Prostaglandin levels of primary bone tumor tissues correlate with peritumoral edema demonstrated by magnetic resonance imaging

The CT and MRI features of benign calvarium and skull base osteoblastoma

OBJECTIVE

We retrospectively reviewed the CT and MRI features of patients with benign osteoblastoma in the calvarium and skull base (CSBOB).

METHODS

Nine cases of pathologically confirmed benign CSBOB were analysed retrospectively. The patients had undergone CT and/or MRI. Tumour location, size, and imaging features were reviewed and recorded.

RESULTS

The patients included four males and five females with a mean age of 27.0 years (age 14-40 years). The tumours were located in the frontal bone in 3 patients, the occipital bone in 3 patients, and in the parietal bone, sphenoid bone, and skull base in 1 patient each. On CT, the tumours measured 5.1 ± 3.3 (1.8-8.4) cm. Seven tumours were shown to have caused expansile bony destruction with an eggshell appearance and varying degrees of calcification or matrix mineralization. Multiple septa were observed in 5 tumours. Intracranial growth was observed in 5 tumours. On MRI, 7 tumours showed heterogeneous hypo- to isointensity on T1WI. Heterogeneous high signal patterns with low signal rims and septa were observed in 6 tumours on T2WI, and 4 showed a fluid-fluid level. On contrast-enhanced imaging, 6 tumours showed peripheral and septal enhancement, and 2 showed the dural tail sign.

CONCLUSIONS

Benign CSBOB is a rare tumour characterized by expansile bony destruction, septa, a sclerotic rim and calcification or matrix mineralization on CT and MRI.

ADVANCES IN KNOWLEDGE

The findings from this study contribute to a better understanding of benign CSBOB and provide valuable imaging features that can aid in its diagnosis and differentiation from other tumours in the calvarium and skull base.

Multimodal Imaging Evaluation and Clinical Progress of Spinal Osteoblastoma: A Comprehensive Review

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

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.

Spinal osteoblastoma: a retrospective study of 35 patients' imaging findings with an emphasis on MRI

Objective

To investigate the values of multimodal imaging approaches in the diagnosis of spinal osteoblastomas with an emphasis on MRI findings.

Materials and methods

We retrospectively evaluated the imaging findings of 35 patients with spinal osteoblastomas. The imaging methods included radiography, whole-body bone scintigraphy (WBBS), CT and MRI.

Results

Radiography detected 87.1% (27/31) of the lesions; WBBS demonstrated increased radionuclide activity in all the lesions. CT could precisely show and localize all niduses, and calcification was always detected. MRI usually could adequately delineate the niduses of osteoblastomas, especially on T2WI (88.2%; 30/34). 71.9% (23/32) of osteoblastomas were surrounded with moderate or extensive bone marrow edema (BME) with soft tissue edema (STE). STE always extended along the muscle bundle adjacent to the lesion; there was no subcutaneous fat involvement. BME was eccentrically distributed in the vertebral body and spread inward from the sides of the nidus. The extent of BME in the vertebral body tended to be inversely proportional to the distance from the nidus. In addition, rare magnifications of osteoblastoma including multifocal diseases (n = 2), vertebra plana (n = 1) or with aneurysmal bone cysts (n = 6) were also observed in our study.

Conclusions

In patients showing moderate or extensive BME together with STE on MRI, both CT and MRI should be used to confirm nidus presence. The above-mentioned characteristics of edema on MRI of patients with spinal osteoblastoma are helpful in not only localizing the nidus, but also enhancing the diagnostic confidence.

Typical and Atypical Radiographic Features of Symptomatic Osteoblastoma in the Spine

BACKGROUND

Spine osteoblastomas (OBs) are relatively rare. In contrast to osteoid osteoma, radiologic and clinical manifestations of OB can be varied and atypical. Typical radiographic features in spinal OB include peritumoral bone sclerosis, bone marrow edema, and soft tissue edema. Atypical radiographic features include lesions involving ≥3 segments, lesions with extensive (≥3 segments) bone sclerosis, excessive edema (≥3 segments) of soft tissue and bone marrow, no intralesional calcification, and location in the vertebral body only. The aim of this study was to identify typical and atypical features of OB.

METHODS

Pretreatment computed tomography scans and magnetic resonance imaging were reviewed retrospectively. Percutaneous biopsies were performed to confirm pathology in atypical cases.

RESULTS

A total of 50 images from patients with diagnosed OB were reviewed. Atypical radiographic features were found in 18 cases (36%). Pathologic diagnosis was confirmed as OB in 86.2% (25/29) cases after percutaneous computed tomography-guided biopsy.

CONCLUSIONS

Our results show that >30% of spinal OB cases might have atypical radiographic features. In cases with atypical radiographic features, computed tomography-guided biopsies are recommended.

MR Imaging of Osteoid Osteoma: Pearls and Pitfalls

Osteoid osteoma (OO) is a benign bone neoplasm consisting of a central prostaglandin-secreting nidus surrounded by a zone of reactive sclerosis. The diagnosis is suspected in children and young adults with longstanding nighttime pain that is relieved by salicylates or nonsteroidal anti-inflammatory drugs. Early studies suggested that computed tomography had a higher sensitivity and specificity in the diagnosis of OO compared to magnetic resonance imaging (MRI). More recent literature suggests MRI done with dynamic postcontrast imaging to be equal to or slightly better at detecting the nidus of OOs, particularly the ones in atypical locations. Being able to evaluate for OO utilizing MRI is important given that the majority of these lesions occur in younger patients, in whom there is greater concern to limit ionizing radiation. Furthermore, patients with atypical OOs often receive an MRI if radiographs are not suggestive of the diagnosis. Therefore, it is important for radiologists to be aware of the imaging features that can help make the diagnosis on MRI.

Imaging algorithm and multimodality evaluation of spinal osteoblastoma

Background

To analyze the features of CT, MRI and PET/CT and their diagnostic value for spinal osteoblastomas (OBs).

Methods

The radiological and clinical data of 21 patients with histopathologically-confirmed spinal OBs were analyzed retrospectively.

Results

Sixteen of the 21 cases were benign and 5 were aggressive OBs. Tumors were located in the lumbar (n = 11), cervical (n = 4), thoracic (n = 5), and sacral (n = 1) spinal regions. Nineteen cases were centered in the posterior elements of the spine, 13 of which extended into the vertebral body. Punctate or nodular calcifications were found in all cases on CT with a complete sclerotic rim (n = 12) or incomplete sclerotic rim (n = 8). The flare phenomenon (indicative of surrounding tissue inflammation) was found in 17/21 cases on CT, thin in 11 cases and thick in 6 cases, and in 19/19 cases on MRI, thin in 1 case and thick in 18 cases. On ¹⁸F-FDG PET/CT, all cases (8/8) were metabolically active with the SUVmax of 12.3–16.0; the flare sign was observed in 8 cases, including 7 cases of hypometabolism and 1 case of coexistence of hypermetabolism and hypometabolism. Based on CT, 3, 12, and 6 cases were classified as Enneking stage 1, 2 and 3, respectively. Of 19 cases with MRI, 1 and 18 cases were classified as Enneking stage 2 and 3, respectively.

Conclusions

Spinal OB has multiple unique characteristic radiological features. Although a larger sample size is needed, combining CT, MRI and PET may be beneficial to optimize preoperative diagnosis and care of patients with OBs.

Lumbar Extraosseous Intraforaminal Osteoblastoma: Case Report and Review of the Literature

BACKGROUND

Osteoblastomas are rare primary bone tumors with a predilection for the spine. The extraosseous growth pattern is rare, and to our knowledge, only 2 cases of fully extraosseous osteoblastomas have been previously reported.

CASE DESCRIPTION

A man aged 36 years presented with a 7-month history of low back pain radiating to the gluteal area. On examination, a typical L5 radiculopathy was noted. The radiologic examinations conducted in the previous months pointed out the rapid growth of an extraosseous mass occluding the right L5-S1 foramen. Partial laminectomy was performed to achieve gross total resection. Histological analysis was consistent with osteoblastoma.

CONCLUSIONS

Osteoblastomas with extraosseous extension are uncommon, and an exclusively extraosseous presentation is anecdotal. This can lead to preoperative misdiagnosis when typical radiologic characteristics of bone-forming tumors are missing. We describe the case of an extraosseous lumbar osteoblastoma whose clinical and radiologic presentation was suggestive of malignancy.

Edema Surrounding Benign Tumors and Tumor-Like Lesions

Objective

To explore the incidence and significance of intra- and extra-osseous edema associated with benign tumors and tumor-like diseases.

Methods

Magnetic resonance imaging (MRI) data from 300 benign osseous tumors and tumor-like diseases diagnosed by pathology were retrospectively reviewed. Borderline tumors, cases associated with pathological fractures, and skull lesions were excluded from the study. Bone marrow and soft tissue edema were defined on T2WI with fat suppression on MRI in all cases. The incidence rate of edema in benign tumors and tumor-like diseases was determined using the χ ² test. The preoperative diagnoses were reviewed, and the effect of edema on the differential diagnosis of benign and malignant tumors was analyzed.

Results

The incidence rate of bone marrow and soft tissue edema associated with benign tumors and tumor-like diseases was 35.7% (107/300), including 84.4% (27/32) Langerhans cell histiocytosis, 86.4% (19/22) osteoblastoma, 93.9% (31/33) osteoid osteoma, and 85.2% (23/27) chondroblastoma cases. There was no statistically significant difference in the incidence of edema among the four diseases (χ ² = 1.7, P > 0.05). Of 107 cases associated with edema, 49 (45.8%) were misdiagnosed as malignant tumors by MRI preoperatively.

Conclusion

Bone marrow and soft tissue edema are a common finding associated with benign bone tumors and tumor-like diseases, and they are frequently detected in Langerhans cell histiocytosis, osteoblastoma, osteoid osteoma, and chondroblastoma.

Intra-articular osteoid osteoma accompanied by extensive bone marrow edema. A clinical and micro-morphological analysis

•

A series of patients with intra-articular osteoid osteoma (OO) is demonstrated.

•

Extensive and persistent bone marrow edema syndrome masked the correct diagnosis.

•

No consistent patterns of impaired bone mineral status could be confirmed in these patients.

•

Nidus specimens displayed significantly higher mineralization heterogeneity determined by qBEI.

Osteoid osteoma (OO) is a benign bone tumor producing non-mineralized bone matrix (i.e., osteoid). While peritumoral edema is commonly found in OO, extensive bone marrow edema has been reported less frequently. Furthermore, the micro-morphological characteristics of the nidus and its central calcification remain unclear. In this study, a consecutive series of four patients suffering from extensive bone marrow edema triggered by intra-articular osteoid osteoma underwent clinical examination, magnetic resonance imaging (MRI) and computed tomography (CT) as well as dual-energy X-ray absorptiometry (DXA) and laboratory bone turnover analyses. The obtained resection specimens were processed by undecalcified histology and were subsequently analyzed by light microscopy and quantitative backscattered electron imaging (qBEI). We report an entity of intra-articular osteoid osteoma in the knee and foot, in which an extensive and persistent bone marrow edema syndrome masked the correct diagnosis. While metabolic bone diseases were excluded in all cases, the reassessment of the patients’ clinical history including pain characteristics (nocturnal, aspirin sensitivity) led us to perform additional CT, where the tumor was diagnosed. The micro-morphological analysis of the OO biopsies revealed that the nidus was surrounded by hyperosteoidosis, while central mineralization was detected in all cases. This mineralized area showed a significantly higher mineralization heterogeneity than the surrounding trabecular bone and more disorganized collagen fibers detected by qBEI and polarized light microscopy, respectively. Taken together, our results indicate that osteoid osteoma should be considered when persistent and extensive, peri-articular bone marrow edema is diagnosed. The central calcification that is found inside the nidus in conventional imaging was mirrored by bone matrix with a heterogeneous mineralization pattern.

A rare case of a medullary, multifocal lesion in the distal radius

In multifocal findings, the possibility of multifocal osteoid osteomas should be considered and this case helps us to be attentive for the unusual radiographical presentation of osteoid osteoma.

Tumour response of osteosarcoma to neoadjuvant chemotherapy evaluated by magnetic resonance imaging as prognostic factor for outcome

PURPOSE

This study evaluated the feasibility of computed magnetic resonance imaging (MRI) volumetry in conventional osteosarcomas. Secondly, we investigated whether computed volumetry provides new prognostic indicators for histological response of osteosarcomas after neoadjuvant chemotherapy.

METHODS

In a retrospective cohort study, data from the Vienna Bone Tumour Registry was used. MR images from 14 patients (male:female = 1.8, mean age 19 years) were analysed prior to and after neoadjuvant chemotherapy according to current therapy regimens. Histological response to chemotherapy was graded according to the Salzer-Kuntschik classification. Computed volumetry was performed for the intraosseous part, as well as the soft-tissue component and the tumour as a whole.

RESULTS

In a setting of appropriate radiological equipment, the method has been considered to be well implementable into clinical routine. The mean tumour volume prior to chemotherapy was 321 (±351) ml. In good responders (n = 6), overall tumour volume decreased by 47% (p = 0.345), whereas poor responders (n = 8) showed a 19% decrease (p = 0.128). Neoadjuvant multidrug therapy remarkably changed the tumour composition. This is seen in a decrease of the mean ratio of soft-tissue to intraosseous tumour volume from 8.67 in poor responders and 1.15 in good responders to 1.26 and 0.45 (p = 0.065), respectively. Interestingly, the bony compartment of good responders showed a volume increase during neoadjuvant chemotherapy (p = 0.073). However, we did not find prognostic markers for histological tumour response to pre-operative chemotherapy.

CONCLUSIONS

Separated volumetry of tumour segments revealed interesting insights into therapy-induced growth patterns. If verified in a larger study population, these results should be taken into account when planning ablative surgery.

Clinical characteristics and treatment options for two types of osteoblastoma in the mobile spine: a retrospective study of 32 cases and outcomes

PURPOSE

A retrospective study of 32 patients with osteoblastoma (OBL) in the mobile spine was performed to analyze the clinical characteristics of two types of spinal OBL. We also aimed to find influential factors for OBL in the mobile spine.

METHODS

Between 2002 and 2011, 32 patients with either conventional osteoblastoma (CO) or aggressive osteoblastoma (AO) in the mobile spine were treated in our center. All patients were treated with either total excision or subtotal excision + postoperative radiotherapy. The mean follow-up was 45.8 (18-128) months. Clinical data and surgery efficacy were analyzed to search for clinical characteristics of two subtypes of spinal OBL and discuss the possible factors influencing relapse.

RESULTS

There is significant difference between CO and AO in tumor size (p < 0.0005), preoperative alkaline phosphatase (ALP, p < 0.0005) and intraoperative blood loss (p = 0.013). Multivariate logistic regression was used to find the influential factors for relapse and the results were: preoperative ALP, b = 0.023, p = 0.029; surgery protocol, b = -7.597, p = 0.007; tumor size, ≥3/<3, b = 24.805, p < 0.0005; age, b = 0.054, p = 0.632; and pathology type, b = 1.998, p = 0.34.

CONCLUSIONS

Tumor size, preoperative ALP and CT images were helpful for distinguishing AO from CO. The difference in intraoperative blood loss between CO and AO is mainly attributed to the size of the lesion. Preoperative ALP, surgery protocol and tumor size (≥3/<3) were considered to significantly influence relapse of spinal OBL.

Intraarticular osteoblastoma with subluxation of the hip joint

PATIENT

Male, 5 FINAL DIAGNOSIS: Osteoblastoma Symptoms: -

MEDICATION

- Clinical Procedure: - Specialty: Oncology.

OBJECTIVE

Rare disease.

BACKGROUND

Osteoblastomas are relatively uncommon bone tumors that account for <1% of all bone tumors. They usually occur in the medullary region of the bone. As such, intraarticular osteoblastomas are quite rare.

CASE REPORT

In this report, we present the case of a 5-year-old boy who presented with vague pain and subluxation of the hip joint due to an intraarticular osteoblastoma. Radiological examinations showed an irregular calcified mass lesion in the hip joint. The final diagnosis of osteoblastoma was made by histological examination. The patient's symptoms completely subsided following surgical removal of the tumor.

CONCLUSIONS

Osteoblastomas can occur in the intraarticular region. Although quite rare, osteoblastoma should be considered among the differential diagnoses for patients with pain and subluxation of the hip joint.

Osteoid osteomas: a pain in the night diagnosis

Osteoid osteoma is a common benign bone-forming lesion that is composed of a nidus of vascular osteoid tissue and woven bone lined by osteoblasts. It is frequently associated with considerable surrounding inflammation. The diagnosis is usually straightforward when imaging reveals a radiolucent nidus surrounded by variable degrees of reactive sclerosis. However, the diagnosis can be elusive when osteoid osteomas occur in atypical locations, as they may have a nonspecific and misleading appearance on different imaging modalities, particularly on MRI. The purpose of this pictorial essay is to review the typical and atypical features of osteoid osteomas on different imaging modalities, and the appearance of osteoid osteomas in different locations. We also review growth disturbances caused by osteoid osteomas and potential mimickers, with imaging characteristics that can aid in diagnosis.

Chondroblastoma of the femoral neck as a cause of hip synovitis

Chondroblastoma is a rare benign chondroid bone tumor, which typically arises from the epiphysis of a long tubular bone. We present a 13-year-old girl with persistent hip synovitis caused by a chondroblastoma that arose from the femoral neck (metaphysis) and uniquely extended extraosseously into the hip joint. Computed tomography scan clearly demonstrated a tumoral lesion of the left femoral neck and a periosteal reaction along the anterior cortex of the femur, distal to the legion. Magnetic resonance imaging showed reactive synovitis with marked joint effusion of the hip and an extensive edema in the proximal femur and the surrounding soft tissues. Aneurysmal bone cysts formation secondary to chondroblastoma was confirmed by histologic examinations of the excised specimens. Complete relief of pain and an improvement in the range of movement of the hip joint was obtained after surgical resection of the tumor.

Osteoid osteoma of the talus presenting as posterior ankle impingement: case reports

Level of Evidence: V, Expert Opinion

A clinicopathologic correlation in osteoblastoma of the spine in a child

Spinal osteoblastomas are considered benign tumors but can be locally aggressive. Patients usually present with pain and undergo radiologic and histologic work-up to establish a diagnosis. Osteoblastomas have discordant appearances on CT scans and MRI because of the inflammatory response seen on MRI that characterizes these tumors - the "flare" phenomenon. Solely using MRI can lead to over-resection, as signal abnormality may include areas devoid of tumor. There are a few reports of this phenomenon in the radiology literature, but to our knowledge, there are none in neurosurgery journals. We report an 11-year-old boy who presented with back pain and radiculopathy with an osteoblastoma at the L4 level. We totally excised the lesion to definitively treat the patient but also, based on MRI findings, differentially biopsied portions of the lesion and correlated them to the imaging studies, to confirm that the intense reactive portion of the lesion was devoid of tumor cells.

Imaging of tumors in the ankle and foot

Common bone and soft tissue tumors in the foot and ankle are described in this article, and x-ray and magnetic resonance imaging characteristics are given. Ultrasound can be used for limited indications only, noting that ultrasound features are nonspecific. Of the bone and soft tissue tumors, approximately 7% occur in the foot and ankle. Soft tissue tumors are more common than bone tumors. Tumors of the foot and ankle are generally benign or nonneoplastic. Patients with suspected malignant lesions should be referred to a specialized bone tumor unit before biopsy.

Bone marrow oedema of the knee

Magnetic resonance (MR) imaging is a frequently performed investigation for disease of the knee. Bone marrow oedema (BME) is a common MR finding with a number of causes including trauma, tumour, infection, inflammatory arthropathies and BME syndromes. This article illustrates the range of MR appearances of BME around the knee and describes secondary signs that allow the reader to determine the cause of disease and to distinguish BME from normal marrow signal changes.

Cytokine synthesis by chondroblastoma: relation to local inflammation

PURPOSE

To investigate cytokine production by chondroblastoma in inducing local inflammation and adjacent-joint arthritis.

METHODS

Immunohistochemical analyses of curetted tissues using anti-human interleukin (IL)-1 beta, IL- 6, IL-8, and tumour necrosis factor (TNF)-alpha were performed for 6 patients with chondroblastoma and 3 patients with giant cell tumour (GCT) of bone. In addition, prostaglandin E2, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-8, and TNF-alpha in the cyst fluid of one of the patients with chondroblastoma and 2 with GCT of bone were measured using immunoassay kits.

RESULTS

More positive staining for IL-1 beta, IL-8, IL- 6, and TNF-alpha was shown in chondroblastoma than GCT of bone samples. Osteoclast-like giant cells in chondroblastomas showed positive staining for IL- 6 only. In addition, concentrations of IL-4, IL-6, and IL-8 in the cyst fluid were higher in the one patient with chondroblastoma than the 2 patients with GCT of bone.

CONCLUSION

Cytokines such as IL-1 beta, IL-8, TNF-alpha, and particularly IL-6 play an important role in local inflammation in patients with chondroblastoma.

Osteoblastoma of the spine with discordant magnetic resonance imaging and computed tomography imaging features in a child

STUDY DESIGN

Case report.

OBJECTIVE

To describe the magnetic resonance imaging (MRI) and computed tomography (CT) findings of spinal osteoblastoma and illustrate how MRI features can be potentially misleading.

SUMMARY OF BACKGROUND DATA

Osteoblastoma is a rare benign tumor of bone that is known to incite a localized inflammatory response. These inflammatory features can simulate malignant behavior on MRI and can lead to misdiagnosis and unnecessarily aggressive resection unless one recognizes the classic benign features on CT. We present a case of osteoblastoma in a child to illustrate this concept.

METHODS

The patient's clinical and radiologic history is discussed with a brief review of the relevant literature.

RESULTS

A 9-year-old girl with back pain receives an MRI of the lumbar spine demonstrating a sacral tumor with potentially malignant features including extensive marrow edema and enhancement. A CT demonstrates a well-circumscribed lesion without lytic changes or malignant bone formation. A benign lesion was favored given the CT features and conservative resection was performed. Final pathologic diagnosis was osteoblastoma.

CONCLUSION

This case illustrates that the MRI findings for osteoblastoma can be misleading and caution should be used when evaluating benign tumors with known inflammatory responses on MRI. CT features seem to more accurately reflect the true nature and extent of the tumor.

Bone marrow oedema associated with benign and malignant bone tumours

Bone marrow oedema is associated with a wide variety of pathological processes including both benign and malignant bone tumours. This imaging finding in relation to intraosseous tumours can aid in providing a more focused differential diagnosis. In this review, we will discuss the MR imaging of bone marrow oedema surrounding intraosseous neoplasms. The different pulse sequences used in differentiating underlying tumour from surrounding oedema are discussed along with the role of dynamic contrast enhanced MRI. Benign lesions commonly associated with bone marrow oedema include osteoid osteoma, osteoblastoma, chondroblastoma and Langerhan's cell histiocytosis. Metastases and malignant primary bone tumours such as osteosarcoma, Ewing's sarcoma and chondrosarcoma may also be surrounded by bone marrow oedema. The imaging findings of these conditions are reviewed and illustrated. Finally, the importance of bone marrow oedema in assessment of post chemotherapeutic response is addressed.

Diagnosing an extra-axial chordoma of the proximal tibia with the help of brachyury, a molecule required for notochordal differentiation

Chordomas are rare malignant bone tumours considered to arise from notochordal remnants that persist in the axial skeleton. Although their morphology can resemble that of a carcinoma, chondrosarcoma or malignant melanoma, the axial location and their well-defined immunophenotype, including expression of cytokeratins (CK7/20/8/18/19) and S100, generally allow the diagnosis to be made with confidence once the possibility is considered. In contrast, making a robust diagnosis of an extra-axial chordoma has been difficult in the absence of specific markers for chordomas. We have recently shown in gene expression microarray and immunohistochemistry studies that brachyury, a transcription factor crucial for notochordal development, is a specific and sensitive maker for chordomas. We now present a case of an intracortical tibial tumour, with detailed report of the imaging, and morphological features consistent with a chordoma, where notochordal differentiation was demonstrated with an antibody to brachyury. The tumour cells were also positive for cytokeratins, including CK19, and S100, CEA, EMA and HMBE1, findings which support the diagnosis of chordoma. Brachyury can be employed as a marker of notochordal differentiation and help identify confidently, for the first time, extra-axial bone and soft tissue chordomas, and tumours which may show focal notochordal differentiation.

MRI of bone marrow oedema associated with focal bone lesions

AIM

To quantify the volume of bone marrow oedema surrounding focal bone lesions and to identify its relevance relative to diagnosis.

METHODS

Three hundred and eighty-eight of 1456 patients included in the orthopaedic oncology database who underwent magnetic resonance imaging (MRI) demonstrated bone marrow oedema and were included in the study. There were 225 males and 163 females, age range 1-87 years (mean 29 years). MRI images were retrospectively reviewed and assessed for the extent of bone marrow oedema. The amount of oedema was graded: grade 1: oedema present but smaller than the lesion size; grade 2: oedema equivalent to the lesion size; grade 3: oedema greater than the lesion size.

RESULTS

There were 190 grade 1 lesions: 56% malignant, 33% benign, 11% non-neoplastic; 74 grade 2 lesions: 19% malignant, 50% benign, 31% non-neoplastic; and 124 grade 3 lesions: 10% malignant, 46% benign, 44% non-neoplastic. There was a significant relationship between oedema grade (i.e., volume of oedema) and final diagnosis (p<0.0005).

CONCLUSION

Bone marrow oedema may be associated with a wide range of focal bony lesions, including malignant, benign and non-neoplastic causes. As the volume of bone marrow oedema increases relative to the size of the underlying lesion, the probability that the underlying lesion is benign is increased.

Imaging and differential diagnosis of primary bone tumors and tumor-like lesions of the spine

Primary bone tumors and tumor-like lesions of the spine and sacrum are rare. A wide variety of benign and malignant lesions can arise in the spine and sacrum. Specific diagnosis is based on the location, matrix appearance and patient's age at time of presentation. In this location CT is often necessary for matrix characterization, particularly, detection of mineralization. MRI can be helpful for further characterization and radiological differential diagnosis. An overview of age distribution and imaging features including pattern for differential diagnosis is presented for the most frequent primary spinal bone tumors and tumor-like lesions.

Subperiosteal aneurysmal bone cyst with associated bone marrow oedema: An unusual appearance

A case of a subperiosteal aneurysmal bone cyst with adjacent bone marrow oedema is presented. Aneurysmal bone cysts have been well documented in the published literature; however, relatively few have been observed in a subperiosteal location, and associated bone marrow oedema in the absence of a demonstrable pathological fracture is a rare finding. Aneursymal bone cyst should be considered in the differential diagnosis of subperiosteal bone lesions and may be associated with bone marrow oedema.

Solid variant of aneurysmal bone cysts in long tubular bones: giant cell reparative granuloma

OBJECTIVE

The purpose of this study was to determine the age distribution, location, and imaging features of histologically proven solid variants of aneurysmal bone cysts in long tubular bones.

MATERIALS AND METHODS

We performed a retrospective review of imaging studies of histologically proven solid aneurysmal bone cysts in long bones between 1961 and 2001. There were 30 cases comprising 29 radiographic, six CT, and eight MR imaging examinations. The lesions were evaluated for bone involved, location within a long bone, matrix, size, soft-tissue mass, and MR imaging characteristics. The imaging findings were correlated with the histologic findings.

RESULTS

The patients were 17 females and 13 males ranging in age from 2 to 58 years (mean, 18 years). The bones involved were the femur (n = 10), the ulna (n = 7), the tibia (n = 7), the humerus (n = 2), the radius (n = 2), and the fibula (n = 2). The lesions were five juxtaarticular, 13 metaphyseal, one diametaphyseal, and 11 diaphyseal. The location was eccentric in 20 cases, of which two were intracortical and two periosteal, and central in 10. Lesion size varied between 1 and 7 cm. Thirty-three percent of lesions were nonaneurysmal. Four lesions were mineralized. A soft-tissue mass was present in four cases. Four lesions showed a permeative-lytic pattern simulating a malignant process. Unusual findings included periosteal reaction and development of a solid aneurysmal bone cyst in a preexisting fracture. MR imaging showed solid elements in all cases and pronounced edema in 50% of cases.

CONCLUSION

Solid aneurysmal bone cyst is a reactive nonneoplastic bone lesion with varied imaging characteristics; one third of lesions are nonaneurysmal.

Myolysis of the erector spinae muscles as the cause of scoliosis in osteoid osteoma of the spine

STUDY DESIGN

A case of an osteoid osteoma at the lower thoracic spine with scoliosis is reported.

OBJECTIVES

To suggest that myolysis of the erector spinae muscles reflected by signal abnormalities on magnetic resonance images causes back pain, protective muscle contraction, and scoliosis.

SUMMARY OF BACKGROUND DATA

Osteoid osteomas of the spine are frequently accompanied by scoliosis. The proposed mechanism of the scoliosis has been explained as a postural adaptation of the spine through predominant muscle spasm on the concave side.

METHODS

The history of the patient and radiologic, magnetic resonance imaging, and histologic findings of the peritumoral area were reviewed.

RESULTS

Magnetic resonance images showed signal abnormalities on muscles surrounding the tumor, and use of gadopentetate dimeglumine resulted in an enhancement. The microscopic examination of the erector spinae muscles that demonstrated high intensities on T2-weighted images showed derangement or destruction of the muscle fibers and replacement of the muscle fibers with fat tissue and infiltrating inflammatory cells.

CONCLUSION

These findings were interpreted as those of myolysis. The suggested mechanism of the induction of scoliosis by the present osteoid osteoma is that the unaffected iliocostalis and quadratus lumborum muscles on the tumor side predominantly contracted over those on the opposite side to decrease the tension of the erector spinae muscles involved in myolysis, thereby producing a functional scoliosis.