Premalignant conditions of bone

Giant cell tumor of bone and secondary osteoarthritis

Giant cell tumor of bone is a commonly encountered aggressive epiphyseal bone tumor, most often treated surgically. The natural history and presentation are classically described but the histopathology is poorly understood. Intralesional curettage is the mainstay of treatment, but there is significant variation in the use of adjuvant and cavity filling modalities. No gold standard has been agreed upon for treatment, and a variety of techniques are currently in use. Given its location, secondary osteoarthritis is a known long-term complication. This review examines the natural history of giant cell tumors, treatment options and complications, and subsequent development of osteoarthritis. Arthroplasty is usually indicated for secondary osteoarthritis although data is limited on its efficacy. Further directions will likely center on improved pharmacological treatments as well as improved arthroplasty techniques.

Analysis of foot-originating malignant bone tumors: Epidemiology, characteristics, and survival outcomes

BACKGROUND

The study examines the characteristics and outcomes of foot-originating malignant bone tumors via Surveillance Epidemiology and End Results (SEER) database analysis.

METHODS

A retrospective review of 14,695 malignant bone tumor cases from 2000 to 2019 was conducted.

RESULTS

Of the eligible cases, 147 (2.3 %) were foot-origin tumors, typically smaller and more commonly treated with surgery than those in other locations. These tumors were more frequently treated with surgical resection, with a higher proportion undergoing amputation. In contrast, foot-origin tumors were less often managed with chemotherapy and radiation. Foot-origin tumors exhibited higher survival rates compared to non-foot-origin tumors as shown in univariate analysis, although multivariate analysis did not reflect significant differences.

CONCLUSION

Foot-originating malignant bone tumors tend to be smaller and are frequently surgically treated, correlating with favorable survival outcomes. These findings point to early detection as a potential factor in the improved survival rates, not necessarily the tumor's origin.

[Giant cell tumor of bone-an update]

In the past few years, numerous new insights have been gained in the field of giant cell tumor of bone (GCTB). On the one hand, the detection of the highly characteristic histone mutation in the H3F3A gene in GCTB is becoming increasingly important in diagnostics in differentiating GCTB from other giant cell-rich lesions of bone as well as for defining rare variants of GCTB without osteoclastic giant cells. On the other hand, the effects of the H3F3A mutation were shown to have an impact on the epigenetic profile of tumor-driving stromal cells, providing new insights into tumorigenesis of GCTB.

Establishment of Iran Musculoskeletal Tumor Registry: A Study Protocol and Lessons Learned from Implementation and the Pilot Phase

Background

The number of available musculoskeletal tumor registries is relatively small. We developed a registry system focused on the clinical aspects of musculoskeletal tumors to improve quality of care indexes through the development of updated national protocols. In this study, we describe our protocol, challenges, and the data collected during the implementation of the registry system in a single-specialty orthopedic center in Iran.

Methods

Three main malignant bone tumors, including osteosarcoma, Ewing sarcoma, and chondrosarcoma, were included in the registry. After establishing a steering committee, we defined the minimum data set based on a literature review and suggestions from an expert panel. Accordingly, the data collection forms and the web-based software were developed. The collected information was categorized into 9 classes, including demographics, socioeconomic data, signs and symptoms, past medical history, family history, laboratory tests, tumor characteristics, primary treatment, and follow-up. Data collection was performed both retrospectively and prospectively.

Results

Until September 21, 2022, a total of 71 patients were registered (21 patients prospectively and 50 patients retrospectively) and consisted of 36 (50.7%) cases of osteosarcoma, 13 (18.3%) cases of Ewing sarcoma, and 22 (31%) cases of chondrosarcoma. The implementation of the registry demonstrated promising data regarding the tumor characteristics, delay patterns, and socioeconomic status of the patients.

Conclusion

The main lessons learned were to develop a monitoring system to make sure that the new staff is adequately trained for the registration process as well as avoid the inclusion of time-consuming useless data in the minimum data set.

Injectable Synthetic Beta-Tricalcium Phosphate/Calcium Sulfate (GeneX) for the Management of Contained Defects Following Curettage of Benign Bone Tumours

Benign and low-grade malignant bone tumours are often treated with curettage and filling of the resultant defect using any of a number of materials, including autologous bone grafts, allografts, or synthetic materials. The objective of this study was to report our experience using a synthetic bone graft substitute in these patients. Ten consecutive cases (four males, six females; mean age, 36 years) of benign bone tumours were treated surgically at a tertiary musculoskeletal oncology centre, between 2019 and 2021. Following curettage, the contained defects were managed with injectable beta-tricalcium phosphate/calcium sulfate (GeneX; Biocomposites Ltd., Keele, UK). The desired outcomes were early restoration of function and radiographic evidence of healing. No other graft materials were used in any of the patients. The mean follow-up was 24 months (range, 20–30 months). All patients in this series (100%) demonstrated radiographic evidence of healing and resumed their daily living activities. There were no tumour recurrences and no complications were encountered with the use of GeneX. In patients with contained defects following curettage of benign bone tumours, we found GeneX to be a safe and effective filling agent. These findings contrast with some existing studies that have reported local complications with the use of injectable beta-tricalcium phosphate/calcium sulfate.

Solitary enchondromas-diagnosis and surveillance : Danish guidelines

Enchondromas (EC) are frequent incidental findings on magnetic resonance imaging (MRI) performed for the diagnosis of joint pathology, especially observed on MRI examinations of the knee and shoulder. Enchondroma has potential for malignant transformation to chondrosarcoma (CS), and it may be difficult to distinguish EC from low-malignant CS on the basis of imaging or histopathology studies. Therefore, EC is mostly followed up to monitor any growth and/or changes indicating aggressive tumor.There is no consensual evidence on when and how to follow up patients with EC with regard to potential malignant transformation. Therefore, the Danish Multidisciplinary Cancer Groups initiated and supported the elaboration of Danish guidelines in 2020 based on a literature review. The guidelines are presented here, in addition to a summary of the background literature.

SATB2 is not a reliable diagnostic marker for distinguishing between oral osteosarcoma and fibro-osseous lesions of the jaws

OBJECTIVE

Special AT-rich binding protein 2 (SATB2) is an immunohistochemical marker for osteoblast differentiation. Our aim was to investigate SATB2 expression in oral osteosarcoma and other bone-producing oral tumors/reactive lesions to evaluate its usefulness as a diagnostic marker.

STUDY DESIGN

A total of 74 intraosseous and soft tissue bone-producing surgical samples and 10 samples of reactive bone tissue were stained with SATB2, including osteosarcoma/chondrosarcoma (n = 16), fibro-osseous lesions (n = 42), central giant cell granuloma (n = 6), osteoblastoma (n = 1), and gingival lesions (n = 9). Nuclear labeling of the stromal spindle cells and intensity of staining was scored and analyzed.

RESULTS

The intraosseous (n = 65/65) and soft tissue samples (n = 9/9) diffusely expressed SATB2. The strongest expression was observed in juvenile aggressive ossifying fibroma (n = 2/2). Weak SATB2 expression was observed in the stromal spindle cells adjacent to reactive bone tissue (periosteal bone reaction).

CONCLUSIONS

Our results indicate that SATB2 is not a reliable diagnostic marker for oral osteosarcoma but has practical use in detecting cells with osteoblast differentiation in histologic samples with scant bone production or in differentiating between a periosteal bone reaction and neoplastic bone induced by the tumor mesenchymal cells. Targeting SATB2 as an alternative therapy in oral osteosarcoma, fibro-osseous lesions, and central giant cell granuloma should be further investigated.

Aggressive Cranial Osteoblastoma of the Parietotemporo-Occipital Bone: A Case Report and Review of Literature with Special Emphasis on Recurrence/Residue

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

[Biphasic (dedifferentiated) osteosarcoma of the lung in the light of current ideas on biphasic tumors]

The paper presents a case of biphasic (dedifferentiated) osteosarcoma arising primarily on the lung, which has not previously encountered in the literature. It provides a detailed description of its clinical, instrumental, and morphological pattern. It also analyzes the literature on the study of primary pulmonary osteosarcoma and extraskeletal osteosarcoma with high-grade transformation. This clinical case is a clear example of classic biphasic sarcoma interpreted in the context of the phenomenon of biphasic tumors. Their most important aspects (terminology, morphology, biological behavior, and a mechanism of dedifferentiation) are highlighted; the key characteristics of biphasic sarcomas are listed.

Radiographic manifestations of fibroblastic osteosarcoma: A diagnostic challenge

Osteosarcoma is the most common primary bone tumor after plasma cell neoplasms. Osteosarcoma has diverse histological features and is characterized by the presence of malignant spindle cells and pluripotent neoplastic mesenchymal cells that produce immature bone, cartilage, and fibrous tissue. Osteosarcoma most frequently develops in the extremities of long bones, but can occur in the jaw in rare cases. The clinical and biological behavior of osteosarcoma of the jaw slightly differs from that of long-bone osteosarcoma. The incidence of jaw osteosarcoma is greater in the third to fourth decades of life, whereas long-bone osteosarcoma mostly occurs in the second decade of life. Osteosarcoma of the jaw has a lower tendency to metastasize and a better prognosis than long-bone osteosarcoma. Radiographically, osteosarcoma can present as a poorly-defined lytic, sclerotic, or mixed-density lesion with periosteal bone reaction response. Multi-detector computed tomography is useful for identifying the extent of bone destruction, as well as soft tissue involvement of the lesion. The current case report presents a fibroblastic osteosarcoma involving the left hemimandible with very unusual radiographic features.

Giant periosteal aggressive epithelioid osteoblastoma: 21-year-old male presents case in the midshaft of his femur

We report a rare case of giant periosteal osteoblastoma in the femur of a 21-year-old male. The patient presented with a painful, firm, non-tender mass in his left thigh. The pain was worse at night and was temporarily relieved with NSAIDS. He had no fevers, night sweats, or weight loss. The patient underwent preoperative radiological studies including plain radiographs, MRI, bone scan, and CT scan. An open biopsy was subsequently performed that was consistent with an aggressive, epithelioid osteoblastoma. Pathology demonstrated a neoplasm characterized by cohesive sheets of epithelioid osteoblasts, mixed with areas of conventional osteoblastoma displaying prominent osteoblastic rimming of woven bone trabeculae in a fibrovascular stroma. The patient subsequently underwent resection, cryosurgery, fixation, and bone grafting with cortical strut allografts. At final follow-up, 32 months postoperatively, there was no evidence of local recurrence. The patient had resumed all his normal activities. He could run without pain and had no restrictions with activities. The goal of this case report is to aid professionals in the diagnosis and treatment of highly uncommon aggressive osteoblastomas.

Immunoconjugates for Osteosarcoma Therapy: Preclinical Experiences and Future Perspectives

Osteosarcoma (OS) is an aggressive osteoid-producing tumor of mesenchymal origin, which represents the most common primary bone malignancy. It is characterized by a complex and frequently uncertain etiology. The current standard care for high-grade OS treatment is neoadjuvant chemotherapy, followed by surgery and post-operative chemotherapy. In order to ameliorate survival rates of patients, new therapeutic approaches have been evaluated, mainly immunotherapy with antibody-drug conjugates or immunoconjugates. These molecules consist of a carrier (frequently an antibody) joined by a linker to a toxic moiety (drug, radionuclide, or toxin). Although several clinical trials with immunoconjugates have been conducted, mainly in hematological tumors, their potential as therapeutic agents is relatively under-explored in many types of cancer. In this review, we report the immunoconjugates directed against OS surface antigens, considering the in vitro and in vivo studies. To date, several attempts have been made in preclinical settings, reporting encouraging results and demonstrating the validity of the idea. The clinical experience with glembatumumab vedotin may provide new insights into the real efficacy of antibody-drug conjugates for OS therapy, possibly giving more information about patient selection. Moreover, new opportunities could arise from the ongoing clinical trials in OS patients with unconjugated antibodies that could represent future candidates as carrier moieties of immunoconjugates.

Spontaneous shrinkage of solitary osteochondromas

OBJECTIVE

Osteochondromas are the most common benign bone tumors, and thus far, their spontaneous shrinkage is considered a rare phenomenon. This study was designed to investigate the exact ratio of remission to progressive or stable cases and analyze the mechanism of tumor regression on the basis of existing theories.

MATERIALS AND METHODS

We retrospectively collected images of solitary osteochondromas in patients from 1992 to 2013, excluding cases involving short-term follow-up periods and follow-up periods that ended before growth plate closure. A total of 121 patients were diagnosed and screened for study inclusion. Tumor shrinkage was measured by assessing three points on tumor contours to determine if they had regressed or vanished. Patterns of shrinkage were further divided on the basis of mechanisms described as incorporation, absorption, and fracture.

RESULTS

Seventeen patients (mean age at initial diagnosis 13.1 years) met the study inclusion criteria. Tumor morphological classifications were pedunculated (10 cases) and sessile (7 cases). Osteochondroma shrinkage was the most common outcome (8 cases), followed by stable osteochondromas (6 cases), and osteochondromas that had progressed (3 cases). Tumors with sessile morphology were more prone to shrinkage (6 of 7 cases) compared with those of pedunculated morphology (2 of 10 cases; p = 0.015). Among pedunculated cases, tumor shrinkage was via absorption. The timing of tumor growth cessation was related to the pattern of tumor shrinkage. Absorption mostly followed tumor growth cessation, whereas incorporation mostly preceded tumor growth cessation.

CONCLUSION

The shrinkage of osteochondromas appears less rare than was originally thought.

Systematic approach to musculoskeletal benign tumors

The radiologic workup of musculoskeletal tumors can be both cost-efficient and extremely helpful to the referring clinician if one proceeds in a thoughtful and logical manner. It should be remembered that plain films remain the most reliable imaging method for assessment of both biological activity and probable histologic diagnosis of an osseous lesion. Further investigations are of help to determine the extent of lesion and to help in staging. In order to do this, we have found it useful to include an assessment of 10 determinants in the description of a tumor. If these determinants are accurately described, the correct diagnosis or at least a limited differential diagnosis usually becomes obvious.

Giant cell tumor of bone revisited

Giant cell tumor (GCT) of bone is a locally aggressive benign neoplasm that is associated with a large biological spectrum ranging from latent benign to highly recurrent and occasionally metastatic malignant bone tumor. It accounts for 4–10% of all bone tumors and typically affects the meta-epiphyseal region of long bones of young adults. The most common site involved is the distal femur, followed by the distal radius, sacrum, and proximal humerus. Clinical symptoms are nonspecific and may include local pain, swelling, and limited range of motion of the adjacent joint. Radiographs and contrast-enhanced magnetic resonance imaging (MRI) are the imaging modalities of choice for diagnosis. Surgical treatment with curettage is the optimal treatment for local tumor control. A favorable clinical outcome is expected when the tumor is excised to tumor-free margins, however, for periarticular lesions this is usually accompanied with a suboptimal functional outcome. Local adjuvants have been used for improved curettage, in addition to systematic agents such as denosumab, bisphosphonates, or interferon alpha. This article aims to discuss the clinicopathological features, diagnosis, and treatments for GCT of bone.

Hypoxia-related microRNA-210 is a diagnostic marker for discriminating osteoblastoma and osteosarcoma

Osteoblastoma is a benign bone tumor that can often be difficult to distinguish from malignant osteosarcoma. Because misdiagnosis can result in unfavorable clinical outcomes, we have investigated microRNAs as potential diagnostic biomarkers for distinguishing between these two tumor types. Next generation RNA sequencing was used as an expression screen to evaluate >2,000 microRNAs present in tissue derived from rare formalin fixed paraffin embedded (FFPE) archival tumor specimens. MicroRNAs displaying the greatest ability to discriminate between these two tumors were validated on an independent tumor set, using qPCR assays. Initial screening by RNA-seq identified four microRNA biomarker candidates. Expression of three miRNAs (miR-451a, miR-144-3p, miR-486-5p) was higher in osteoblastoma, while the miR-210 was elevated in osteosarcoma. Validation of these microRNAs on an independent data set of 22 tumor specimens by qPCR revealed that miR-210 is the most discriminating marker. This microRNA displays low levels of expression across all of the osteoblastoma specimens and robust expression in the majority of the osteosarcoma specimens. Application of these biomarkers to a clinical test case showed that these microRNA biomarkers permit re-classification of a misdiagnosed FFPE tumor sample from osteoblastoma to osteosarcoma. Our findings establish that the hypoxia-related miR-210 is a discriminatory marker that distinguishes between osteoblastoma and osteosarcoma. This discovery provides a complementary molecular approach to support pathological classification of two diagnostically challenging musculoskeletal tumors. Because miR-210 is linked to the cellular hypoxia response, its detection may be linked to well-established pro-angiogenic and metastatic roles of hypoxia in osteosarcomas and other tumor cell types. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1137-1146, 2017.

Juvenile granulosa cell tumor associated with Ollier disease

Juvenile granulosa cell tumor (JGCT) is a rare neoplasm of childhood. Interestingly, it is known to be associated with Ollier disease, which is a rare bone disease characterized by multiple enchondromatosis. There is paucity of literature about the co-occurence of these two conditions. However, this association is noteworthy because these two conditions share a common pathogenesis. We report a case of JGCT in a 2.5-year-old female child in which multiple enchondromas mimicking bony metastasis were an incidental finding during routine workup for tumor staging, thus leading to a diagnosis of Ollier disease.

Pseudomyogenic hemangioendothelioma secondary to fibrous dysplasia of the left lower extremity in a 14-year-old female: a case report

Background

Pseudomyogenic hemangioendothelioma is a rare soft tissue tumor usually found in young adults, predominantly males. Fibrous dysplasia is a common benign bone tumor, which accounts for 5~7 % of all the primary benign bone tumors. However, pseudomyogenic hemangioendothelioma secondary to fibrous dysplasia is extremely rare. To the best of our knowledge, this is the first case of pseudomyogenic hemangioendothelioma secondary to fibrous dysplasia.

Case presentation

This study describes a case of a 14-year-old female who suffered from pseudomyogenic hemangioendothelioma secondary to fibrous dysplasia of the left lower extremity. The patient underwent two operations successively due to pathological fractures in the left femur and tibia in a local hospital. She was diagnosed with fibrous dysplasia according to the postoperative pathological examinations. However, less than 1 year later, she was diagnosed with a recurrence of fibrous dysplasia in her left femur during a follow-up in our hospital. She underwent a curettage and grafting in the left femur. Postoperative pathological examinations demonstrated the diagnosis of fibrous dysplasia. Nevertheless, she presented to our clinic with a chief complaint of pain and swelling in her left tibia and calcaneus 4 months later. The patient underwent fine-needle aspiration in her left tibia. According to the histological and immunohistochemical findings, the diagnosis of pseudomyogenic hemangioendothelioma was confirmed by an expert pathology consultant. Finally, the patient had to undergo an amputation of the left thigh. Postoperative pathological examinations confirmed the diagnosis of pseudomyogenic hemangioendothelioma. Postoperative follow-up at 3 months disclosed no evidence of recurrent disease and no residual side effects from therapy.

Conclusions

Pseudomyogenic hemangioendothelioma is a rare endothelial neoplasm which often mimics myoid and epithelioid tumors morphologically. For the diagnosis, the immunostaining is very important but not decisive and enough. Analysis based on any single factor or incomplete information may easily lead to arbitrary conclusion. Clinical information including age, gender, tumor location, disease course, and recurrence is important for appropriate diagnosis, and full understanding of the tumor is indispensable.

Total hip arthroplasty-related osteogenic osteosarcoma: case report and review of the literature

BACKGROUND

Orthopedic implant-related sarcoma is an exceedingly rare, but a known complication of total hip arthroplasty (THA).

CASE PRESENTATION

The authors describe clinical and radiologic features, histologic appearance, and treatment of osteogenic osteosarcoma located in the proximal femoral diaphysis associated with an unstable femoral prosthesis following THA in a 65-year-old male patient. The patient with HLA-B27 positive ankylosing spondylitis underwent arthroplasty 15 years ago.

CONCLUSIONS

The neoplastic process may be considered as an extraordinary complication of THA and might just be coincidental or the result of some derangement of the healing process in host tissue with no definitely proven hypothesis that the implants or their by-products are carcinogenic. The soluble chemical substances from the implanted prosthetic material are, at least in animals, suspected to play a vital role in the pathogenesis of the neoplastic transformation of the bone tissue. The presented case shall alert orthopedic surgeons to clinical, radiologic, and macroscopic similarities between a malignant tumor and benign lesions caused by wear debris at THA sites. At the examination of plane X-rays of patients with THA loosening, the differential diagnosis should always include osteogenic sarcoma, as well. To our knowledge, there have been only nine cases of THA-related osteogenic osteosarcomas described in the English-language literature.

Locus minoris resistentiae: An old but still valid way of thinking in medicine

Locus minoris resistentiae (lmr) refers to a body region more vulnerable than others. This ancient concept, which is also present in Achilles' and Siegfried's old epic myths, weaves through many fields of medicine. In any internal organ or external body region with a congenital or acquired altered defense capacity, a disease process may occur more easily than elsewhere. Illustrative instances are the appearance of hepatocarcinoma on a cirrhotic liver, the onset of lung carcinoma in a tuberculosis scar, cases of osteosarcoma arising in chronic osteomyelitis, and carcinoma complicating chronic cholelithiasis, just to name a few. In dermatology there are countless reports of privileged localization of cutaneous lesions on injured skin which, therefore, represents a typical condition of lmr. The Köbner phenomenon itself features the oldest, simplest, and most common example of lmr, because it denotes the appearance of new lesions pertaining to a previously present skin disorder at the sites of trauma or other insult. The modern transposition of this old but still valid way of thinking in medicine is the reading key of this issue, devoted to lmr in dermatology.

Osteosarcoma in Baboons (Papio spp)

Bone neoplasms in baboons (Papio spp) are rare, with only one confirmed case of osteosarcoma previously described in the literature. Over a 12-y period, 6 baboons at a national primate research center presented with naturally occurring osteosarcoma; 3 lesions affected the appendicular skeleton, and the remaining 3 were in the head (skull and mandible). The 6 cases presented were identified in members of a large outdoor-housed breeding colony. The subjects were not genetically related or exposed to the same research conditions. Diagnoses were made based on the presentation and radiographic findings, with histologic confirmation.

[Osteochondroma and multiple osteochondromas: recommendations on the diagnostics and follow-up with special consideration to the occurrence of secondary chondrosarcoma]

PURPOSE

Osteochondroma represents the most common form of benign bone tumor. Clinical manifestations include deformity of bone, compression of surrounding tissue and vascular or neurological compromise. Osteochondromas may be solitary (solitary osteochondroma, SO) or multiple (multiple osteochondromas MO). Recurrence after surgery is a known problem especially in MO and malignant transformation is rare but more common in MO than in solitary cases. Reliable recommendations regarding diagnostics and clinical follow-up are currently lacking.

PATIENTS AND METHODS

A comprehensive literature review and a review of own patient files with SO/MO treated between 2000 and 2011 in this hospital were performed. The age of patients at diagnosis, tumor localization, clinical aspects, recurrence and the risk of malignant transformation in secondary (i.e. epiexostotic) chondrosarcoma were analyzed. The follow-up including patients who received surgery ranged between 2 and 127 months for patients with SO and between 2 and 84 months for MO.

RESULTS

A total of 39 patients with SO from this hospital were included in the study. Out of 36 patients who received surgery 3 recurrences were registered after an average time of 62 months. In addition, 11 patients with MO were identified and all received surgery. In 5 out of 11 cases recurrences occurred after an average time of 20.6 months. Secondary chondrosarcomas were not recorded in this series. According to the literature an increased risk of malignant transformation was found for osteochondromas of the axial skeleton, in the proximal aspect of the extremities, as well as for recurrent tumors and for MO. Pain and/or increase in size of lesions after skeletal maturation were the most common clinical signs of transformation. There was a wide time interval between the initial diagnosis and the development of secondary chondrosarcoma. In MO secondary chondrosarcoma has been described before skeletal maturity.

CONCLUSIONS

The risk of malignant transformation of SO is generally low. Axial lesions as well as recurrent osteochondromas and MO seem to have an increased risk of malignant transformation. The follow-up, requiring sufficient primary diagnostics, includes regular self-control and can usually be clinically carried out in more peripherally located lesions but in certain cases supplementary X-ray imaging is needed. In cases of anatomical regions which are more difficult to access manually, follow-up examination by magnetic resonance imaging (MRI) is the method of choice. Especially MO patients seem to benefit from long-term follow-up: when the tumor is located in the trunk and in (proximal) long bones MRI or whole-body MRI, respectively, should be performed once a year after skeletal maturity because of the higher risk of malignant transformation in these patients.

Five polyostotic conditions that general orthopedic surgeons should recognize (or should not miss)

General orthopedic surgeons frequently encounter patients with conditions affecting multiple bones. It is important to recognize common polyostotic diseases. This article describes five polyostotic conditions: Multipe Enchondromatosis (Ollier Disease and Maffucci syndrome), Multiple Hereditary Exostosis (Diaphyseal Aclasis), Fibrous Dysplasia (McCune-Albright syndrome and Mazabraud syndrome), Paget's Disease of bone (Osteitis Deformans), and Skeletal Metastases. This is a survey of the clinical, pathologic and radiographic features that assist in diagnosing these conditions. Also, an overview of the laboratory findings, treatment, follow-up, and prognosis is presented. Recognizing these diseases will aid in prompt and accurate diagnosis and appropriate referral and therapy.

A rare case of enchondromatosis of the knees and hands with involvement of Hoffa's fat pad and peri-articular soft-tissues

We report a case of a 56-year old man with chronic pain in both knees for several years. This patient had already undergone surgery on his left knee in 2002 after an x-ray showed multiple lytic and well margined lesions in the distal femur and proximal tibia with ground-glass matrix, involving Hoffa's fat pad and the patellar ligament. Histology was consistent with an enchondroma. The most recent MRI examination showed enchondromatosis involving both knees with bilateral extension into Hoffa's fat pad and the patellar ligament. Subsequently, we performed an additional radiographic examination of the hands and feet, as well as an MRI of both hands to identify other possible enchondromas in the most common sites for this disease. Enchondromatosis with soft tissue involvement is extremely rare, and involvement of Hoffa's fat pad has not been reported in the scientific literature. The clinical presentation of this case and the general aspects of Enchondromatosis are discussed.

Sarcomatous transformation (Leiomyosarcoma) in polyostotic fibrous dysplagia

Malignant changes in polyostotic fibrous dysplasia are very rare. Most common malignancies reported are osteosarcoma and fibrosarcoma, chondrosarcoma and malignant fibrous histiocytoma. Here, we report a previously diagnosed case of fibrous dysplasia who has developed leiomyosarcoma; diagnosis of which was delayed for about one year despite repeated fine needle aspiration and open biopsy.

Fibrous dysplasia

Fibrous dysplasia is an uncommon bone disease. The diagnosis is usually not difficult, given the symptoms, radiology, and histology. The gene involved is the α subunit of the G-protein receptor. Recent innovation in molecular pathology has helped us understand the mechanism of disease pathogenesis. The treatment of fibrous dysplasia is limited to maintenance of maximum bone density. Surgical reinforcement is used to treat bowing deformities and fractures as they occur. Malignant transformation of fibrous dysplasia is rare. Currently, there is no therapy for preventing the disease from advancing or for malignant transformation.

Array comparative genomic hybridization in osteosarcoma

Osteosarcoma, the most frequent primary bone tumor, is a malignant mesenchymal sarcoma with a peak incidence in young children and adolescents. Left untreated, it progresses relentlessly to local and systemic disease, ultimately leading to death within months. Genomically, osteosarcomas are aneuploid with chaotic karyotypes, lacking the pathognomonic genetic rearrangements characteristic of most sarcomas. The familial genetics of osteosarcoma helped in elucidating some of the etiological molecular disruptions, such as the tumor suppressor genes RB1 in retinoblastoma and TP53 in Li-Fraumeni, and RECQL4 involved in DNA repair/replication in Rothmund-Thomson syndrome. Genomic profiling approaches such as array comparative genomic hybridization (aCGH) have provided additional insights concerning the mechanisms responsible for generating complex osteosarcoma genomes. This chapter provides a brief introduction to the clinical features of conventional osteosarcoma, the predominant subtypes, and a general overview of materials and analytical methods of osteosarcoma aCGH, followed by a more detailed literature overview of aCGH studies and a discussion of emerging genes, molecular mechanisms, and their clinical implications, as well as more recent application of integrative genomics in osteosarcoma. aCHG is helping elucidate genomic events leading to tumor development and evolution as well as identification of prognostic markers and therapeutic targets in osteosarcoma.

Osteochondroma with metaphyseal abnormalities after total body irradiation followed by stem cell transplantation

The occurrence of osteochondroma after total body irradiation (TBI) followed by stem cell transplantation (SCT) in our institutions was described, and its clinical significance discussed. Of 305 cases treated with SCT using TBI conditioning from 1980 to 2001, 4 cases of osteochondroma were identified on clinical examination. Mean age at the time of TBI was 4.4 years (range, 1.6 to 8.0). One patient developed multiple osteochondromas. All 4 cases showed metaphyseal abnormalities, including sclerotic metaphyseal lesion, fraying, and longitudinal striation, in the area where osteochondromas occurred. Only 1 patient required resection of the tumor due to pain. Two cases had other skeletal abnormalities including slipped capital femoral epiphysis and valgus-knee deformity, which required surgical intervention to prevent or correct these deformities. Osteochondroma is one of the complications developing after TBI, possibly concurrently with the metaphyseal abnormalities as seen on radiographs. However, clinical problems arising from osteochondroma are minimal, and surgical intervention is necessary in limited cases.

Is bone scintigraphy necessary in the initial surgical staging of chondrosarcoma of bone?

OBJECTIVE

To assess the value of whole-body bone scintigraphy in the initial surgical staging of chondrosarcoma of bone.

METHODS

A retrospective review was conducted of the bone scintigraphy reports of a large series of patients with peripheral or central chondrosarcoma of bone treated in a specialist orthopaedic oncology unit over a 13-year period. Abnormal findings were correlated against other imaging, histological grade and the impact on surgical staging.

RESULTS

A total of 195 chondrosarcomas were identified in 188 patients. In 120 (63.8%) patients the reports of bone scintigraphy noted increased activity at the site of one or more chondrosarcomas. In one patient the tumour was outside the field-of-view of the scan, and in the remaining 67 (35.6%) cases, there was increased activity at the site of the chondrosarcoma and further abnormal activity in other areas of the skeleton. Causes of these additional areas of activity included degenerative joint disease, Paget's disease and in one case a previously undiagnosed melanoma metastasis. No cases of skeletal metastases from the chondrosarcoma were found in this series. Multifocal chondrosarcomas were identified in three cases. In two it was considered that all the tumours would have been adequately revealed on the initial MR imaging staging studies. In only the third multifocal case was an unsuspected, further presumed low-grade, central chondrosarcoma identified in the opposite asymptomatic femur. Although this case revealed an unexpected finding the impact on surgical staging was limited as it was decided to employ a watch-and-wait policy for this tumour.

CONCLUSION

There is little role for the routine use of whole-body bone scintigraphy in the initial surgical staging in patients with chondrosarcoma of bone irrespective of the histological grade.

Osteosarcoma: Differential Diagnostic Considerations

Accurate diagnosis of bone-forming tumors, including correct subclassification of osteogenic sarcoma is critical for determination of appropriate clinical management and prediction of patient outcome. The morphologic spectrum of osteogenic sarcoma is extensive, however, and its histologic mimics are numerous. This review focuses on the major differential diagnoses of the specific subtypes of osteosarcoma, presents summaries of various diagnoses, and provides tips to overcoming pitfalls in diagnosis.

Resected osteochondroma of the rib in an elderly patient

Solitary osteochondroma of the rib is a rare primary chest wall tumor. Herein, we report a case of a successfully resected osteochondroma of the rib. The patient was a 73-year-old asymptomatic woman who came to our hospital regularly for treatment of hypertension and hyperlipidemia. A checkup chest roentgenogram showed a shadow at the right anterior chest wall consistent with a mass, and computed tomography showed a tumor arising from the right fourth rib. Because it was impossible to exclude completely the diagnosis of a well-differentiated chondrosarcoma, we performed resection of the right anterior chest wall and a re construction with a rigid prosthesis. The post operative course of the patient was unremarkable. The final pathological diagnosis of the rib tumor was osteochondroma.

Inflammation and cancer: macrophage migration inhibitory factor (MIF)--the potential missing link

Macrophage migration inhibitory factor (MIF) was the original cytokine, described almost 50 years ago and has since been revealed to be an important player in pro-inflammatory diseases. Recent work using MIF mouse models has revealed new roles for MIF. In this review, we present an increasing body of evidence implicating the key pro-inflammatory cytokine MIF in specific biological activities related directly to cancer growth or contributing towards a microenvironment favouring cancer progression.

Osteosarcoma in a pregnant patient with McCune-Albright syndrome

Malignant transformation of fibrous dysplasia is very rare and has not been previously described in patients with McCune-Albright syndrome in the absence of radiation treatment during gestation. Here, we report a 38-year-old pregnant woman with McCune-Albright syndrome and acromegaly accompanied by osteosarcoma. The patient was in the 6th week of pregnancy, when she visited our hospital. She had multiple fibrous dysplasia, skin pigmentation, and acromegaly. The markedly high bone turnover rate during pregnancy tended to decrease after a normal delivery. Fibrous dysplasia of the lower jaw rapidly increased in the 37th week of pregnancy, and the tumor was surgically resected after delivery. Pathological examination of the resected tumor revealed fibrous dysplasia admixed with osteosarcoma containing chondroblastic and osteoblastic tissue. We firstly reported a case of osteosarcoma in a patient with McCune-Albright syndrome, which rapidly progressed during pregnancy.

Osteoblastoma and osteoid osteoma: morphofunctional characterization by MRI and dynamic F-18 FDG PET/CT before and after radiofrequency ablation

Osteoblastoma (OB) and osteoid osteoma (OO) are benign bone-forming tumors frequently involving vertebrae and long bones of the extremities. Because of their similar histopathological features, distinction between OB and OO is mostly based on size criteria. CT and MRI represent the cornerstone of noninvasive diagnostic procedures, as they provide excellent morphologic details and often obviate the need for confirmatory biopsy. Bone scan is a complementary, highly sensitive functional technique particularly useful for detection of vertebral OO. F-18 FDG PET/CT could have potentiality in diagnosis and post therapeutic evaluation of patients with OB and OO. We report MRI and dynamic F-18 FDG PET/CT results obtained before radiofrequency or laser ablation from 3 patients with an OB of the right L5 pedicle, an OB of the left talus and an OO of the right acetabulum. Both patients with OB underwent posttherapeutic evaluation to confirm the effectiveness of percutaneous radiofrequency ablation.

Secondary osteosarcoma arising in fibrous dysplasia, case report

Malignant transformation of fibrous dysplasia is very rare. The frequency is increased in polyostotic forms, in McCune-Albright and Mazabraud's syndromes and previously irradiated cases. Pain, which is rapidly becoming worse over a short period unrelated to trauma is the most alarming symptom. Early radiological features of sarcomatous transformation are moth-eaten or cystic areas of osteolysis, cortical destruction and gradual formation of a soft tissue mass. The prognosis is unfavorable as most of the cases are in an advanced stage in the time of diagnosis. We present an unusual case of unsuspected secondary osteosarcoma arising in a previously unirradiated, monostotic fibrous dysplasia. A 46-year-old woman was admitted with hip pain, which worsened after a minor trauma occurred 1 year ago. Plain graphies of left femur showed a well-delineated lesion with endosteal scalloping and areas having a ground-glass appearance. The MRI revealed minimal contrast enhancement but no heterogenous signal intensity, cortical destruction, periost reaction or accompanying soft tissue component was noted. The lesion was initially curetted. But being diagnosed as osteosarcoma histologically, classical osteosarcoma protocol pre and postoperative chemotherapy was applied. Resected femur showed areas of fibrous dysplasia admixed with osteosarcoma having fibroblastic, chondroblastic and osteoblastic areas that were focally invading the soft tissue. Tumor viability was estimated as 95%. The clinical course worsened rapidly after the operation. She did not respond to postoperative chemotherapy and lost with pulmonary metastases less than a years' time after the operation. The case is presented to increase awareness on the possibility of malignant transformation in an otherwise unsuspected fibrous dysplasia.

Concurrent osteochondroma and osteoblastoma of the proximal humeral shaft

We present what we believe is the first reported case of synchronous osteochondroma and osteoblastoma, occurring in the proximal humerus of a young man. A 15-year-old boy presented with a painful left arm mass for 3 months. A firm mass was palpable in the proximal medial arm, and he had mild triceps weakness secondary to pain. Imaging showed an eccentric lesion involving the proximal one-third of the humerus, with central lysis, surrounding sclerosis and edema, endosteal scalloping, and cortical thinning and expansion. The humeral diaphysis contained a bony exostosis with corticomedullary continuity, consistent with an osteochondroma with a cartilage cap <5 mm thick. Within the proximal portion of the osteochondroma was a 2-cm, edematous, rim-enhancing cystic lesion, concerning for a secondary process such as malignant transformation. On open biopsy, the mass grossly appeared to be a sessile osteochondroma, and was removed with a rongeur. The cystic lesion was curetted out of the bone. Pathology confirmed that the raised lesion was an osteochondroma. The cystic lesion contained osteoblasts in a matrix of osteoid and immature bone, characteristic of an osteoblastoma. The multidisciplinary team agreed that this was an osteoblastoma within an exostosis. At follow-up, the patient's pain had fully resolved and radiographs showed good early healing. We wished to document the extraordinary, simultaneous existence of an osteochondroma and adjacent osteoblastoma in the proximal humerus of a young patient. Although similar in presentation, the tumors consist of cells of different origins, making the pathogenesis unclear.

Secondary chondrosarcoma in cartilage bone tumors: report of 32 patients

BACKGROUND

Secondary malignancies arising from benign bone tumors are rare. Their recognition and diagnosis are difficult, and their slow growth and late recurrence require long-term follow-up. In this study, malignant transformation rates of various histological types of benign cartilage-forming bone tumors in large series were evaluated.

METHODS

Between 1986 and 2004, a retrospective analysis of 627 cartilage-forming benign bone tumors revealed that 32 patients had malignant transformation. Of the 32 patients, 14 had solitary osteochondromas, 10 had multiple osteochondromas, 6 had a solitary enchondroma, 1 had Ollier's disease, and 1 had Maffucci's syndrome. The patient with Ollier's disease had two chondrosarcomas, and one patient with multiple osteochondroma had three chondrosarcomas. The cases were included in the study only when complete clinical documentation, radiological records, and histological analyses were available.

RESULTS

The rate of malignant transformation for cartilage-originating tumors was 5.1% (solitary osteochondromas 4.2%, multiple osteochondromas 9.2%, solitary enchondromas 4.2%). The average time between the initial diagnosis and malignant transformation was 9.8 years. The most common site of involvement was the proximal portion of the femur. The tumors generally were well differentiated. The mean follow-up period was 57.3 months. Five patients (15.6%) died of tumor recurrence or metastasis at an average of 20.6 months. One patient is alive with tumor at 104 months.

CONCLUSIONS

Cartilage-forming benign bone tumors are rather prone to undergo malignant transformation. Although malignant transformation of a benign bone tumor is a rarely encountered situation, orthopedic surgeons should be cautious while following patients with a benign bone neoplasm. Early recognition and appropriate surgical treatment are required to achieve successful outcomes. The rate of local recurrence in secondary chondrosarcomas depends not only on adequate surgical treatment but also on the localization and histological grade.