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.

Periosteal chondroblastoma of the femoral neck: two cases and a review of the literature

Chondroblastoma is a rare benign cartilaginous tumor mostly confined to the epiphyses and apophyses. Cases outside the epiphyseal region are exceedingly rare. Extramedullary chondroblastomas are exceptional; to our knowledge, only two cases qualified as "periosteal chondroblastoma" have been described in the literature. We report two cases of metaphyseal periosteal chondroblastoma both located on the inferior surface of the femoral neck. Both cases were paucicellular with an unusual dense sclerotic reaction. The diagnosis of chondroblastoma was supported by the expression of histone 3.3, K36M mutant in tumor cells.

A rare presentation of recurrent chondroblastoma of scapula, acromion and lateral end of clavicle

About 1% of primary bone tumours are chondroblastoma, which develop from secondary ossification centers of long bones, preferably. The scapula, clavicle, and acromion are the rarest sites for this tumour. The recurrence rate is 14-18%, depending on the site of origin. There are various treatment options, but extended curettage and bone grafting are the main treatment modalities for chondroblastoma. In cases of recurrence, marginal excision and wide local excision are the treatments used. Here we report a recurrent tumour in that location that was removed by wide local excision. After 2 years of follow-up, there were no signs or symptoms of recurrence noted. This case is notable for its rare site of occurrence and successful surgical management without any episodes of re-occurrence after a 2-year follow-up period.

Utility of immunohistochemical expression of H3.3K36M and DOG1 in the diagnosis of chondroblastomas: An experience from a tertiary cancer referral center

Despite its characteristic clinicopathological features, chondroblastoma may pose a diagnostic challenge, given its morphological spectrum, potential for subdiagnostic appearances in limited biopsy specimens, and its potential mimicry of other entities. Recently, a characteristic H3F3B mutation underlying most chondroblastomas was described, which led to the identification of H3.3K36M as the corresponding diagnostic immunohistochemical marker. The present study is an evaluation of immunohistochemical features of 26 chondroblastomas, including DOG1 and H3.3K36M immunostaining. H3.3K36M immunostaining was graded as 1+, 2+ and 3+ in terms of staining intensity. There were 17 males and 9 females (M:F = 1.8:1) with ages ranging from 7 to 34 years (average = 16.7, median = 16). The most common location was proximal humerus (8, 30.7 %) followed by proximal tibia (5, 19.2 %), distal femur (3, 11.5 %), proximal femur (3, 11.5 %), pelvis (2,), followed by distal tibia, calcaneum, upper sternum, scapula, and D9 vertebra, in a single case, respectively. Eighteen (69.23 %) tumors displayed all the classic histopathological features. Immunohistochemically, the tumor cells were positive for S-100 P (19/22, 86.3 %), DOG1 (focal to patchy) (21/23 91.3 %), and H3.3K36M (26/26, 100 %). H3.3K36M tested in other tumors, constituting diagnostic mimics of a chondroblastoma, such as giant cell tumor of bone, chondromyxoid fibroma, and tenosynovial giant cell tumors, showed negative staining. Six tumors, initially diagnosed as chondroblastomas were reclassified into other entities with the help of negative H3.3K36M immunostaining. The present study reinforces H3.3K36M as a highly sensitive and specific marker for diagnosing chondroblastoma, including small biopsies, and in uncommon tumor sites with variable histopathological features. DOG1 is also useful in reinforcing a diagnosis of chondroblastoma in a clinicoradiological context, especially in laboratories lacking H3.3K36M immunostain. However, its staining pattern is variable.

Recurrent chondroblastoma of the acetabulum in an adult

Chondroblastoma is a rare, benign neoplasm of chondroblast cell origin, accounting for less than 1% of primary bone tumors. It is usually diagnosed in the second decade of life with most of the cases involving the long bones such as the femur and humerus. Furthermore, over 90% of cases are in individuals under 30 years of age. In older adults, chondroblastomas are typically found in bones in the foot, such as the talus and calcaneus. Treatment is usually local curettage of the lesion with a relatively low rate of recurrence. In this case report, we present a patient with an atypical age of initial presentation at 49 years, a rare location of the chondroblastoma in the acetabulum, and a recurrence 14 years after surgical resection in the same location. The lesion's radiographic findings of intralesional calcifications alongside the high-signal, heterogeneous composition on T2-weighted MRI were supportive of the atypical diagnosis of chondroblastoma in this patient.

A rare case of chondroblastoma involving the distal phalanx of the ring finger

Chondroblastoma, a rare benign bone tumor, is typically found in the epiphysis of long bones, with hand involvement being particularly uncommon. We present a case of an 11-year-old female with chondroblastoma involving the fourth distal phalanx of the hand. Imaging revealed a lytic, expansile lesion with sclerotic margins and no soft tissue component. A preoperative differential diagnosis included intraosseous glomus tumor, epidermal inclusion cyst, enchondroma, and chronic infection. The patient underwent open surgical biopsy and curettage for both diagnostic and treatment purpose. The final histopathologic diagnosis was chondroblastoma.

Recurrent chondroblastoma of the talus: A case report and literature review of recurrent lesions in the foot and ankle

INTRODUCTION AND IMPORTANCE

Chondroblastoma is a benign cartilaginous tumour that usually presents in the epiphysis of long bones in patients aged 10-20 years old. Only 4 % of primary chondroblastoma occur in the talus. Recurrence is rare, especially in the foot and ankle and there is no consensus regarding how it is best managed. This unique case and literature review add to a limited evidence base.

CASE PRESENTATION

A 21-year-old male was referred to our elective orthopaedic clinic with persistent anterior ankle pain exacerbated by weight-bearing. Radiographs and MRI revealed a 2.5 cm non-homogenous mass in the anteromedial talus with expansion of overlying bone consistent with chondroblastoma-ABC. Our patient was initially managed by intralesional curettage and autologous bone grafting but had recurrence 4.5 months postoperatively. Subsequent en bloc resection of the talar neck with talonavicular and calcaneocuboid joint fusion resulted in excellent functional outcomes and disease-free survival at 2 years follow-up.

CLINICAL DISCUSSION

There are few reports discussing treatment options for recurrence in the foot and ankle. Successful treatment of primary and recurrent lesions depends on complete local resection. Repeat curettage or en bloc resection are effective options depending on tumour size and location. Type of bone graft or void filler should be considered on a case-by-case basis. Novel therapies (e.g. phenol instillation) may be beneficial.

CONCLUSION

This case details successful management of recurrent chondroblastoma with en bloc resection of the talar neck and hindfoot reconstruction. We review the efficacy and outcomes of all previously reported recurrent chondroblastoma in the foot and ankle. We highlight multiple potential treatment options.

Chondroblastoma of foot bones; a clinicopathological study of 29 cases confirming the diagnostic utility of H3K36M and H3G34W antibodies at an uncommon site

OBJECTIVE

Chondroblastoma (CB) is a benign cartilaginous bone neoplasm which commonly occurs in long bones of adolescents. CB can uncommonly involve foot. Its mimics include both benign and malignant lesions. H3K36M immunohistochemical (IHC) stain is a helpful tool for establishing the diagnosis of CB in such challenging situations. In addition, H3G34W IHC stain helps to rule out giant cell tumor which is the closest differential of CB. Our objective was to describe the clinicopathological features and frequencies of H3K36M, H3G34W and SATB2 IHC stains in CB of foot.

MATERIALS AND METHODS

We reviewed H&E slides and blocks of 29 cases diagnosed as "chondroblastoma" of foot at our institutions.

RESULTS

Patient's age ranged from 6 to 69 (mean: 23.3 and median: 23) years. Males were almost 5 times more commonly affected than females. Talus and calcaneum were involved in 13 (44.8 %) cases each. Microscopically, tumors were composed of polygonal mononuclear cells and multinucleated giant cells and chondroid matrix. Other histological features included aneurysmal bone cyst-like (ABC-like) change (44.8 %), osteoid matrix (31 %), chicken-wire calcification (20.7 %), and necrosis (10.3 %). H3K36M was expressed in 100 % and SATB2 in 91.7 % cases. H3G34W was negative in all cases, where performed. One out of 11 patients with follow up information developed local recurrence after 48 months.

CONCLUSION

CB in foot occur at an elder age and show more frequent ABC-like changes as compared to long bones. Males are affected ~5:1 as compared to 2:1 in long bones. H3K36M are H3G34W are extremely useful diagnostic markers for CB, especially elderly (aged or higher) patients and we report the largest series of foot CB cases confirmed by immunohistochemistry.

Lys36Met Mutation

Background: Chondroblastoma is a primary bone tumor typically arising from the intramedullary space of the epiphysis or epimetaphysis. A non-epiphyseal chondroblastoma is uncommon. Case report: An 11-year-old girl presented with an eccentric cortical osteolytic lesion in the distal femur metaphysis. The typical morphology, diffuse H3.3 K36M immunohistochemical expression and H3F3B point mutation (c. 110A > T) unequivocally supported the diagnosis of chondroblastoma. Discussion: We described a non-epiphyseal cortical-based chondroblastoma involving the distal femur harboring the typical H3F3B mutation. Non-epiphyseal chondroblastoma may harbor the H3F3B mutation.

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.

Metaphyseal chondroblastoma in a pediatric patient

Chondroblastoma is a rare, benign neoplasm usually located in the epiphyses and apophyses of the long bones in the immature skeleton. Radiologically, these tumors have a classic appearance of a lytic lesion with chondroid matrix surrounded by a thin sclerotic rim. Here, we describe the case of a 5-year-old male who presented with a chondroblastoma unusually located exclusively in the metaphyseal region, which led to an elusive diagnosis. The presence of tumors outlying the traditional location or epidemiological spectrum, along with the potential for histopathological misdiagnosis, can pose a diagnostic and therapeutic challenge for the treating team.

Expression of SATB2, RUNX2, and SOX9 and possible osteoblastic and chondroblastic differentiation in chondroblastoma

Chondroblastoma (CB) is histologically characterized by oval to polygonal-shaped mononuclear neoplastic cells, multinucleated osteoclastic giant cells, and eosinophilic matrix with occasional calcification. Genetically, the majority of CBs harbor H3F3B p.K36M mutation. Despite the historical nomenclature, it has been reported that the matrix of CB is similar to osteoid rather than true cartilage; however, it remains unclear whether neoplastic cells in CB have the potential for osteoblastic differentiation. To clarify this issue, we immunohistochemically examined the expression of osteogenic and chondrogenic markers (SATB2, RUNX2, p63, and SOX9) as well as H3K36M mutant protein in 33 cases of CB. All 33 cases of CB were positive for H3K36M, while SATB2, RUNX2, p63, and SOX9 were expressed in 30/33 (91%), 33/33 (100%), 29/33 (88%), and 31/32 (97%) CB cases, respectively. Our immunohistochemical results suggest that neoplastic cells in CB frequently express both osteogenic and chondrogenic markers and may have an intermediate feature of osteoblastic and chondroblastic nature.

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 3^rd 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.

Arthroscopic management of Juxta-articular chondroblastoma with bone substitutes - A case report

Chondroblastoma, a rare benign bone tumour arising from the epiphysis, accounts for approximately 1% of all primary bone tumours and is known to be locally aggressive with potential for metastases and local recurrence. Open surgical curettage is associated with high risk of recurrence and potential for damage to the physis resulting in growth disturbances. We report a 14-year-old girl with chondroblastoma involving the distal femoral epiphysis in whom an arthroscopic approach was employed for thorough curettage of the lesion under direct vision followed by cavity management using bone graft substitute. At seven years follow-up she is asymptomatic, has normal knee function and her radiographs have shown good osteointegration of the synthetic graft with no evidence of recurrence. By combining the principles of intra-articular and endosteal arthroscopy in select patients, both tumour excision and cavity management can be done arthroscopically.

Chondroblastoma of the knee in a teenager

Chondroblastoma is an uncommon osseous neoplasm that accounts for less than 1% of all bone tumors. Characteristically it arises in the epiphysis or apophysis of long bones in young patients and may extend into the metaphysis. A sixteen-year-old male presents with a 1-year history of left knee pain associated with joint stiffness and interfering with performing daily activities. Radiographic and contrast enhanced magnetic resonance imaging favored the diagnosis of chondroblastoma. This was then confirmed histologically. The clinical signs and symptoms of Chondroblastoma are usually nonspecific, pain is most often moderate and can be revealed as a result of a trauma. The definitive diagnosis is mainly pathological due to the lack of specificity of radiological findings consistent with the presented case.

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.

Benign Cartilage-forming Tumors

Although uncommon in many pathology practices, cartilage-forming tumors represent some of the most frequent primary bone tumors. Diagnosis can be challenging given their variable histologic spectrum and the presence of overlapping morphologic, immunohistochemical, and genetic features between benign and malignant entities, particularly low-grade malignancies. Correlation with clinical findings and radiographic features is crucial for achieving an accurate diagnosis and appropriate clinical management, ranging from observation to excision. Tumors can be characterized broadly by their location in relation to the bone (surface or intramedullary). In specific instances, ancillary testing may help.

Chondroblastoma in the Children Treated with Intralesional Curettage and Bone Grafting: Outcomes and Risk Factors for Local Recurrence

OBJECTIVE

To review the outcomes of surgical management in the pediatric patients with extremity chondroblastoma. Especially the risk factors of recurrence and growth disorder. And discuss a potential method to decrease the rate of growth disorder by preventing the premature physeal closure.

METHODS

Fifteen girls and twenty-seven boys aged from two to 14 years (mean, 11 years) with histologically proven chondroblastoma, who presented from January 2011 to June 2018 at our Hospital, were retrospectively reviewed. Clinical data, radiographic images, histological findings, treatment, functional outcomes, and local recurrence rate were analyzed. Surgical treatment included complete curettage of the tumor and the walls of the lesion followed by bone grafting, No adjuvant methods were used. Recurrence was defined as a return of symptoms and an expansion radiolucency at the operated site. It was confirmed by the histopathological analysis. When recurrence was diagnosed, the medical data were analyzed to detect the effect of different factors on local recurrence. Functional outcome was measured according to Sailhan's functional criteria, designed to provide a standardized method of assessing pediatric chondroblastoma patient postoperatively.

RESULTS

The proximal part of the femur was the most frequently involved site. All the patients had at least 24 months of follow-up; mean duration was 30 months (range, 24-60 months). The local recurrence rate was 9.5%. Three resolved after repeat surgeries without further recurrence, one had a second recurrence and received another more aggressive curettage. Local recurrence of chondroblastoma was associated with age (P < 0.05), while not associated with sex, tumor location, the radiological character of the lesion or the grafting method (P > 0.05). No pulmonary metastasis was noted at latest follow-up. Five patients suffered from premature closure of physis due to physis injury. Thirty-one patients (73.8%) had a good outcome, and all returned to normal unrestricted activities. Six patients (14.3%) had a fair outcome due to occasional pain, asymmetric range of motion, or radiographic joint changes without arthritis. And five patients (11.9%) had a poor outcome because of chronic pain, loss of joint motion impairing normal life activities, or a limb-length discrepancy and limp.

CONCLUSIONS

Aggressive curettage and bone grafting resulted in local control and good outcomes in most pediatric patients. Being less than 12 years of age was the risk factor for recurrence. For those growing patients, premature physeal closure was observed after the curettage, interpositional technique with PMMA would be a good choice for prevention.

Chondroblastoma treatment by radiofrequency thermal ablation: Initial experience and implementation

PURPOSE

To present our experience on the implementation of radiofrequency thermal ablation (RFA) for the treatment of chondroblastoma.

MATERIALS AND METHODS

This case series includes 12 patients (10 males) with chondroblastoma using RFA under CT guidance. Tumours were located in the humeral head (3), femoral head (2), distal femoral epiphysis (4), tibial epiphysis (2) and calcaneus (1). Tumour size ranged from 12 to 60 mm (median: 33 mm). According to tumour size and location, monopolar electrode's active tip ranged from 1 to 3 cm. Dry and perfused ablation mode was used to treat smaller (6) and larger (6) lesions, respectively. Cementation was also made in 5 cases. Technical success was considered if the tumour was treated according to the protocol and complete ablation was achieved. Clinical success was assessed according to a visual analogue scale.

RESULTS

Technical success was achieved in 11 of 13 cases (83%) afters the first treatment. After a second treatment in the 2 failed cases, pain control was achieved in all cases eventually (100% of clinical success). Follow-up MRI demonstrated resolution of oedema in all cases, as well as a necrotic area extending beyond the outer edge of the lesion in all cases except one. Radiography or CT showed stability of the lesions, with increased sclerosis and no cortex collapse. In one case, a 4 cm shortening of the humerus was observed at the end of skeletal development (7 years after treatment). In another case, early hip osteoarthritis was developed (15 years after treatment). No other long-term complications were observed.

CONCLUSION

Successful treatment of chondroblastoma can be achieved by RFA. Cementoplasty adds strength to the ablated bone in weight bearing areas. MRI hallmarks associated with clinical success were resolution of bone marrow edema, and area of necrosis extending beyond the tumour edge. Radiography and CT proved to be useful in demonstrating cortex integrity.

Percutaneous cryoablation of chondroblastoma and osteoblastoma in pediatric patients

BACKGROUND

To review the safety and efficacy of percutaneous cryoablation for the treatment of chondroblastoma and osteoblastoma in the pediatric and adolescent population.

MATERIALS AND METHODS

A retrospective review from 2016 to 2020 was performed to evaluate clinical and imaging response to percutaneous cryoablation in 11 symptomatic patients with diagnosis of chondroblastoma and osteoblastoma treated from two pediatric hospitals with at least 12-month follow-up. Technical success (correct needle placement and potential full coverage of the tumor with the planned ablation zone) and clinical success (relief of the symptoms) were evaluated. The primary objective was to alleviate pain related to the lesion(s). Immediate and late complications were recorded. Patients were followed in clinic and with imaging studies such as MRI or CT for a minimum of 6 months.

RESULTS

A total of 11 patients were included (mean 14 years, age range 9-17; male n = 8). Diagnoses were osteoblastoma (n = 4) and chondroblastoma (n = 7). Locations were proximal humerus (n = 1), femur condyle (n = 1), and proximal femur (n = 1) tibia (n = 3), acetabulum (n = 3), thoracic vertebra (n = 1) and lumbar vertebra (n = 1). Cryoablation was technically successful in all patients. Clinical success (cessation of pain) was achieved in all patients. No signs of recurrence were observed on imaging follow-up in any of the patients. One of the patients developed periprocedural right L2-L3 transient radiculopathy as major immediate complication.

CONCLUSIONS

Percutaneous image-guided cryoablation can be considered potentially safe and effective treatment for chondroblastoma and osteoblastoma in children and adolescents.

Sacral chondroblastoma — a rare location, a rare pathology: A case report and review of literature

BACKGROUND

Chondroblastoma (CB) is an intermediate tumor of cartilage origin. CB involving the sacrum is a very rare pathology.

CASE SUMMARY

A 17-year-old male with sacral CB was diagnosed as CB during the first surgery, and 18 mo later, the tumor recurred and a second surgery was performed with the same pathology result of CB.

CONCLUSION

We recommend complete removal of the tumor in a timely manner, provided that surgical conditions are met. At the same time, other diseases should be carefully differentiated in terms of imaging or pathological features so as to avoid erroneous diagnostic conclusions.

A large invasive chondroblastoma on the temporomandibular joint and external auditory canal: a case report and literature review

BACKGROUND

Chondroblastomas, which account for approximately 1% of all bone tumors, typically occur in long bones, such as the femur, humerus, and tibia. However, in extremely rare cases, they may also occur in the craniofacial region where the tumor is often found in the squamous portion of the temporomandibular joint (TMJ) and in the temporal bone.

CASE PRESENTATION

This case report describes a large chondroblastoma (diameter, approximately 37 mm) that occurred in the TMJ. The tumor was sufficiently aggressive to destroy the TMJ, mandibular condyle neck, external auditory canal (EAC), mandibular fossa of the temporal bone, and facial nerve. The tumor was completely excised using a pre-auricular approach. The EAC and surgical defect were successfully reconstructed using a temporoparietal fascia flap (TPFF) and an inguinal free fat graft. There was no local tumor recurrence at the 18-month follow-up visits. However, the patient developed sensory neural hearing loss, and his eyebrow paralysis worsened, eventually requiring plastic surgery.

CONCLUSION

Large, invasive chondroblastomas of the TMJ can be completely removed through a pre-auricular approach, and the resulting surgical defect can be reconstructed using TPFF and free fat grafts. However, preoperative evaluation of the facial nerve and auditory function is necessary. Therefore, a multidisciplinary approach is essential.

Rare chondroblastoma of the 6th left rib, video-assisted thoracoscopy resected: one case report and literature review

INTRODUCTION

Chondroblastoma is a rare, benign locally but aggressive bone tumor. It accounts for < 1% of primary bony tumors, and mostly arises from long bones; the rib chondroblastoma is especial rare. Due to its rarity, there are no definitive or standard treatment guidelines.

CASE PRESENTATION

A case of a 24-year-old male with a chondroblastoma located on the 6th posterior left rib. Computed tomography (CT) demonstrated a rib tumor that was a well-defined oval lesion of 20 mm × 18 mm, with lytic bone destruction. The imaging first diagnosis was Langerhans cell histiocytosis (LCH), a giant cell tumor, or other type of neoplasm. The whole tumor and a part of partial rib were resected by video-assisted thoracoscopy surgery (VATS). Pathological and immunohistochemical (IHC) examination made a diagnosis of chondroblastoma. Compared with traditional open thoracic surgery, VATS can achieve the same effects and cause less injury to patient. No postoperative adjuvant therapy was given, and had followed up 23 months after surgery, there was no recurrence or metastasis.

CONCLUSION

Chondroblastoma has a risk of recurrence and metastasis, surgery plays an important role in the treatment of chondroblastoma, VATS can achieve the same outcome as traditional open thoracic surgery with less pain and lung function. Close follow-up is needed postoperative.

"Dry Arthroscopy" is a Valuable Tool in the Excisional Curettage of Chondroblastoma: A Case Series

Introduction:

Chondroblastomas are benign, locally aggressive bone tumors that occur in the epiphysis of young patients, requiring surgical excision. The anatomic locations of these lesions pose technical challenges to the surgeon; their proximity to the articular surface and the physis make surgical approach and visualization difficult. This case series describes the use of intramedullary arthroscopic assistance during excisional curettage of three distal femoral chondroblastomas.

Case Report:

Three patients with distal femoral chondroblastomas underwent excisional curettage with intraosseous “dry” arthroscopic assistance. We describe a two-tunnel technique, using medial and lateral windows so the arthroscope and working instruments could be within the lesion simultaneously; as well as two variations of a single-tunnel technique.

Conclusion:

Achieving adequate ex­­­posure and visualization, while protecting the articular surface and physis, during excision of chondroblastomas, is essential for avoiding local recurrence and complications. “Dry” arthroscopic assistance provides the surgeon with an enhanced view of the tumor and tumor cavity, minimizes invasiveness, and has the potential to reduce complications without compromising the completeness of the excision.

A Novel Technique of Approach in a Skeletally Immature Case of Chondroblastoma - A Case Report

Introduction

Chondroblastoma is a rare benign cartilaginous neoplasm arising in the epiphysis of long bones in young patients. It is an uncommon benign but locally aggressive tumor, mostly located in the secondary centers of ossification. These tumors arise near a joint or growth plate and surgical excision is always challenging.

Case Report

A 13-year-old boy presented with intermittent knee pain, swelling, and limitation of movements for 1 year. On examination, magnetic resonance imaging revealed a hyperintense lesion in distal femoral epiphysis with superior transphyseal extension and inferior thinning of cortex with cartilage breach. Histopathological examination confirmed the diagnosis of chondroblastoma of distal femur. We report a novel technique of approach in a case of distal femoral chondroblastoma in a skeletally immature individual.

Conclusion

The technique we incorporated had an adequate exposure to reach the lesion for a complete curettage and bone grafting. It also reduced further injury to cartilage and physeal plate.

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.

H3.3 K36M Mutation as a Clinical Diagnosis Method of Suspected Chondroblastoma Cases

Objective

Whether H3.3 K36M mutation (H3K36M) could be an approach if the diagnosis of chondroblastoma (CB) patients was indistinct and it was suspected to be unclear clinically.

Methods

We reviewed and compared our clinical experiences of CB cases and some suspected cases, which were not diagnosed distinctly, between 2013 to 2019. A total of 15 male and four female cases included in this study were seperated into two groups, CB group and suspected case (SC) group. The CB group included 13 men and 3 women, with an age range from 9 to 54 (mean age, 22 years old). The SC group included two men and one woman, with the age range from 13 to 25 (mean age, 19 years old). In both groups the patients had been followed‐up until December 2019 and none of the patients had prior treatment history. We evaluated the clinical complaints, radiological features, and clinical‐histological features of the cases and performed an immunohistochemical (IHC) study to detect whether the H3K36M expression of cases was different, consistent with a gene‐mutation analysis.

Results

In both groups, the radiologic features of both groups appeared as round low‐density shadow with a clear edge, pathologic features showed diffuse proliferation of neoplastic cells with multinuclear giant cells. The radiological tumor size of CB group and SC group showed little difference, which was about 29.0*21.6 mm. Clinical‐immunohistochemical features of both groups showed chondroid matrix inside with naïve tumor cells, multinucleated giant cells, and ground substance cells. Most of them showed chondro‐related antibody positive (12 cases) but some of them showed S‐100 negative (four cases). The clear difference of both groups was the result of H3K36M IHC study and gene analysis. In our cases, the CB group showed diffuse H3K36M positive and the SC group showed negative. The gene mutation analysis revealed that H3K36M‐positive CB patients had K36M mutation, which were not found in the SC group. Sanger sequencing showed an A > T substitution at codon 36 of histone H3F3B. No other types of histone H3 mutation was detected in the CB group. Particularly, one of the suspected cases showed a G34W mutation was confirmed to be a giant cell tumor of bone (GCTB).

Conclusions

Our study showed H3K36M immunohistochemistry and gene mutation analysis were specific clinical diagnostic tools to distinguish suspected CB from other giant cell‐rich or cartilage matrix‐diffuse bone tumors. The clinical‐radiological and histomorphological features of patients gave suggestions on whether the H3K36M IHC and gene analysis should be required.

Usefulness of β-catenin expression in the differential diagnosis of osteosarcoma, osteoblastoma, and chondroblastoma

The aim of this study is to assess the usefulness of beta-catenin immunohistochemical expression in the differential diagnosis of osteoid-producing primary tumors of bone. Seventy cases of osteoid-producing tumors of bone (24 conventional osteosarcomas, 18 osteoblastomas, 13 osteoblastoma-like osteosarcomas, 10 chondroblastomas, and 5 chondroblastoma-like osteosarcomas) diagnosed at Istituto Ortopedico Rizzoli were reviewed and evaluated for the intensity, extension, and subcellular distribution of immunohistochemical expression of beta-catenin. A majority of cases (73%, 51 cases) exhibited cytoplasmic and/or membranous positivity in varied degrees of intensity and proportion of positive cells, in the absence of nuclear staining. Fifteen cases (21%) were completely negative, including two osteoblastomas, five chondroblastomas, three conventional osteosarcomas, four osteoblastoma-like osteosarcomas, and one chondroblastoma-like osteosarcoma. A minority of cases (6%) including three osteoblastoma-like osteosarcomas and one osteoblastoma showed focal nuclear beta-catenin positivity with or without concomitant cytoplasmic staining. In the current series, beta-catenin showed not to be useful in the differential diagnosis of osteoid-producing primary bone tumors.

Missed radiographic and clinical findings in a case of non-idiopathic scoliosis resulting from chondroblastoma

PURPOSE

Chondroblastoma is a cartilaginous neoplasm which rarely presents in the spine, where it has been shown to exhibit aggressive behavior. We present a case of a late diagnosis of a T12 chondroblastoma causing paraparesis in an 11-year-old girl. Several missed classical radiographic and clinical features are highlighted.

METHODS

We reviewed clinical, imaging, and pathology data from the time of transfer to our institution, followed by review of all outside clinical records and imaging data from 14 months prior to admission until onset of paraplegia.

RESULTS

The patient was transferred to our center for emergent treatment of a large, expansile, exophytic lesion compressing the spinal cord at T12. Intravenous steroids improved her neurologic status to ASIA Grade B, and an en bloc posterior element resection was performed emergently within 24 h. She rapidly improved to an ASIA Grade E. After obtaining all prior imaging during detailed histopathologic work-up, the final diagnosis was that of spinal chondroblastoma. Subsequent anterior en bloc resection was performed. The patient remains disease-free with a stable, residual scoliosis 7 years postoperatively.

CONCLUSIONS

Detailed review of radiographs is essential for scoliosis patients. Earlier recognition of the "winking owl" sign, a kyphotic sagittal alignment, and more concern about a child with a painful curve may have resulted in earlier diagnosis before the onset of neurologic deficits.

Histone Mutations and Bone Cancers

Primary bone tumors are rare cancers that cause significant morbidity and mortality. The recent identification of recurrent mutations in histone genes H3F3A and H3F3B within specific bone cancers, namely, chondroblastomas and giant cell tumors of bone (GCTB), has provided insights into the cellular and molecular origins of these neoplasms and enhanced understanding of how histone variants control chromatin function. Somatic mutations in H3F3A and H3F3B produce oncohistones, H3.3G34W and H3.3K36M, in more than nine of ten GCTB and chondroblastomas, respectively. Incorporation of the mutant histones into nucleosomes inhibits histone methyltransferases NSD2 and SETD2 to alter the chromatin landscape and change gene expression patterns that control cell proliferation, survival, and differentiation, as well as DNA repair and chromosome stability. The discovery of these histone mutations has facilitated more accurate diagnoses of these diseases and stratification of malignant tumors from benign tumors so that appropriate care can be delivered. The broad-scale epigenomic and transcriptomic changes that arise from incorporation of mutant histones into chromatin provide opportunities to develop new and disease-specific therapies. In this chapter, we review how mutant histones inhibit SETD2 and NSD2 function in bone tumors and discuss how this information could lead to better treatments for these cancers.

Histone Lysine-to-Methionine Mutation as Anticancer Drug Target

Histone modification stands for a vital genetic information form, which shows tight correlation with the modulation of normal physiological activities by genes. Abnormal regulation of histone methylation due to histone modification enzyme changes and histone mutations plays an important role in the development of cancer. Histone mutations, especially H3K27M and H3K36M, have been identified in various cancers such as pediatric DIPG (diffuse intrinsic pontine glioma) and chondroblastoma respectively. "K to M" mutation results overall downregulation of methylation on these lysine residues. Also, "K to M" mutant histones can inhibit the enzymatic activity of the responsible HMT (histone methyltransferase); for instance, SETD2 indicates H3K36 methylation, and Ezh2 represents H3K27 methylation. In-depth analysis of the mechanism of tumor formation triggered by the K to M mutation results in possible targeted therapies. This chapter is going to briefly introduce the mechanism of histone lysine-to-methionine mutation and review the recently identified targeted therapeutic strategies.

Chondroblastoma: Is intralesional curettage with the use of adjuvants a sufficient way of therapy?

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Chondroblastoma represents a rare pathology.

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An aggressive intralesional curettage leads to low recurrence rates.

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Hydrogen peroxide as adjuvant lowers the risk of local recurrence.

Background

Chondroblastoma is a rare benign cartilaginous bone tumor that represents 1–2% of all primary bone tumors. It is characterized by aggressive growth, possible recurrence after surgical treatment and, in rare cases, metastasis. Surgical management is the primary treatment and includes intralesional curettage with or without adjuvants. Local recurrence rates vary between less than 10% up to more than 30%.

Methods

In this retrospective study between 2009 and 2020 we analysed 38 cases of chondroblastoma with a mean follow-up of 27.9 months who underwent a surgical treatment in our institution. Epidemiological data, radiographic and histological examinations, different surgical techniques, complications and local recurrence were evaluated to comment on the question if curettage with or without adjuvants is a sufficient way of therapy.

Results

The study includes 25 male (65.8%) and 13 female (34.2%) patients with a mean age of 17.2 (11–51) years. The most common location of manifestation was the proximal epiphyseal humerus (34.2%), followed by the proximal tibia (26.3%) and the distal femur (15.8%). Joint involvement occurred in 28 patients (73.7%). In all cases intralesional curettage was performed; in 25 cases (65.8%) the resulting cavity was filled with bone substitute, in 7.9% (3 cases) with bone cement and in 10.5% (4 cases) with autogenous bone graft. Adjuvant hydrogen peroxide was used in 64.9% of the cases. The overall recurrence rate was 39.5% (15 cases). The following subgroup analysis showed a recurrence rate of 100% (4/4 cases) after curettage and defect reconstruction with autogenous bone. In the case of intralesional curettage and filling of the cavity with bone substitute but without use of adjuvant the recurrence rate was 50% (4/8 cases). A low recurrence rate of 11.8% (2 cases) was observed in the case of intralesional curettage, using hydrogen peroxide as adjuvant (17 cases) and bone substitute for defect reconstruction.

Conclusions

Chondroblastoma represents a rare pathology. Therapeutically an aggressive intralesional curettage with use of hydrogen peroxide as adjuvant and filling up the defect with bone substitute leads to low recurrence rates.

Solitary long-bone epiphyseal lesions in children: radiologic-pathological correlation and epidemiology

BACKGROUND

Solitary epiphyseal lesions are rare and present with nonspecific imaging features. Knowledge regarding etiologies of pediatric epiphyseal lesions is limited to small studies.

OBJECTIVE

The purpose of this study was to determine the relative incidence of pathologies affecting the pediatric epiphysis based on biopsy-proven cases with imaging.

MATERIALS AND METHODS

We conducted a retrospective review of imaging studies including the terms "biopsy" or "resection" and entities known to affect the epiphysis and cross-referenced these with pathology reports, recording the relevant clinical data. Two radiologists performed comprehensive imaging review and recorded relevant features.

RESULTS

Forty-nine children and adolescents met inclusion criteria. The long-bone epiphyseal lesion etiologies included chondroblastoma (n=22, 45%), nonspecific nonmalignant pathology (n=11, 22%), osteomyelitis (n=9, 18%), lymphoma (n=2, 4%) and 1 case of each of aneurysmal bone cyst, chondrosarcoma, enchondroma, hemangioendothelioma, and non-Langerhans cell histiocytosis. Median age was 13.1 years old (range 1.5-18.6 years). We performed comparative analysis of the two most common lesions in our series, chondroblastoma and osteomyelitis. Chondroblastoma was significantly more likely to be peripherally located (94% vs. 33%, P=0.002) and to demonstrate a discrete T1-weighted hypointense rim (94% vs. 33%, P=0.002); there were no significant differences in enhancement or intrinsic signal properties. Children with chondroblastoma were older (15.1 years vs. 7.3 years, P=0.001), and chondroblastoma lesions were significantly larger, with mean maximum lesion diameter of 25 mm (interquartile range [IQR] 20-30) vs. 12 mm (IQR 11-18) (P=0.001) and lesion volumes of 4.4 mL (IQR 2.4-7.9) vs. 0.4 mL (IQR 0.2-1.4) (P=0.01).

CONCLUSION

This study reports the relative frequency of pathology of pediatric solitary epiphyseal lesions and describes several features that might assist in differentiating between chondroblastoma and osteomyelitis.

Chondroblastoma's Lung Metastases Treated with Denosumab in Pediatric Patient

Chondroblastoma is a rare benign chondrogenic tumor that occurs in skeletally immature patients between ages 10 and 20 years old. In literature are reported few cases of lung metastases, mainly occurred after surgery or local recurrences. There is no evidence on the pathogenesis of lung metastasis, as well as pulmonary disease course. Few treatments for metastases with aggressive behavior were based on chemotherapy regimen employed in other sarcoma with no results or not satisfying ones. Denosumab is approved for treatment of giant cell tumors and it is under investigation for other giant cell-rich bone tumors. Here, we report a case of a 16-year-old male chondroblastoma of the left humerus with bilateral lung metastases at presentation and progressing during follow-up, treated with denosumab for almost 2 years. We confirm that denosumab treatment can be effective in controlling chondroblastoma metastasis and it has been a safe procedure in an adolescent patient.

Temporal Bone Chondroblastoma: a Rare Entity

INTRODUCTION

Chondroblastoma is an uncommon benign, locally destructive tumor that usually arises from epiphyses of the long bones. Temporal bone chondroblastoma is an extremely rare occurrence. Chondroblastoma arise from immature cartilage cells and it may display certain malignant features by invading surrounding structures and metastasizing to adjacent sites.

AIM

To present a case of extradural temporal bone chondroblastoma and discuss the clinical presentation, radiographic findings, histology and particularly the surgical management of the case.

CASE REPORT

We report a case of a 31-year-old man who presented with a painless left temporal swelling and left sided hearing loss for four months. Computed tomography (CT) scan revealed an aggressive mass involving the left preauricular region with temporal mastoid bone erosion. Magnetic resonance imaging (MRI) showed an extra-axial left temporal mastoid mass pushing the left temporal lobe superiorly. The patient underwent complete excision of the temporal bone tumor. The final histopathological diagnosis was in keeping with chondroblastoma.

CONCLUSION

Temporal bone chondroblastoma is rare but an aggressive condition. Complete tumor resection via an appropriate approach that enables adequate exposure will lead to a favorable outcome.

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.

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.

Temporal Bone Chondroblastoma: Systematic Review of Clinical Features and Outcomes

OBJECTIVE

Chondroblastoma is an uncommon benign neoplasm of cartilaginous origin usually involving the long bones. The temporal bone is a rare location for this tumor. The clinical profile, optimal medical and surgical management, and outcomes of treatment for temporal bone chondroblastoma remain unknown.

METHODS

We performed a systematic review of the SCOPUS, PubMed, and CENTRAL databases for case reports and case series on patients with histopathologically proven temporal bone chondroblastoma. Data on demographics, clinical manifestation, surgical management, adjuvant treatment, and outcome on last follow-up were collected.

RESULTS

A total of 100 cases were reported in the literature, including one described in the current study. The mean age of patients was 42.3 years (range, 2-85 years), with a slight male predilection (1.3:1). The most common clinical manifestations were otologic symptoms (e.g., hearing loss [65%], tinnitus, and otalgia) and a palpable mass. Surgical excision was performed in all cases, with gross total excision achieved in 58%. Radiation therapy was performed in 18% of cases, mostly as adjuvant treatment after subtotal excision. There were no deaths at a median follow-up of 2 years. Among the patients with detailed status on follow-up, 58% had complete neurologic recovery, 38% had partial recovery, and 4% had progression of symptoms as a result of tumor recurrence.

CONCLUSIONS

Temporal bone chondroblastoma has a distinct clinical profile from chondroblastoma of long bones. Surgery is the mainstay of treatment, and radiation therapy may be given after subtotal excision. Outcomes are generally favorable after treatment.

Navigation-assisted surgery for chondroblastoma arising in the femoral head: A case report

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We reported the first case to use navigation for the femoral head chondroblastoma.

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Visualization of tumor on navigation helps to minimize unnecessary destruction.

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Navigation assistance is an optimal surgical option for chondroblastoma in the femoral head.

Introduction

Surgery for chondroblastoma in the femoral head is challenging due to its inaccessibility, with high risk of local recurrence and poor functional outcomes reported. We herein report the first case of chondroblastoma in the femoral head treated by navigation-assisted surgery.

Presentation of case

A 12-year-old girl presented with persistent left hip pain and limited hip range of motion. Imaging studies revealed a well-defined osteolytic lesion in the left femoral head accompanied by extensive intra-osseous oedematous change. The bone lesion was radiologically diagnosed as chondroblastoma. With navigation assistance, curettage was performed via the anterior approach. The tumor was fully accessible from the femoral neck. After curettage, the bony defect was filled with bone substitute. The pathological diagnosis was chondroblastoma. The post-operative course was uneventful. Thirty months postoperatively, the patient was free of pain with full hip range of motion, and MR images showed no evidence of recurrence or osteonecrosis.

Discussion

This case is the first to use a navigation system for the treatment of chondroblastoma in the femoral head. The navigation system can minimize damage to intact structures and increase the efficiency of curettage by visualizing access to the tumor.

Conclusion

Navigation assistance is an optimal surgical option for chondroblastoma in the femoral head.

[Molecular pathology in the diagnosis of bone tumors: current concepts]

The integrative evaluation of histology and corresponding imaging is essential for the classification of bone tumors. Until a few years ago, there were hardly any molecular markers that could be used for diagnostic purposes. However, exome- and genome-wide sequencing analyses have since uncovered a number of tumor-specific aberrations that can be very helpful in ambiguous cases. In addition to characteristic gene mutations (e.g. H3F3A and H3F3B in giant-cell tumors and chondroblastomas), the detection of fusion transcripts (e.g. structural rearrangements in the AP‑1 transcription factors FOS and FOSB in osteoid osteomas and osteoblastomas) plays an increasing role. The article gives an overview of the current state of knowledge of the most important alterations in bone tumors.

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.

Secondary aneurysmal bone cysts and associated primary lesions: imaging features of 49 cases

PURPOSE

To describe the imaging, anatomic, and clinical features of a series of secondary aneurysmal bone cysts (ABC) and to ascertain their most commonly associated primary bone lesions.

METHODS

Forty-nine cases of histopathologically proven secondary ABCs were retrospectively reviewed. Demographic data and clinical history were obtained. Radiographic, computed tomographic, magnetic resonance, and nuclear medicine imaging were analyzed. Lesion location, imaging characteristics, and associated primary lesions were documented. Linear regression analysis and Chi-squared testing was performed for statistical analysis.

RESULTS

Twenty-four males and 25 females were included, with an age range of 8-79 years (mean 29.7 + - 4.5 years). Eleven types of primary bone lesion were identified, with giant-cell tumor (n = 17, 35%), chondroblastoma (n = 11, 22%), fibrous dysplasia (n = 6, 12%), osteoblastoma (n = 4, 8%) and osteosarcoma (n = 4, 8%) being the most frequent. The lesions involved chiefly the long bone epiphyses (n = 25, 51%). Secondary ABC imaging findings and locations most closely approximated those of their primary counterparts, although fluid-fluid levels were seen at a higher frequency than previously reported in primary chondroblastoma (9/11, 82%), fibrous dysplasia (2/6, 33%), osteoblastoma (4/4, 100%), osteosarcoma (3/4, 75%), and chondromyxoid fibroma (1/2, 50%).

CONCLUSION

The most common primary lesions associated with secondary ABC were giant cell tumor and chondroblastoma, located in the long bone epiphyses. The majority of the secondary ABCs demonstrate predominant imaging characteristics typical of the primary bone lesions, but with a higher presence of fluid-fluid levels.

Non-vascularised Fibular Autograft for Reconstruction of Paediatric Bone Defects: An Analysis of 10 Cases

Aim and objective

Fibular autograft is a known technique for the reconstruction of traumatic and non-traumatic bone defects in both adult and paediatric populations. We aim to describe our outcomes using various stabilisation methods for non-vascularised fibular autograft to reconstruct both benign and malignant tumours in a paediatric population in a National Paediatric Centre over the past 14 years.

Materials and methods

This was a retrospective review of 10 paediatric cases with non-traumatic primary bone defects in a National Paediatric Centre. Criteria for inclusion were all non-traumatic primary bone defects requiring reconstruction with a non-vascularised fibular autograft in the diaphyseal or metaphyseal regions of the bone. The primary outcome measures were union and time to union (weeks). Time to union was illustrated using Kaplan–Meier curves. Secondary outcome measures included postoperative fracture, infection (deep and superficial), time to full weight-bearing and all-cause revision surgery.

Results

The mean length of follow-up was 63 months for the entire cohort (9–168, SD = 48.6). There was no loss to follow-up. Six lesions were located in the tibia, two in the femur and the remaining two were located in the ulna and third metacarpal. Union was ultimately achieved in 8 of the 10 patients using this donor autograft. The mean time to union was 28 weeks (10–99, SD = 29.8). There were four complications of autograft fracture. The mean time to fracture was 17 weeks (9–32, SD = 10.71). In all four of these cases, the patient achieved union at final follow-up. There were two superficial and two deep infections recorded. Three resolved with the use of antimicrobial therapy and one deep infection ultimately required insertion of an intercalary prosthesis to treat the infected non-union of the fibular graft site.

Conclusion

The use of non-vascularised fibular autograft for the reconstruction of tumours is an effective surgical technique in a paediatric cohort. We report the largest known series of malignant paediatric tumours treated with this technique to date.

Clinical significance

Non-vascularised fibular autograft is successful in the reconstruction of large bone defects secondary to malignant paediatric bone tumours.

How to cite this article

Sheridan GA, Cassidy JT, Donnelly A, et al. Non-vascularised Fibular Autograft for Reconstruction of Paediatric Bone Defects: An Analysis of 10 Cases. Strategies Trauma Limb Reconstr 2020;15(2):84–90.

Immunohistochemical analysis of 36 cases of chondroblastomas: A single institutional experience

Chondroblastoma is a relatively uncommon, primary benign bone tumor, frequently identified in young individuals. Despite its classical radiologic and histopathological features, at times, it is fraught with a diagnostic challenge, especially differentiating it from a giant cell tumor of bone (GCTB); an osteosarcoma and a chondrosarcoma. Lately, few studies have shown the diagnostic utility of immunohistochemical (IHC) expression DOG1 antibody in chondroblastomas. The present study was undertaken to evaluate IHC expression of S100 protein, DOG1 and p63 in 36 chondroblastomas. From January 2013 to July 2019 (6-year duration), 106 chondroblastomas were diagnosed, with IHC staining performed in 36 cases. Conventional Hematoxylin and Eosin stained microsections and IHC stained sections were reviewed in 36 cases. IHC staining of p63 (intranuclear), S100 protein (nuclear and cytoplasmic) and DOG1 (cytoplasmic membranous) was recorded in various cases. Seventy-four tumors occurred in males and 32 in females, within age-range of 7-55 years (average = 18.6), frequently in tibia (33/106; 31.1%), followed by femur (26, 24.5%) humerus (22, 20.7%), calcaneum (5) and scapula (4). IHC staining for S100P was positive in 33/36cases (91.7%); DOG1 in 16/19 (84.2%) cases and p63 in 10/15cases (66.6%). DOG1 immunostaining was negative in 25 various other tumors. Sensitivity and specificity for S100P, DOG1and p63 in chondroblastomas was (91.6%, 59.3%); (84.2%, 100%) and (66.6%, 46.6%), respectively. P63 was positively expressed in 15/27 (55.5%) GCTBs. S100 protein and DOG1 can be utilized for a confirmatory diagnosis of a chondroblastoma, especially for differentiating it from its other differentials, such as GCTB, in view of certain associated therapeutic implications. P63 is not useful in that scenario.

Chondroblastoma of the patella with pathological fracture in an adolescent: a case report

BACKGROUND

Chondroblastoma is a rare primary bone tumor of young people that generally occurs in the epiphyseal plate of long bones. To date, only 13 cases of patella with pathological fracture in chondroblastoma have been previously published.

CASE PRESENTATION

A 15-year-old male patient presented with acute pain in the left knee after an injury occurred while playing basketball. Plain radiographs and computed tomography showed a pathological fracture of the left patella with an osteolytic lesion (1.5 × 2 × 3 cm). Magnetic resonance imaging revealed an expansile lesion within the patella with a slightly high signal on the T1-weighted image, a high signal on the T2-weighted image and soft tissue swelling in front of the patella. A ^m99Tc bone scintigraphy revealed moderate uptake. The preoperative diagnosis was chondroblastoma. This patient underwent intralesional meticulous extended curettage, adjuvant high-speed burr, 95% alcohol and electrotome treatment, autogenous iliac crest bone grafting, and internal fixation. A postoperative pathological diagnosis was chondroblastoma. The patient's function was satisfactory, and there was no sign of tumor recurrence. The internal fixator was good, with no loosening or migration observed at the last follow-up at 20 months after surgery.

CONCLUSIONS

Rarely, chondroblastoma of the patella can present with acute pain due to pathological fracture. We present the 14th such case in the literature to associate patellar chondroblastoma with pathological fracture. The patient was treated with curettage, inactivation, autogenous bone grafting, and internal fixation. A satisfactory therapeutic effect was obtained. This case may be beneficial to the diagnosis and treatment of chondroblastoma patella.

Mutation-driven epigenetic alterations as a defining hallmark of central cartilaginous tumours, giant cell tumour of bone and chondroblastoma

Recently, specific driver mutations were identified in chondroblastoma, giant cell tumour of bone and central cartilaginous tumours (specifically enchondroma and central chondrosarcoma), sharing the ability to induce genome-wide epigenetic alterations. In chondroblastoma and giant cell tumour of bone, the neoplastic mononuclear stromal-like cells frequently harbour specific point mutations in the genes encoding for histone H3.3 (H3F3A and H3F3B). The identification of these driver mutations has led to development of novel diagnostic tools to distinguish between chondroblastoma, giant cell tumour of bone and other giant cell containing tumours. From a biological perspective, these mutations induce several global and local alterations of the histone modification marks. Similar observations are made for central cartilaginous tumours, which frequently harbour specific point mutations in the metabolic enzymes IDH1 or IDH2. Besides an altered methylation pattern on histones, IDH mutations also induce a global DNA hypermethylation phenotype. In all of these tumour types, the mutation-driven epigenetic alterations lead to a highly altered transcriptome, resulting for instance in alterations in differentiation. These genomic alterations have diagnostic impact. Further research is needed to identify the genes and signalling pathways that are affected by the epigenetic alterations, which will hopefully lead to a better understanding of the biological mechanism underlying tumourigenesis.

[Challenges in the diagnosis of cartilage tumors : Morphological spectrum and molecular markers]

The morphological and clinico-biological spectrum of chondrogenic tumours is wide. Given the diversity of therapeutic approaches, the correctness of the histological diagnosis is of major importance. The aim of this review is to provide insights into the challenges and limitations of diagnostic approaches restricted to morphology and to underscore the importance of an interdisciplinary dialogue between surgeons, radiologists and pathologists. Beyond this, the value of molecular analyses introduced in bone tumor diagnostics in recent years is discussed.

Chondroblastoma in pelvis and extremities- a signle centre study of 177 cases

Introduction

Chondroblastoma is a rare benign bone tumour that usually occurs in children and young adults. They are cartilaginous tumours arising in the epiphysis or apophysis of a long bone. The tumour is classified as benign, although rare cases of pulmonary metastases have been reported. The aims of this study were to describe clinical, radiographic characteristics of chondroblastoma; to analyse the local recurrence rate and complications associated with surgery.

Material and methods

This retrospective study included 177 patients, who had been diagnosed with a chondroblastoma in extremity between 1990 and 2015.

Results

The most common site was proximal tibia 20%, followed by proximal humerus 19%, proximal femur 18%, distal femur 16% and foot 15%. One patient has died of the disease and one patient is alive after being operated for lung metastases. There was local recurrence in 25/177 (14%) patients. The median time to local recurrence was 10 months (range 3–158 months). The most common site for local recurrence was proximal tibia (22.2%). The proximal femur was the location in 32/178 (18%) of the cases. 18/32 (56%) were in the greater trochanter and 14/32 (44%) in the femoral head. The mean age was lower in tumours located in femoral head when compared to the greater trochanter; 19.5 years and 13.9 years respectively (p = =0.004). Tumours located in greater trochanter were all curetted without further complications. Local recurrence was seen more often in femoral head tumours, though without statistical significance; 3/14 (21%) and none, respectively (p = =0.073).

Conclusions

Chondroblastoma is a rare benign to intermediate grade bone tumour with a potential to metastasise. Femoral head chondroblastoma is rare, presenting 4.5% of all chondroblastoma cases. Around 50% of the chondroblastoma in femoral head. occur in patients with open growth plates.