The World Health Organization's histologic classification of bone tumors. A commentary on the second edition

Radiographic assessment of incidental bone lesions of the proximal humerus: a prevalence study

BACKGROUND

An increased prevalence of benign lesions has been associated with the increased use of radiological tools in orthopedic practice.

PURPOSE

To investigate the inter-observer reliability of the radiographic detection of lesions on the proximal humerus between different observers.

MATERIAL AND METHODS

X-ray radiological examinations of 17,243 patients were performed by an orthopedic surgeon to assess the presence of proximal humeral bone lesions. After this initial screening, 201 patients with lesions were identified and these 201 scans were assessed by three different physicians: an orthopedic oncologist, an orthopedic surgeon, and a musculoskeletal radiologist. Of the 201 patients with lesions, 80 had magnetic resonance imaging in addition to X-rays and were assessed. The diagnosis of the lesions was determined by each participant according to their radiological appearance to assess inter-observer reliability.

RESULTS

The prevalence of proximal humeral lesions was determined by the orthopedic surgeon to be 1.165% (201 of 17,243 patients). In 201 patients with a lesion, the mean age was 48 ± 17 years (range = 18-91 years). According to the assessments of the orthopedic oncologist, orthopedic surgeon, and musculoskeletal radiologist, the most common bone lesion identified was enostosis, with prevalence percentages of 53.7%, 59.7%, and 64.7%, respectively. A noteworthy consensus exists in the collective diagnosis of bone lesions among the three investigators, demonstrated by a substantial agreement with Fleiss' κ at 0.74 (P < 0.001).

CONCLUSION

There was remarkable agreement between the three investigators on the collective diagnosis of bone lesions. Enostosis was the most common bone lesion at the proximal humerus in our series.

Bifunctional bone substitute materials for bone defect treatment after bone tumor resection

Aggressive benign, malignant and metastatic bone tumors can greatly decrease the quality of patients' lives and even lead to substantial mortality. Several clinical therapeutic strategies have been developed to treat bone tumors, including preoperative chemotherapy, surgical resection of the tumor tissue, and subsequent systemic chemo- or radiotherapy. However, those strategies are associated with inevitable drawbacks, such as severe side effects, substantial local tumor recurrence, and difficult-to-treat bone defects after tumor resection. To overcome these shortcomings and achieve satisfactory clinical outcomes, advanced bifunctional biomaterials which simultaneously promote bone regeneration and combat bone tumor growth are increasingly advocated. These bifunctional bone substitute materials fill bone defects following bone tumor resection and subsequently exert local anticancer effects. Here we describe various types of the most prevalent bone tumors and provide an overview of common treatment options. Subsequently, we review current progress regarding the development of bifunctional bone substitute materials combining osteogenic and anticancer efficacy. To this end, we categorize these biomaterials based on their anticancer mechanism deriving from i) intrinsic biomaterial properties, ii) local drug release of anticancer agents, and iii) oxidative stress-inducing and iv) hyperthermia-inducing biomaterials. Consequently, this review offers researchers, surgeons and oncologists an up-to-date overview of our current knowledge on bone tumors, their treatment options, and design of advanced bifunctional biomaterials with strong potential for clinical application in oncological orthopedics.

Application of Machine Learning for Differentiating Bone Malignancy on Imaging: A Systematic Review

An accurate diagnosis of bone tumours on imaging is crucial for appropriate and successful treatment. The advent of Artificial intelligence (AI) and machine learning methods to characterize and assess bone tumours on various imaging modalities may assist in the diagnostic workflow. The purpose of this review article is to summarise the most recent evidence for AI techniques using imaging for differentiating benign from malignant lesions, the characterization of various malignant bone lesions, and their potential clinical application. A systematic search through electronic databases (PubMed, MEDLINE, Web of Science, and clinicaltrials.gov) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 34 articles were retrieved from the databases and the key findings were compiled and summarised. A total of 34 articles reported the use of AI techniques to distinguish between benign vs. malignant bone lesions, of which 12 (35.3%) focused on radiographs, 12 (35.3%) on MRI, 5 (14.7%) on CT and 5 (14.7%) on PET/CT. The overall reported accuracy, sensitivity, and specificity of AI in distinguishing between benign vs. malignant bone lesions ranges from 0.44–0.99, 0.63–1.00, and 0.73–0.96, respectively, with AUCs of 0.73–0.96. In conclusion, the use of AI to discriminate bone lesions on imaging has achieved a relatively good performance in various imaging modalities, with high sensitivity, specificity, and accuracy for distinguishing between benign vs. malignant lesions in several cohort studies. However, further research is necessary to test the clinical performance of these algorithms before they can be facilitated and integrated into routine clinical practice.

Surgery Has Positive Effects on Spinal Osteosarcoma Prognosis: A Population-Based Database Study

OBJECTIVE

The treatment of osteosarcoma of the spine remains controversial. Our aim was to explore the treatment of patients with spinal osteosarcoma.

METHODS

We analyzed the data from 727 spinal osteosarcoma patients from the Surveillance, Epidemiology, and End Results database from 1973 to 2015. X-tile software was used to find the optimal cutoff values for age and economic income. The Kaplan-Meier estimator method was used to analyze overall survival and cancer-specific survival. Univariate and multivariate Cox analyses were used to identify the independent prognostic factors. Propensity score matching was used to reduce the possibility of selection bias. A logistic regression model was used to clarify the relevant factors affecting a patient's decision to undergo surgery.

RESULTS

Among 727 eligible spinal osteosarcoma patients, 370 (50.9%) had undergone surgery and 357 (49.1%) had not undergone surgery. Significant differences were found in the effects of patient age at diagnosis, Surveillance, Epidemiology, and End Results historical stage, and tumor grade on the patients' decision to undergo surgery (P < 0.05). Surgery was an independent prognostic factor for overall survival and cancer-specific survival of patients with spinal osteosarcoma. The same results were found after 1:1 propensity score matching. The surgery group had more favorable survival compared with the nonsurgery group.

CONCLUSIONS

Surgery can provide survival benefits for patients with osteosarcoma of the spine. The patients with spinal osteosarcoma who had undergone surgery experienced favorable survival benefits. Thus, surgery can be a suitable treatment for patients with spinal osteosarcoma.

Osteoblastoma and Osteoid Osteoma of the Mandible: Review of the Literature and Report of Two Cases

Osteoblastoma and osteoid osteoma are rare benign neoplasms of the jaws. We reviewed current literature surrounding the ongoing debate over similarities and differences of osteoblastoma and osteoid osteoma and present two cases. Both cases are well-demarcated mixed radiodensity mandibular lesions with histological features of osteoblastoma. They exhibit, however, distinctly unique and contrasting clinical and imaging characteristics suggesting that the first case is osteoblastoma and the second is osteoid osteoma. The first case of a 37-year-old male presents with a large, expansile lesion at posterior mandible, surrounded by a thick sclerotic band. Unusual features include significant buccal/lingual expansion, extensive new bone apposition, and soft tissue edema in the masseter muscle. This is in contrast to the second case of a much smaller lesion in a 17-year-old male with history of recent third molar extraction in the left posterior mandible. In this case, CT imaging revealed a circular, nonexpansile lesion with a sclerotic border surrounded by a radiolucent rim. Both patients underwent surgical excision of the lesion with extraction of the adjacent tooth. We discuss herein the distinct clinical and imaging features.

Zygomatic Arch Parosteal Osteosarcoma in Dogs and a Cat

Parosteal osteosarcoma is a rare, slow-growing tumor most commonly arising from the surface of long bones. Tissue or histological sections from 5 dogs and 1 cat with zygomatic arch masses were examined. Clinical presentations varied from chronic sneezing to facial swelling. Imaging consistently demonstrated osseous proliferation in the area of the zygomatic arch. Histologically, the masses were characterized by well-differentiated fibro-osseous and chondroid components that radiated outward from the periosteum of the zygomatic bone. Cellular atypia and mitotic figures were uncommon. Parosteal osteosarcomas have previously been reported in the skulls of dogs and cats, but only 1 has been reported on the zygomatic arch. Initially, these tumors are of low histologic low grade, but with time, they can show more aggressive behavior and invade the underlying bone.

Histopathological pattern of primary bone tumours and tumour-like lesions in Ile-Ife, Nigeria

INTRODUCTION

Bone tumours are relatively rare in comparison with neoplasms in other parts of the body. Previous studies have noted higher frequencies of these tumours in young adults with potentially devastating consequences.

METHODS

This study aimed to demonstrate the histopathological pattern of primary bone tumours and tumour-like lesions in Ile-Ife, Nigeria with emphasis on relative frequencies and distribution according to age, sex and anatomical location. A 13 year (1991-2003) retrospective study was carried out on 100 cases of primary bone tumours and tumour-like lesions. Records were retrieved from the surgical registers of the Histopathology Department, Qbafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. Original histopathological slides were retrieved for examination and when they were unavailable, the paraffin blocks were searched out and new slides were made.

RESULTS

A total of 100 cases met the inclusion criteria for this study accounting for 1.55% of the 6,464 cases of all neoplasms seen within this period. Of the 100 cases, 50 were malignant (50%), 28 were benign (28%) and 22 had tumour-like lesions (22%). The male to female ratio was 1.3:1 and the most common benign and malignant tumours were osteochondroma and osteosarcoma respectively. The femur was the most frequently involved bone in primary malignant lesions (24%) followed by the pelvis and the maxilla (14% each).

CONCLUSION

The age, sex and morphological distribution of benign and malignant bone tumours is similar to earlier reports in other African and international journals. Tumour-like lesions occur more frequently in females than in males. The femur is the most favourable site for malignant primary bone tumours and the jaw bones for tumour-like lesions.

ALCAM+ stromal cells: role in giant cell tumor of bone progression

Giant cell tumor of bone(GCTB) is a special benign tumor with variable aggressiveness and recurrence rate. Increasing evidences suggest that a subset of cells called cancer stem cells (CSCs) are present as cancer-initiating cells in a range of malignant tumors. However, the role of CSCs in benign tumor such as GCTB remains unknown, and the connection between the presence of CSCs and biological characteristics of GCTB is unclear. To investigate this issue, we screened a panel of markers of normal stem cells and CSCs and found ALCAM+ stromal cells possessed characteristics of stem-like cells. Subsequently a series of experiments such cell proliferation, migration and invasion assays were performed to investigate the biological characteristics of ALCAM+ stromal cells in vivo and in vitro. The clinical significance of ALCAM expression were further evaluated using Kaplan-Meier analyses. The ALCAM+ GCTB cells showed the stem cell properties of self renewal and had the capacity to differentiate in vitro. The ALCAM+ GCTB cells showed increased resistance for chemotherapy- or radiation-induced cell death. ALCAM knockdown reduced stem/progenitor characteristics in GCTB Cells. Furthermore, ALCAM expression was associated with outcome in GCTB patients. Our work demonstrates for the first time ALCAM+ tumorigenic sub-population within stromal GCTB cells and may represent a potential therapeutic target in aggressive and recurrent GCTBs.

A new therapeutic proposal for inoperable osteosarcoma: Photodynamic therapy

BACKGROUND

Osteosarcoma, a malignant tumor characterized by bone or osteoid formation, is the second most common primary bone neoplasm. Clinical symptoms include local and surrounding pain, unrelieved by rest or anesthesia. Osteosarcoma has a poor chemotherapeutic response with prognosis dependent on complete tumor excision. Therefore, for inoperable osteosarcoma new therapeutic strategies are needed. The present study aimed to develop murine models of cranial and vertebral osteosarcoma that facilitate simple clinical monitoring and real-time imaging to evaluate the outcome of photodynamic therapy based on a previously developed photosensitizer.

METHODS

Balb/c nude mice were divided into two groups: the cranial and vertebral osteosarcoma groups. Each group was further subdivided into the photodynamic therapy-treated and untreated groups. Images were obtained by scintigraphy with ^99mTc-MIBI and radiography. Tumor growth, necrotic area, osteoid matrix area, and inflammatory infiltration were analyzed.

RESULTS

Cranial and vertebral tumors could be macroscopically observed and measured. Radiographic and scintigraphic images showed tumor cells present at the inoculation sites. After photodynamic therapy, scintigraphy showed lower tumoral radiopharmaceutical uptake, which correlated histologically with increased necrosis. Osteoid matrix volume increased, and tumor size decreased in all photodynamic therapy-treated animals.

CONCLUSION

Cranial and vertebral osteosarcoma models in athymic mice are feasible and facilitate in vivo monitoring for the development of new therapies. Photodynamic therapy is a potential antitumoral treatment for surgically inoperable osteosarcoma.

SPAG9 is overexpressed in osteosarcoma, and regulates cell proliferation and invasion through regulation of JunD

Sperm-associated antigen 9 (SPAG9) is a recently characterized oncoprotein that is considered to be involved in several forms of malignant tumor. However, its biological function and expression pattern in human osteosarcoma have not yet been elucidated. In the present study, SPAG9 expression was analyzed in 58 cases of human osteosarcoma by immunohistochemistry. The results demonstrated that SPAG9 was overexpressed in 63.8% (37/58) of osteosarcoma tissues, while normal bone tissues exhibited negative SPAG9 expression. SPAG9 small interfering RNA was employed in the U2OS cell line, which has high endogenous expression, and SPAG9 transfection was performed in the MG63 cell line, which has low endogenous expression. MTT and Matrigel invasion assays demonstrated that SPAG-9-knockdown significantly reduced U2OS cell invasion and proliferation, while SPAG9 transfection enhanced MG63 cell proliferation and invasion. Furthermore, it was observed that SPAG9 positively regulated cyclin D1, phosphorylated-c-Jun NH2-terminal kinase (JNK) and JunD expression. Treatment with the JNK inhibitor, SP600125, abolished the upregulatory effect of SPAG9 on JunD. Taken together, the present study identified SPAG9 as a critical oncoprotein involved in osteosarcoma proliferation and invasion, possibly functioning through JNK-JunD signaling.

Pathological fracture of the patella due to an atypical located aneurysmal bone cyst: verification by means of ultrasound-guided biopsy

INTRODUCTION

We report on a rare case of an atypical located aneurysmal bone cyst (ABC) in the patella presenting with pathological fracture after trauma.

MATERIALS AND METHODS

Using all available diagnostic modalities and by means of ultrasound-guided core-needle biopsy an unclear and suspected pathological fractured cystic bone lesion in the patella of a young man could be further clarified.

RESULTS

The acquired images suggested the diagnosis of a pathological fractured aneurysmal bone cyst after mild trauma. However, due to the extraordinary location and clinical presentation the diagnosis was secured by means of ultrasound-guided biopsy through a small cortical gap.

CONCLUSION

As shown in this rare case of an atypical aneurysmal bone cyst of the patella, the quite seldom but sometimes possible ultrasound-guided biopsy of intraosseous lesions can help to achieve the diagnostic clarification and should also be taken into account as a non-standard procedure.

Orbital ossifying fibroma: A case report

CLINICAL CASE

The case concerns a 34 year-old man, who presented with pain in the medial canthus in his left eye, with proptosis and diplopia. The examination showed exophthalmus and a palpable mass at the inner canthus. The computed tomography revealed a lesion, which was confirmed by biopsy to be a ossifying fibroma.

DISCUSSION

Ossifying fibroma is a benign fibro-osseous lesion that mostly affects the jaw. Clinical presentation and complications vary according to its location. Clinical examination, imaging, and histopathology are essential for definitive diagnosis. Surgical treatment is multidisciplinary and long-term follow up is needed.

Desmoplastic Fibroma of the Pediatric Cranium: An Aggressive Skull Tumor with Local Recurrence

Cranial desmoplastic fibroma (DF) is extremely rare and only 20 cases, including only 7 pediatric cases, have been reported previously. We describe the first case of a child with cranial DF that increased in size over a short-term and recurred after resection. The aim of this case report was to discuss the clinical, radiological, and histological characteristics and optimal treatment for this rare and aggressive skull tumor.

A recurrent giant cell tumor of bone treated with denosumab

Although the giant cell tumor of bone is generally classified as a benign tumor it can rarely metastasize and has a potential risk of local recurrence. We want to report about a female patient who suffered from a recurrence of a giant cell tumor of bone after the implantation of a total endoprosthesis of the knee joint. We have treated her with denosumab, which is a receptor activator of nuclear factor kappa-B ligand inhibitor. In this case report we want to present a new option to treat this kind of neoplasm.

[Osteosarcoma: reliability and quality of the information in the internet]

The World Wide Web has grown during the last years to a considerable source of medical information for experts as well as for laymen and patients. The quality of this information is subjected to some limitation linked with the structure of the Internet and the management of Internet pages. The cross- sectional study presented evaluates and compares quality and reliability of information with respect of osteosarcoma in the most common German-language Internet pages for medical information. As both, one of the most common primary malignant bone tumors and its peak of incidence at the age of childhood and youth, osteosarcoma is considered of significant importance in orthopedic oncology.

Diaphyseal osteosarcoma with varying histomorphologic patterns

Osteosarcoma is the most common primary malignant tumor of the skeleton involving predominantly metaphysis of the long bones. Diaphyseal osteosarcoma is a rare form, which accounts for approximately 10% of all cases of osteosarcomas. Osteosarcoma contains a family of lesions with considerable diversity in histologic features and grade. We present a case of a 29-year-old male with diaphyseal osteosarcoma of the left tibia, who presented with pain and swelling over middle one-third of the left leg. The biopsy of the lesion revealed varied histomorphologic features in a small tissue studied. This prompted us to report the various histologic patterns of osteosarcoma.

Osteosarcoma of the mandible masquerading as a dental abscess: report of a case

An aggressive and fatal case of osteosarcoma of the mandible in a 19-year-old female is reported. Six weeks after the clinical appearance of the swelling, the patient died. This paper is unique in that the age of occurrence and the biologic behavior of the tumor were not consistent with the reported literature. The case report is followed by a brief review of osteosarcoma of the jaw with a note on its clinical presentation, diverse radiologic appearance, varied histopathologic picture, and prognosis.

A suspected malignancy in osteolytic bone tumour of the thumb

A 75-year-old male patient was referred to our institution owing to a painful and gradually developing lesion of the thumb with suspicious malignancy. The patient was suffering from a swollen, red, tender left thumb for 3 months. An old scar at the finger pulp could be traced from an old minor trauma. The x-ray revealed an osteolytic lesion in the terminal phalanx of the non-dominant hand that raised concerns of malignancy. Additional investigations such as ultrasound, CT-scan and MRI have been performed to get better insight to the lesion. After performing a biopsy, no malignant cells were found. Owing to the local destroying effect of the lesion and the clinical signs of the patient, the lesion was excised in total. The histopathological evaluation confirmed the tumour as a rare intraosseous epidermoid cyst. A bone graft after resection was not needed. The postoperative follow-up of the patient was uneventful.

Analysis of miRNA-gene expression-genomic profiles reveals complex mechanisms of microRNA deregulation in osteosarcoma

Osteosarcoma is an aggressive sarcoma of the bone characterized by a high level of genetic instability and recurrent DNA deletions and amplifications. This study assesses whether deregulation of microRNA (miRNA) expression is a post-transcriptional mechanism leading to gene expression changes in osteosarcoma. miRNA expression profiling was performed for 723 human miRNAs in 7 osteosarcoma tumors, and 38 miRNAs differentially expressed ≥10-fold (28 under- and 10 overexpressed) were identified. In most cases, observed changes in miRNA expression were DNA copy number-correlated. However, various mechanisms of alteration, including positional and/or epigenetic modifications, may have contributed to the expression change of 23 closely linked miRNAs in cytoband 14q32. To develop a comprehensive molecular genetic map of osteosarcoma, the miRNA profiles were integrated with previously published array comparative genomic hybridization DNA imbalance and mRNA gene expression profiles from a set of partially overlapping osteosarcoma tumor samples. Many of the predicted gene targets of differentially expressed miRNA are involved in intracellular signaling pathways important in osteosarcoma, including Notch, RAS/p21, MAPK, Wnt, and the Jun/FOS pathways. By integrating data on copy number variation with mRNA and miRNA expression profiles, we identified osteosarcoma-associated gene expression changes that are DNA copy number-correlated, DNA copy number-independent, mRNA-driven, and/or modulated by miRNA expression. These data collectively suggest that miRNAs provide a novel post-transcriptional mechanism for fine-tuning the expression of specific genes and pathways relevant to osteosarcoma. Thus, the miRNA identified in this manner may provide a starting point for experimentally modulating therapeutically relevant pathways in this tumor.

Recurrent giant cell reparative granuloma of the skull base and the paranasal sinuses presenting with acute one-sided blindness

The etiology, pathogenesis, histopathologic diagnosis, prognosis, and treatment of giant cell reparative granulomas of the skull are controversial. We report a 14-year-old girl with an advanced recurrent giant cell reparative granuloma of the skull base and paranasal sinuses whose only clinical manifestation was a loss of vision. After undergoing endovascular catheter embolization, the patient underwent repeated surgical resections of the mass via a combined frontobasal and modified infratemporal approach followed by radiation therapy. Histopathologic examination confirmed the diagnosis of giant cell reparative granuloma. A traumatic event in the patient's history-a fossa canina abscess followed by tooth extraction 14 months before admission-supports the theory of a reactive reparative process as a pathogenetic mechanism for this disease. Histopathologic criteria and clinical aggressiveness must be considered to achieve adequate treatment of giant cell lesions of the skull.

IS THERE ANY DIFFERENCE IN THE PROGNOSIS FOR PATIENTS WITH PRIMARY OSTEOSARCOMA WITH A POOR RESPONSE TO NEOADJUVANT CHEMOTHERAPY BETWEEN HUVOS GRADES I AND II?

Would there be any difference in the prognosis for patients who presented, for example, 8% or 88% tumor necrosis induced by chemotherapy, even though both individuals were considered to be poor responders? The aim of this study was to compare the prognoses for different histological grades (Huvos grade I versus grade II), consequent to chemotherapy, among patients with primary osteosarcoma that was not metastatic at diagnosis.

METHODS

Twenty-four patients admitted to a referral center between 2000 and 2004 were selected for the study. The accumulated chances of survival were calculated using the Kaplan-Meier technique. Huvos grades I and II for necrosis consequent to chemotherapy were evaluated as variables in order to determine their prognostic value, in relation to local recurrence-free survival, metastasis-free survival and overall survival, using the log-rank test.

RESULTS

Comparing Huvos grades I and II, the following P values for survival were attained: local recurrence-free survival (P = 0.731), metastasis-free survival (P = 0.596) and overall survival (P = 0.669).

CONCLUSION

In this series, Huvos grades I and II did not have any comparative prognostic value and had similar behavior.

Juxtacortical osteosarcoma of mandible

This article presents a case of juxtacortical (paraosteal) osteosarcoma in a 43-year-old female, which is rare malignant mesenchymal tumor. As per the literature, it accounts for less than 4% of all osteosarcomas. Due to its rare variety, this tumor can cause diagnostic dilemma and clinicians should be aware of it. Due to its clinical picture, it can be confused with peripheral fibro-osseous lesions. Success rate of treatment are good if the tumor is detected early and resected with wide margins giving a negligible chance for recurrence.

Biphasic bone substitute and fibrin sealant for treatment of benign bone tumours and tumour-like lesions

PURPOSE

Bone defects resulting from tumour resection or curettage are most commonly reconstructed with autologous bone graft which is associated with limited availability and donor site morbidity. Recent research has focussed on synthetic biomaterials as bone graft substitutes. The aim of this study was to assess the safety and efficiency of a bone substitute as an alternative for autologous bone in the treatment of benign bone tumours and tumour-like lesions.

METHODS

In the present study, a biphasic ceramic (60% HA and 40% β-TCP) combined with a fibrin sealant was used to reconstruct defects in 51 patients after curettage of benign bone tumours or tumour-like lesions. Patient age ranged from eight to 68 years (mean 29.7), defect size from 2 cm(3) to 35 cm(3) (mean 12.1), and time of follow-up from one to 56 months (mean 22.7).

RESULTS

Radiologic analysis showed complete bony defect consolidation in 50 of 51 patients after up to 56 months. No postoperative fractures were observed. Revision surgery had to be performed in one case. Histological analysis showed new bone formation and good biocompatibility and osseointegration of the implanted material.

CONCLUSION

In summary, the biphasic ceramic in combination with fibrin sealant was proven an effective alternative to autologous bone grafts eliminating the risk of donor site morbidity for the patient.

Advances in the identification of molecular markers for bone neoplasia

IMPORTANCE OF THE FIELD

Bone tumors represent a heterogeneous and poorly understood group of neoplasms affecting patients of all ages. This review is intended to highlight recent advances in the identification of diagnostically relevant molecular biomarkers.

AREAS COVERED IN THIS REVIEW

This review offers a summary of basic techniques in molecular pathology. In the case of primary bone tumors with diagnostically applicable molecular markers, an overview of the tumor is provided incorporating the germane background and advances in the identification of molecular markers.

WHAT THE READER WILL GAIN

The reader will gain an understanding of the techniques governing the discovery of biomarkers, and their applicability in diagnostic bone pathology.

TAKE HOME MESSAGE

Molecular analysis has identified key diagnostic biomarkers in only a small proportion of bone tumors. Many of these findings owe their existence to earlier karyotype-based cytogenetic studies. In cases where characteristic cytogenetic findings are absent, there remains a tremendous need to interrogate rigorously these lesions using emerging techniques such as whole genome sequencing. It is assumed that with a more precise understanding of the tumor genetic code, more accurate diagnostic, prognostic and therapeutic markers will emerge.

Imaging of superficial and deep fibromatosis

The purpose of this paper was to illustrate the role of diagnostic imaging in superficial and deep fibromatosis through a review of the use of different imaging modalities, including radiography, ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), angiography and scintigraphy. In particular, in agreement with published data, it emphasises the crucial role of MRI as the primary modality providing the information needed for management decisions, preoperative planning and follow-up of these lesions.

Recurrent RECQL4 imbalance and increased gene expression levels are associated with structural chromosomal instability in sporadic osteosarcoma

Osteosarcoma (OS) is an aggressive bone tumor with complex abnormal karyotypes and a highly unstable genome, exhibiting both numerical- and structural-chromosomal instability (N- and S-CIN). Chromosomal rearrangements and genomic imbalances affecting 8q24 are frequent in OS. RECQL4 gene maps to this cytoband and encodes a putative helicase involved in the fidelity of DNA replication and repair. This protective genomic function of the protein is relevant because often patients with Rothmund-Thomson syndrome have constitutional mutations of RECQL4 and carry a very high risk of developing OS. To determine the relative level of expression of RECQL4 in OS, 18 sporadic tumors were studied by reverse transcription-polymerase chain reaction. All tumors overexpressed RECQL4 in comparison to control osteoblasts, and fluorescence in situ hybridization analysis of tumor DNA showed that expression levels were strongly copy number-dependent. Relative N- and S-CIN levels were determined by classifying copy number transitions within array comparative genomic hybridization profiles and by enumerating the frequency of break-apart fluorescence in situ hybridization within 8q24 using region-specific and control probes. Although there was no evidence that disruption of 8q24 in OS led to an elevated expression of RECQL4, there was a marked association between increased overall levels of S-CIN, determined by copy number transition frequency and higher levels of RECQL4.

Impaired bone development and increased mesenchymal progenitor cells in calvaria of RB1-/- mice

We have previously shown that the retinoblastoma protein (pRb) can activate expression of Runx2-dependent, bone-specific genes in cultured cells. We now show that pRb also plays a role early in osteogenesis, and that in primary RB1(-/-) calvarial cells there is an increased osteoprogenitor pool. To understand pRb's function in vivo, we generated a conditional RB1-KO mouse in which pRb expression is efficiently extinguished in osteoblasts. These animals display an apparent developmental defect in bones, most strikingly in the calvaria. Cultured RB1(-/-) calvarial osteoblasts fail to cease proliferation upon reaching confluence or following differentiation. Re-plating assays of primary RB1(-/-) calvarial cells after differentiation showed a clear adipogenic ability with increased multipotency. RB1(-/-) osteoblasts display a severe reduction in levels of mRNAs expressed late in differentiation. In this study, we present strong evidence that pRb has multiple regulatory roles in osteogenesis. Furthermore, in the absence of RB1(-/-) there is a larger pool of multipotent cells compared with the WT counterpart. This increased pool of osteoprogenitor cells may be susceptible to additional transforming events leading to osteosarcoma, and is therefore key to understanding RB1 as a target in malignancy.

Expression of c-kit Protein and Mutational Status of the c-kit Gene in Osteosarcoma and Their Clinicopathological Significance

We examined c-kit protein expression and mutations of the c-kit gene in 40 human osteosarcoma samples to their relationship with clinicopathology and prognosis of the disease. The expression of c-kit protein was evaluated by immunohistochemistry and single-strand conformational polymorphism was performed to evaluate c-kit gene mutations in exons 11 and 17. Expression of c-kit protein occurred in 25 (62.5%) osteosarcoma samples. Patients with osteosarcomas with higher c-kit protein expression levels were significantly more likely to experience local disease recurrence and had a significantly lower survival time than patients with lower c-kit expression. We found no evidence of mutations in exons 11 or 17. This study suggests that c-kit protein expression might serve as a prognostic marker for osteosarcoma, however exons 11 and 17 might not be suitable targets for osteosarcoma treatments based on suppression of c-kit tyrosine kinase activity.

Osteosarcoma (osteogenic sarcoma)

Osteosarcoma is a primary malignant tumour of the skeleton characterised by the direct formation of immature bone or osteoid tissue by the tumour cells. The classic osteosarcoma is a rare (0.2% of all malignant tumours) highly malignant tumour, with an estimated incidence of 3 cases/million population/year. Osteosarcoma arises predominantly in the long bones and rarely in the soft tissues. The age at presentation ranges from 10 to 25 years of age. Plain radiographs, computed tomography, magnetic resonance imaging, angiography and dynamic bone scintigraphy are used for diagnosis, evaluation the extent of tumour involvement and decision of the type of operation and, if necessary, the type of reconstruction. Years ago, all patients with osteosarcoma were treated by amputation but the cure rate was under 10% and almost all patients died within a year from diagnosis. Today, for localised osteosarcoma at onset (80% of cases) treated in specialized bone tumour centres with pre- and postoperative chemotherapy associated with surgery, the percentage of patients cured varies between 60% and 70%. Surgery is conservative (limb salvage) in more than 90% of patients. Prognosis is more severe (cure rate about 30%) for tumours located in the axial skeleton and in patients with metastasis at onset.

Recommendations for the reporting of bone tumors

The diagnosis of a bone tumor is often an arduous task, even for the most experienced orthopedic pathologist. As a starting point, the classification of bone tumors is based on a histogenetic perspective encompassing the type of matrix produced (or not produced) by the tumor. In general, the surgical pathology report should include data pertinent to the treatment and prognostication of an individual patient, and the report should be delivered to the clinician in a clear, concise fashion. Reporting of most bone tumors is similar and includes such information as the type of surgery done, anatomic site, histological type and grade of the tumor (if applicable), and the adequacy of surgical margins. Special emphasis is needed for those tumors with distinct and well-established prognostic and therapeutic features such as osteosarcoma and Ewing's sarcoma/peripheral neuroectodermal tumor. Our recommendation emphasizes a standardized protocol for these sarcomas, especially in light of evidence that postchemotherapeutic tumor necrosis is of prognostic significance. It is also important to note that radiographic imaging plays a very important, often critical, role in allowing the pathologist the opportunity to reach the best final diagnosis. This is especially true when a malignant interpretation is contemplated and in subtyping lesions. We recommend close collaboration between musculoskeletal radiologists, clinicians, and pathologists when dealing with complicated neoplasms of bone.

Neuroendocrine-immune surveillance of osteosarcoma: emerging hypothesis

Osteosarcoma is a bone-forming cancer predominantly found in children and adolescents more often than in adults. Osteosarcoma of the gnathic apparatus is relatively rare in the young population, and this condition becomes a concern of clinical dentists for predominantly the middle-aged and aging patient groups. Osteosarcomas are invaded by lymphocytes, which exhibit signs of activation. The immune processes that are engaged within the malignant bone matrix involve the production of cytokines, which regulate the process of apoptotic programmed cell death. This paper discusses the mechanisms by which apoptosis of osteosarcoma cells is modulated by the neuroendocrine-immune system, and potential physiological implications.

Osteofibrous dysplasia of the ulna

We experienced two patients with osteofibrous dysplasia of the ulna. Both of them showed typical radiographic findings of osteofibrous dysplasia, except for location. One patient underwent surgery at the age of 15 years to confirm the diagnosis histologically. Although the tumor recurred 5 months after the surgery, expansion of the lesion seemed to cease at the age of 25 years. In the other patient, the natural course was observed. The tumor showed a tendency toward spontaneous regression at the age of 11 years. Therefore, the nature of osteofibrous dysplasia in the ulna seems to be the same as that in the tibia and fibula. Surgery must be delayed for as long as possible in osteofibrous dysplasia of the ulna, as well as that of the tibia and fibula.

Osteosarcoma of the jaws: a 30-year retrospective review

OBJECTIVE

This article reviews osteosarcomas of the jaws referred to the Department of Oral Pathology, Eastman Dental Institute, for histologic diagnosis during the 30 years from 1968 to 1998, to compare the clinical behavior of the tumors, to assess how they differ from the reported characteristics of tumors from other sites, and to report on observations of clinical and diagnostic significance.

STUDY DESIGN

The clinical, radiographic, and histopathologic records of 25 patients were obtained for retrospective review. Supportive and follow-up clinical and histopathologic material was obtained from the referring clinicians.

RESULTS

The mean age of presentation of the primary lesions was 36. 9 years (range, 10-87 years) with a slight female predilection. The most common presenting features were swelling, pain, ulceration, or a neurologic deficit. The radiographic appearance of the lesions was mixed with areas of radiopacity and radiolucency. Histologically, the lesions ranged from those dominated by immature bony trabeculae separated by a cytologically bland stroma to high-grade, cellular lesions with regions of marked atypia and mitotic activity. Most had areas of chondroid formation, in addition to neoplastic osteoid. The main complication was local recurrence. Metastasis was rare and occurred as a solitary process or at a late stage in the disease progression. This was in contrast to lesions metastatic to the jaws, which were higher grade in appearance and had metastasized widely, early in the disease process. Primary osteosarcoma occurring in patients with a history of radiotherapy was typically more aggressive.

CONCLUSION

Primary osteosarcomas of the jaws are a group of lesions distinct from those occurring in the long bones. Osteosarcomas of the jaw arising in a former radiation field may be a discrete group of lesions with a more aggressive behavior pattern.

Pediatric bone tumors

Although osteosarcoma and Ewing's sarcoma are quite rare, they are the only primary skeletal malignancies that occur with any regularity in children. The evaluation, diagnosis, and management of skeletal neoplasia are reviewed using these two diseases as the focus of discussion. Radiographic imaging, biopsy approaches, diagnostic considerations, and therapeutic management are explained. Demographics and pathophysiology of osteosarcoma and Ewing's sarcoma are explored in more depth.

A giant cell tumor of the sacrum or a soft tissue giant cell tumor? A case report

STUDY DESIGN

A case report.

OBJECTIVE

Giant cell tumors are rare primary bone tumors. Generally, these tumors are expanding osteolytic lesions, but soft tissue giant cell tumors can occur. This is a case report of an unusual incidence of a giant cell tumor within the spinal sacral canal, in which there was no involvement of the surrounding bone or ligament structures and that was signaled by radicular pain. The pathologic course of the tumor is described.

SUMMARY OF BACKGROUND DATA

A 24-year-old woman had monoradicular pain in the right leg in the region of S2. Neuroradiologic examination showed a mass within the sacral spinal canal compromising the right S2 root, with no sign of bone involvement.

METHODS

A sacral laminectomy was performed. A tumor was located entirely intraspinally and extradurally and was removed completely. A giant cell tumor was identified in histologic examination.

RESULT

The patient recovered completely. No local regrowth or metastasis occurred during a 20-month follow-up.

CONCLUSION

The treatment of choice in giant cell tumors is complete surgical resection. Radiotherapy is recommended in cases of subtotal resection. Careful follow-up is warranted, because recurrence and metastasis are not uncommon.

Collagenase-3 (MMP-13) expression in chondrosarcoma cells and its regulation by basic fibroblast growth factor

Human collagenase-3 (MMP-13) is a member of the matrix metalloproteinase family of enzymes that was originally identified in breast carcinomas and subsequently detected during fetal ossification and in arthritic processes. In this work, we have found that collagenase-3 is produced by HCS-2/8 human chondrosarcoma cells. An analysis of the ability of different cytokines and growth factors to induce the expression of collagenase-3 in these cells revealed that basic fibroblast growth factor (bFGF or FGF-2) strongly up-regulated the expression of this gene. By contrast, other factors, including interleukin-1beta and transforming growth factor-beta, previously found to induce collagenase-3 expression in other cell types, did not exhibit any effect on the expression of this gene in chondrosarcoma cells. Further analysis of the bFGF-induced expression of collagenase-3 in human chondrosarcoma cells revealed that its effect was time and dose dependent, but independent of the de novo synthesis of proteins. Western blot analysis revealed that the up-regulatory effect of bFGF on collagenase-3 was also reflected at the protein level as demonstrated by the increase of immunoreactive protein in the conditioned medium of HCS-2/8 cells treated with bFGF. Immunohistochemical analysis of the presence of collagenase-3 in a series of 8 benign and 16 malignant cartilage-forming neoplasms revealed that all analyzed malignant chondrosarcomas stained positively for collagenase-3, whereas only 2 of 8 benign lesions produced this protease. In addition, the finding that bFGF was detected in all analyzed chondrosarcomas, together with the above in vitro studies on HCS-2/8 cells, suggest that this growth factor may be an in vivo modulator of collagenase-3 expression in these malignant tumors. These results extend the pattern of tumor types with ability to produce this matrix metalloproteinase and suggest that collagenase-3 upregulation may contribute to the progression of human chondrosarcomas.