.6, suggesting significant functional improvement (P < .0001). Two patients developed osteonecrosis and collapse of the treated bone. There were no recurrences. CONCLUSIONS: Percutaneous RF ablation is a safe and effective option for treating chondroblastoma of the appendicular skeleton.

Letter to the Editor concerning the article "Clinical outcomes of chondroblastoma treated using synthetic bone substitute: risk factors for developing radiographic joint degeneration".

The purpose of this letter to the Editor is to report some shortcomings in the statistical analysis and variable grouping in the recent publication of the article "Clinical outcomes of chondroblastoma treated using synthetic bone substitute: risk factors for developing radiographic joint degeneration," and to further explore some of the factors that may affect the clinical prognosis of chondroblastoma patients. We also suggest future prospective controlled studies with large samples to improve the limitations encountered by Outani et al. (World J Surg Oncol. 18(1):47, 2020) due to insufficient statistical power of variables and lack of controls.

Chondroblastoma of the patella with secondary aneurysmal bone cyst, an easily misdiagnosed bone tumor:a case report with literature review.

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.

Functional treatment of temporal bone chondroblastoma: retrospective analysis of 3 cases.

PURPOSE: To describe and analyse functional treatment of temporal bone chondroblastoma (TBCh). METHODS: From January 2000 to June 2019, at the Department of Otorhinolaryngology, Hôpital Lariboisière, Paris, France, patients with TBCh were enrolled in this study. All cases routinely performed pre-operatory work-up including evaluation of performance status, audio-vestibular function test, ear endoscopy, contrasted CT scan and MRI of head and neck region; in one case we also performed an angio-CT scan. All patients underwent resection of the tumour with a "functional" approach RESULTS: Three male patients (mean age 46,6 years)-two primary tumours and one recurrence-were treated. In all three cases the tumour invaded the middle ear with a variable degree of hearing loss and infiltration of temporal bone structures. All surgeries were performed with a microscopic approach associated with open/endoscopic approach when necessary. Inner ear and facial nerve were speared in all cases and the TMJ was partially resected in 2 cases due to its moderate involvement. At present, after a mean follow-up of 103 months (range 40-225 months), only one case presented recurrence which has been successfully treated with radiotherapy. CONCLUSIONS: Our results of treatment suggest that functional surgery can be relevant in the management of TBCh since it is focused on both treatment of this pathology and maintenance of a good quality of life.

Surgical Strategy of Pediatric Benign Sacral Tumors.

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.

[Conventional epiphyseal chondrosarcoma of childhood and adolescence: a case report]. / Konventionelles epiphysäres Chondrosarkom des Kindes- und Jugendalters: ein Fallbericht.

INTRODUCTION: Conventional chondrosarcoma is the second most common primary malignant bone tumor and usually occurs at older adult ages. It is rare in childhood and adolescence. CASE HISTORY: This case report presents the treatment course of a 13-year-old boy with a symptomatic chondrogenic tumor of the right distal femur. Histopathologically, an epiphyseal intermediate-grade chondrosarcoma (G2) was diagnosed. DISCUSSION: Based on the following case, potential radiological and histopathological differential diagnoses, such as chondroblastoma or chondroblastic osteosarcoma, are discussed against the background of current standards in orthopedic oncology.

Nomograms for predicting overall survival and cancer-specific survival of chondroblastic osteosarcoma patients.

BACKGROUND: The establishment of precise and personalized prediction systems for chondroblastic osteosarcoma patients is important for guiding the treatment. METHODS: The univariate logrank test and multivariate Cox regression analysis were performed to identify independent prognostic factors for overall survival (OS) and cancer-specific survival (CSS). Nomograms were constructed to estimate the OS and CSS based on these factors. Internal and external validation was performed. The predictive power of the nomograms was determined by C-index and calibration plots. RESULTS: A total of 401 chondroblastic osteosarcoma cases were identified. Univariate and multivariate analysis revealed that age at diagnosis, histological grade, tumor size, Surveillance, Epidemiology, and End Results stage, and surgical resection were independent prognostic factors for OS and CSS. The five factors were incorporated to construct the nomograms for estimating the 3- and 5-year OS and CSS. The C-index values for the internal validation of the OS and CSS nomogram were 0.732 and 0.746, respectively, and for the external validation were 0.780 and 0.808, respectively. The calibration curves revealed that the predicted OS and CSS could well match the actual survival rate. CONCLUSIONS: The nomograms for predicting 3- and 5-year OS and CSS were constructed and were proved to be accurate and reliable by the internal and external validation.

Clinical outcomes of chondroblastoma treated using synthetic bone substitute: risk factors for developing radiographic joint degeneration.

BACKGROUND: Chondroblastoma (CB) is a rare locally aggressive bone tumor that commonly occurs in the epiphysis or apophysis of long bones. Although surgical treatment of CB carries potential risk for physeal or articular cartilage damage, risk factors for joint degeneration have not been well described. In addition, we have mainly used synthetic bone substitute (SBS) to fill the bone defect after intralesional curettage as treatment for CB. This study thus aimed to evaluate the incidence of and risk factors for adjacent-joint radiographic degeneration after SBS treatment for CB. METHODS: We retrospectively reviewed 48 patients treated for CB at our institutions between 1996 and 2017. Clinical data, radiographic images, treatments, and local recurrence were analyzed. RESULTS: We identified 40 patients [29 males and 11 females with a mean age of 19 years (range, 8-35 years)] who received SBS to fill the defect after curettage with a minimum follow-up of 1 year. The mean follow-up period was 71 months (range, 13-239 months). A total of 8 patients (20%) developed local recurrence. Radiographic analysis showed that 5 patients (16.7%) developed radiographic joint degeneration. Joint degeneration was significantly associated with the affected joint (p = 0.004). CONCLUSIONS: Curettage and SBS filling had been found to be a reasonable treatment method for CB, which commonly occurs in the epiphysis or apophysis. Radiographic joint degeneration was not uncommon after CB treatment, especially in the talus and proximal humerus.

Management of cranial chondroblastoma in adults; a pooled analysis.

OBJECTIVES: Chondroblastoma is a rare bone tumour that often affects children more than adults. The adult cranial affection is a unique presentation of the disease (less than 2%) that mandates specific management. Through this pooled-analysis, we aimed to examine this disease group and obtain reliable scientific conclusions. METHODS: The literature was searched for case-reports of cranial chondroblastoma. Afterwards, a pooled analysis was done for the selected articles. The data in question were the patient's age, gender, disease site, modalities of treatment, disease control, salvage treatment, and disease-specific survival. RESULTS: 122 case reports were retrieved from the literature. The median age at diagnosis was 38.5 years. Up to the moment, the standard of care remains complete resection. The relapse-free survival was 29.5 months, with a three-year relapse rate of 9% and disease-specific mortality of 0%. Most of the relapses were salvaged excellently with excision. The strongest predictor for relapse was the post-resection residual disease, with three-years relapse rates of 23.8% and 2.4% for positive and negative residuals, respectively. Adjuvant Radiotherapy failed to improve the relapse rates. CONCLUSION: Complete surgical excision is the standard of care. Post-surgical residual is the only adverse prognostic factor that predicts poor disease control.

Pediatric Chondroblastoma and the Need for Lung Staging at Presentation.

PURPOSE: Chondroblastoma is a benign, but potentially locally aggressive, bone tumor with predilection for the epiphysis of long bones in growing children. Historically, there is a reported 2% risk of lung metastasis, however these cases are mostly in the form of isolated single reports and the vast majority in adults. The purpose of this study was to identify the "true" risk of lung metastases at presentation in skeletally immature patients with a benign chondroblastoma, and therefore revisit the need for routine chest staging. METHODS: This was a multi-institution, international retrospective study of children and adolescents diagnosed and treated for a benign chondroblastoma. We focused on the screening and diagnosis of lung metastasis, type of staging utilized and the incidence of local recurrence. Detailed review of the available literature was also performed for comparison. RESULTS: The final studied cohort included 130 children with an average age of 14.5 years (range: 6 to 18 y). There were 94 boys and 36 girls. Lesions more often involved the proximal humerus (32/130), proximal tibia (30/130), and proximal femur (28/130). At an average follow-up of 50 months, there were 15 local recurrences (11% rate) and no cases of lung metastasis. All patients underwent chest imaging at presentation. The overall reported lung metastases rate in the pulled literature review (larger series only) was 0.4% (7/1625), all patients were skeletally mature. CONCLUSIONS: This is the largest cohort of pediatric-exclusive chondroblastoma in the literature. Despite minor differences in management between the centers included, the recurrence rate was similar and there was no evidence of lung metastasis (0 in 130). The incidence of distant involvement in a true benign chondroblastoma in children is much lower than the 2% previously reported in the literature, and the need for routine chest staging should be revisited. LEVEL OF EVIDENCE: Level III.

[Treatment of chondroblastoma of the humeral head : A tumour- and shoulder-orthopaedic challenge]. / Die Behandlung des Chondroblastoms im Humeruskopf : Eine tumor- und schulterorthopädische Herausforderung.

We present the case of a 22-year-old female patient with chondroblastoma in the right humeral head. To allow a gentle and anatomic resurfacing of the humeral joint surface and to avoid total joint arthroplasty in our young patient with high functional requirements, we implanted a HemiCAP® after intralesional curettage of the chondroblastoma. Our patient's excellent short-term functional outcome shows that our approach can be considered a very good therapeutic option.