Areas Of Bone Destruction Research Articles

Effect of glucocorticoids on osteoclast function in a mouse model of bone necrosis.

Osteonecrosis, also termed aseptic necrosis, is the cellular death of bone components due to interruption of the blood supply. Glucocorticoid (GC) therapy is a common non-traumatic cause of osteonecrosis. However, the mechanism by which GCs induce osteonecrosis remains to be elucidated. The aim of the present study was to investigate the effects of GCs on osteoclast and osteoblast differentiation and function in a GC-induced osteonecrosis mouse model. BALB/c male mice (n=40; 4-weeks-old) were treated with dexamethasone and asparaginase for 8 weeks. The control group (n=20) was administered normal saline. The results demonstrated that the GC-treated group had a lower mean weight compared with the control group. Morphologically, 16/37 (43%) mice demonstrated significant osteonecrotic lesions in the GC-treated group. However, osteonecrotic lesions were not observed in the mice of the control group. Furthermore, immunohistochemistry demonstrated that the GC-treated group had a higher level of osteoprotegerin compared with the control group, without any change in the expression of receptor activator of nuclear factor-κB ligand. In addition, tartarate-resistant acid-phosphatase staining demonstrated significantly decreased osteoclasts in the areas of bone destruction in the GCs-treated group. Furthermore, the present study demonstrated that GCs increased expression levels of osterix and osteocalcin, and decreased expression of matrix metallopeptidase-9 to regulate the differentiation and function of osteoblasts and osteoclasts. The results of the present study suggested that GCs influence bone remolding resulting in decreased osteoclasts formation/differentiation. Therefore, regulating the differentiation and activity of the osteoclasts may be beneficial to the control and treatment of osteonecrosis.

Muramyl dipeptide enhances lipopolysaccharide-induced osteoclast formation and bone resorption through increased RANKL expression in stromal cells.

Lipopolysaccharide (LPS) is bacterial cell wall component capable of inducing osteoclast formation and pathological bone resorption. Muramyl dipeptide (MDP), the minimal essential structural unit responsible for the immunological activity of peptidoglycans, is ubiquitously expressed by bacterium. In this study, we investigated the effect of MDP in LPS-induced osteoclast formation and bone resorption. LPS was administered with or without MDP into the supracalvariae of mice. The number of osteoclasts, the level of mRNA for cathepsin K and tartrate-resistant acid phosphatase (TRAP), the ratio of the bone destruction area, the level of tartrate-resistant acid phosphatase form 5b (TRACP 5b), and C-terminal telopeptides fragments of type I collagen as a marker of bone resorption in mice administrated both LPS and MDP were higher than those in mice administrated LPS or MDP alone. On the other hand, MDP had no effect on osteoclastogenesis in parathyroid hormone administrated mice. MDP enhanced LPS-induced receptor activator of NF-κB ligand (RANKL) expression and Toll-like receptor 4 (TLR4) expression in vivo and in stromal cells in vitro. MDP also enhanced LPS-induced mitogen-activated protein kinase (MAPK) signaling, including ERK, p38, and JNK, in stromal cells. These results suggest that MDP might play an important role in pathological bone resorption in bacterial infection diseases.

Myeloma Cells Switch Osteoblastogenesis to Adipogenesis and Suppress Bone Formation

Bone destruction is a hallmark of myeloma, and has a severe impact on patients’ quality of life and survival. Unfortunately, current treatment only offers moderate palliative effects, and this disease remains incurable. The bone changes in myeloma patients results from increased osteoclast-mediated bone resorption and decreased osteoblast-mediated bone formation. In particular, new bone formation that usually occurs at sites of previously resorbed bones is deeply suppressed; as a result, areas of bone destruction rarely heal. Previous studies have shown that myeloma cells inhibit osteoblast differentiation from mesenchymal stem cells (MSCs), and the Wnt/b-catenin signaling pathway is suppressed via myeloma-produced Wnt antagonists such as dickkopf-1. However, the role of dickkopf-1 in myeloma-induced inhibition of bone formation remains controversial since myeloma cells alone do not produce sufficient dickkopf-1 to suppress osteoblast differentiation. In addition, the administration of an antibody against dickkopf-1 in myeloma patients failed to restore new bone formation, indicating there must be an additional mechanism for inhibition of osteoblast differentiation seen in myeloma. While MSCs can differentiate into mature osteoblasts, they are also capable of differentiating into adipocytes, which is a major cell type in marrow stroma. We observed that myeloma cells (cell lines and primary cells isolated from myeloma patients’ bone marrow) injected into human or mouse bone not only reduced osteoblast number, but also increased adipocyte number and activity in bone marrow. Similar observations were seen in the clinical setting where collections of adipocytes were found in the bone marrow of newly diagnosed, untreated myeloma patients. Patients with greater bone destruction had higher adipocyte numbers than those in patients with less bone destruction, indicating a relationship among myeloma cells, adipogenesis, and osteoblastogenesis. We hypothesized that inhibition of osteoblast differentiation is a consequence of myeloma-dependent alterations in the control of the MSCs’ fate into osteoblasts or into adipocytes. In our studies, we co-cultured MSCs with myeloma cells in a mixed medium (that contained both adipocyte and osteoblast media), and we observed co-culture with myeloma cells induced more adipocyte than osteoblast formation. Moreover, co-culture with myeloma cells enhanced adipocyte differentiation in vitro. Interestingly, separation of the cells by transwell inserts significantly reduced such effect. By analysis of the adhesion molecules in myeloma cells, we identified integrin α4β1 as a novel contributor in regulation of adipogenesis and osteoblastogenesis. Thus, our studies indicate that in the presence of myeloma cells, MSCs may be more prone to differentiate into adipocytes than into osteoblasts via α4β1. Our studies also suggest the development of new strategies to improve the care of myeloma patients with bone destruction by targeting α4β1 and its signaling pathways. DisclosuresNo relevant conflicts of interest to declare.

Fibroblasts Regulate Variable Aggressiveness of Syndromic Keratocystic and Non-syndromic Odontogenic Tumors

Keratocystic odontogenic tumors (KCOTs) are jaw lesions that can be either sporadic or associated with nevoid basal cell carcinoma syndrome, which typically occurs as multiple, aggressive lesions that can lead to large areas of bone destruction and resorption and cause major impairment and even jaw fracture. To clarify the role of fibroblasts in the aggressivness of syndromic (S-) as compared with non-syndromic (NS-) KCOTs, we assessed fibroblasts derived from 16 S- and NS-KCOTs for differences in cell proliferation, multilineage differentiation potential, alkaline phosphatase activity, and osteoclastogenic potential. S-KCOT fibroblasts had proliferative and osteoclastogenic capacity higher than those from NS-KCOTs, as evidenced by higher numbers of tartrate-resistant acid-phosphatase-positive multinuclear cells, expression of cyclooxygenase 2, and ratio of receptor activator of nuclear factor–kappa B ligand to osteoprotegerin. The osteogenic potential was higher for S- than for NS-KCOT fibroblasts and was associated with lower mRNA expression of runt-related transcription factor 2, collagen type I α1, osteocalcin, and osteopontin as well as reduced alkaline phosphatase activity. These results suggest that the distinct characteristics of fibroblasts in KCOTs are responsible for the greater aggressiveness observed in the syndromic subtype. Abbreviations: AP, alkaline phosphatase; CK, cytokeratin; COL1A1, collagen type I α1; COX-2, cyclooxygenase-2; GM-CSF, granulocyte-macrophage colony-stimulating factor; IL-1α, interleukin 1α; KCOT, keratocystic odontogenic tumor; NBCCS, nevoid basal cell carcinoma syndrome; NS-KCOT, non-syndrome-associated KCOT; OCN, osteocalcin; OPG, osteoprotegerin; OPN, osteopontin; RANKL, receptor activator of nuclear factor-kappa B ligand; Runx2, runt-related transcription factor 2; S-KCOT, syndrome-associated KCOT; TAF, tumor-associated fibroblast; and TRAP, tartrate-resistant acid phosphatase.

A rare occurrence of a malignant ovarian steroid cell tumor not otherwise specified: A case report and literature review.

Steroid cell tumors not otherwise specified (NOS) are a rare subgroup of sex cord-stromal tumors. The tumors can occur at any age, although the mean age of occurrence is 43 years old. The majority are benign, but have the capability of producing one or more steroids associated with virilization. The present study reports the case of a 29-year-old female who presented to the Second Xiangya Hospital suffering from lower back and leg pain that had persisted for five months. The patient had regular menstrual cycles and no virilization symptoms were present. Laboratory investigations revealed normal hormone levels. Multiple areas of bone destruction and a right ovarian mass were confirmed via positron emission tomography/computed tomography. The patient underwent an exploratory laparotomy, and a mass measuring ~6 cm in diameter was subsequently identified in the right ovary. A right salpingo-oophorectomy and pelvic washings for cytology were performed. Histopathological studies confirmed the diagnosis of a malignant steroid cell tumor NOS of the right ovary. The patient underwent eight cycles of chemotherapy (docetaxel, 120 mg and nedaplatin, 80 mg). The patient continued to have relatively good health, with no deterioration of the condition for one year and a half, however, the disease progressed and the patient succumbed to brain metastases six months later.

Mesenchymal stem cells markedly suppress inflammatory bone destruction in rats with adjuvant-induced arthritis

Mesenchymal stem cells (MSCs) have potential to differentiate into multiple cell lineages. Recently, it was shown that MSCs also have anti-inflammatory and immunomodulatory functions. In this report, we investigated the regulatory function of MSCs in the development of inflammatory bone destruction in rats with adjuvant-induced arthritis (AA rats). MSCs were isolated from rat bone marrow tissues, expanded in the presence of basic FGF, and intraperitoneally injected into AA rats. MSC administration significantly suppressed inflammatory parameters: swelling score, swelling width, and thickness of hind paw. Radiographic evaluation indicated that MSC significantly suppressed bone destruction. Histological analysis showed that administration of MSCs markedly suppressed osteoclastogenesis in AA rats. To further delineate their effects on osteoclastogenesis, MSCs were added to in vitro bone marrow cultures undergoing osteoclastogenesis. MSCs significantly suppressed osteoclastogenesis in this system. Chemokine receptor expression in MSCs was assessed by RT-PCR, and a chemotactic assay was performed using a transwell culture system. MSCs showed significant chemotaxis to MIP-1α (CCL3) and SDF-1α (CXCL12), chemokines preferentially expressed in the area of inflammatory bone destruction. Furthermore, MSCs expressed IL-10 and osteoprotegerin, cytokines that suppress osteoclastogenesis. These data suggest that recruitment of MSC to the area of bone destruction in AA rats could suppress inflammatory bone destruction and raise the possibility that MSCs may have potential for the treatment of inflammatory bone destruction in arthritis.

Clinical investigation of bacterial species and endotoxin in endodontic infection and evaluation of root canal content activity against macrophages by cytokine production

This study investigated the presence of different Gram-negative bacterial species and the levels of endotoxins found in primary endodontic infection (PEI), determining their stimulation ability against macrophages through the levels of interleukin (IL)-1, IL-6, IL-10, and tumor necrosis factor alpha (TNF-α), and evaluated their relationship with clinical and radiographic findings. Samples were taken from 21 root canals with primary endodontic infection with apical periodontitis (PEIAP). Molecular techniques were used for bacterial detection. Limulus amebocyte lysate assay was used to measure endotoxins. Pro-inflammatory cytokines were measured by ELISA assay. All samples were positive for bacterial DNA (21/21). Prevotella nigrescens (57.2%) was the most frequent species. Higher levels of endotoxins were found in teeth with pain on palpation and exudation (all p < 0.05). Positive correlations were found between endotoxins and the levels of TNF-α and IL-1β, whereas a negative correlation was found between endotoxin and the amount of IL-10 (p < 0.05). Endotoxin levels were found to be a risk factor for exudation and increased the number of Gram-negative bacterial species for the presence of a larger area of bone destruction (all p < 0.05). A wide variety of Gram-negative bacterial species are involved in primary endodontic infection, with participation of different Treponema species. Thus, the levels of endotoxins and the number of Gram-negative bacteria species present in root canals were considered risk factors for the severity of endodontic infection. The present study revealed that Gram-negative bacterial species and endotoxins play an important role in the development of signs/symptoms and the severity of bone destruction, this knowledge is essential for the establishment of an effective therapy.

The radiation-induced jaw osteosarcoma: CT imaging features

To evaluate the CT features of radiation-induced jaw osteosarcoma(RIJOS) developed after therapeutic irradiation for a variety of nonosseous lesions. The demographic and CT findings of thirteen patients with RIJOS were reviewed retrospectively.Observation items included location, bone destruction, mineralized tumor matrix, periosteal reaction, soft tissue extension and calcification.Of the thirteen patients, twelve were male and one was female. The mean age was 48 years (range: 29-68 years).Five patients had tumors in the maxilla and eight in the mandible. All the patients underwent tumor resection. The latent period before development of RIJOS ranged from 3.5 to 14 years (mean, 11 years).In all thirteen patients, eight tumors were osteoblastic, with one osteolytic and four mixed lesions.Osteoid tumor matrix mineralization was present in twelve patients. Periosteal reaction was identified in 11 cases.Soft-tissue extension was present in all patients beyond the area of bone destruction. The characteristic CT imaging of RIJOS showed the bone destruction associated with a large number of mineralized tumor matrix and significant soft tissue extension in the original radiation field after radiotherapy. CT findings could play an important role in identifying the tumor and pre-operative assessment.

Osteolysis in Lumbar Interbody Fusions: The Role of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2)

ABSTRACT Osteolysis may occur following lumbar interbody fusion procedures in which recombinant human bone morphogenetic protein-2, more commonly known as rhBMP-2, is used. The actual incidence of this process is unknown. Osteolysis results from an osteoclastic, rather than an osteoblastic response to rhBMP-2 and its carrier on trabecular vertebral bone, early in the sequence of bone graft healing. This osteoclastic response may represent an idiosyncratic reaction in those affected. The patient usually does well in the immediate postoperative period with resolution of their preoperative complaints of axial and radicular pain. However, at 4 to 12 weeks following the index surgery, the patient experiences a recurrence of severe back and radicular pain corresponding to the dermatomal level(s) operated upon. Laboratory studies including erythrocyte sedimentation rate, C reactive protein, and cultures are negative for infection. Imaging studies show areas of bone destruction and cyst formation containing fluid. In the majority of post-operative patients with osteolysis, there is an osteoblastic healing response with symptom resolution. Supportive, nonoperative care is usually effective in managing the patient. Nasca RJ. Osteolysis in Lumbar Interbody Fusions: The Role of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2). The Duke Orthop J 2012;2(1):50-54.

The Role of Digital Tomosynthesis In the Staging of Newly Diagnosed Multiple Myeloma: Preliminary Data

AbstractAbstract 4057 Introduction:Multiple myeloma (MM) is a malignant plasma cell disorder which involves the skeleton in more than 80% of patients at diagnosis. Bone lesions in MM are screened with radiological skeletal bone survey (SBS) due to its low cost and widespread availability. Even though bone lesions can be missed by SBS, more sensitive newer imaging techniques are not currently recommended for routine use due to low availability, complicated methodology, and cost. X-ray digital tomosynthesis (DT) is a technique for producing thin slice images using conventional x-ray systems to maximize in-plane spatial resolution. DT has already been described for several mammographic, dental and thoracic applications to reduce overlap of tissue, but has not been studied in MM. The aim of our study was to determine the usefulness of DT in the staging of myeloma and to assess its strengths and limitations. Patients and Methods:We are conducting a prospective IRB approved study that has currently enrolled 19 newly diagnosed MM or Monoclonal Gammopathy of Undetermined Significance (MGUS) patients. Our target study population is 50 patients. Diagnosis and staging were made according to standard Durie-Salmon (DS) criteria. All the patients that were consented for our study underwent DT and SBS on the same day or within 60 days of each other (average 6.2 days) before treatment. Imaging findings from DT were compared to those seen in SBS with regard to the number and site of lesions detected. DT added coronal views of the thoracolumbar spine and pelvis to the routine SBS. These sites were chosen because they include a large percentage of the hematopoetically active marrow, are a significant source of morbidity, and are frequently obscured on SBS. A senior radiology resident and a Musculoskeletal fellowship trained (MSK) radiologist initially reviewed DT images independently and subsequently those images were reviewed together to achieve inter-observer agreement. Both of these imagers were blinded to the results of the skeletal survey. A different MSK radiologist, who was blinded to the DT results, interpreted the SBS. Results:Comparing DT to SBS, it was found that in 9 out of 19 patients (47.3%), DT detected more lesions (Table 1). Three out of 19 patients (15.7%) had a change in their staging due to findings seen in the DT study (upstaged from IA to IIIA, IB to IIIB and MGUS to IIIA). Nine out of 19 patients (47.3%) had negative myeloma bone involvement on both DT and SBS. One out of 19 patients (5.2%) had a suspicious lesion seen on the SBS that was cleared as negative with DT. Twelve patients were male, seven patients were female. The average age was 65.Sample lytic lesions on DT: [Display omitted] [Display omitted] [Display omitted] Discussion:In MM, imaging is needed to determine the stage of disease and to anticipate impending pathologic fractures. The prognostic value of bone involvement is exemplified by the fact that the traditionally used DS staging system includes radiographically evident lytic bone lesions as a criterion. The use of magnetic resonance imaging (MRI) and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) with computed tomography (CT) have been studied in MM with varied results. Previous studies suggest that both FDG-PET in combination with low-dose CT and whole-body MRI might be more sensitive than SBS for screening multiple myeloma lesions. However the identification of marrow invasion in these methods is not specific for myelomatous bony destruction, and may need to be differentiated from other infiltrative processes such as hemangiomas and marrow reconversion in anemia. Marrow imaging might result in an over-staging without clear benefits for the patients. Our preliminary data in a small number of cases suggest that there is a group of patients in whom DT might detect other unsuspected sites of bone involvement. Digital Tomosynthesis resulted in more accurate staging in a small group of patients that would have been otherwise under-staged. Furthermore unrecognized areas of bone destruction were identified which rendered some patients eligible for bisphosphonates and palliative radiation therapy due to the newly discovered lesions seen on DT. Conclusions:Digital Tomosynthesis demonstrated increased sensitivity in the detection of osseous MM in the thoracolumbar spine and pelvis. Therefore, the preliminary data from our small prospective study shows encouraging results for the use of digital DT in the initial diagnosis and staging of MM. Disclosures:No relevant conflicts of interest to declare.

Computed tomography findings in radiation-induced osteosarcoma of the jaws

The objective of this study was to report the CT appearances of radiation-induced jaw osteosarcomas (RIJOS) following therapeutic irradiation. The CT studies of 7 subjects with RIJOS were reviewed retrospectively. RIJOS developed at 3 to 14 years following radiotherapy. Four patients had tumors in the maxilla and 3 in the mandible. Five tumors were osteoblastic, with 1 osteolytic and 1 mixed lesions. Osteoid tumor matrix mineralization was identified in 6 subjects. Periosteal reaction was demonstrated in 6 cases. All subjects showed a soft tissue extension component beyond the area of bone destruction. CT is a useful tool to identify RIJOS and plays an important role in preoperative assessment of the extent of the tumor.

Immunological state of reaction and healing of osteotomy (author's transl)

The influence of immune reaction on rats - achieved through C. F. A. - on the healing of incomplete osteotomy of the femur was experimentally examined. It was found that the production of immune reaction, manifested by the appearance of polyarthritis, leads in a great percentage (60% of the animals) in extensive bone destruction in the vicinity of the osteotomy. The results were examined clinically, radiologically and histologically. The type of reacton in the area of bone destruction was of immunological origin (histological examination).

Plasmablastic lymphoma of visceral cranium, cervix and thorax in an HIV-negative woman

Dear Editor, We would like to report a case of aggressive plasmablastic lymphoma (PBL) in an HIV-negative individual, characterised by a unique combination of unusual clinical and immunophenotypic features. A 67-year-old woman presented with a 20-day history of a painless mass lesion in the left supraclavicular fossa. She was also complaining of blurred vision and a continuous mild retrosternal pain. She denied fever, night sweats or weight loss. Her past medical history was negative for diseases or treatments associated with immunodeficiency. On physical examination, she had diplopia on upward gaze. A painless firm mass 3×4 cm in size was palpated in the left supraclavicular fossa. There was no peripheral lymphadenopathy, organomegaly or other remarkable findings. Laboratory investigations showed a normal full blood count and serum biochemical profile, including normal lactate dehydrogenase levels. No paraprotein was present on serum and urine electrophoresis. Enzyme-linked immunosorbent assay testing for HIV antibodies was negative. Computerised tomography (CT) imaging studies revealed a mass with soft tissue density occupying the left sphenoid sinus and infiltrating the ethmoid sinus and ipsilateral concha with associated areas of bone destruction. The mass was extending to the left orbit with thickening of the left inferior rectus muscle. There was also an evidence of tumour invasion of the left maxillary antrum and mandibular ramus. Furthermore, soft tissue masses compatible with multiple lymph node enlargement and block formation were present in the inferior frontolateral cervical region with extension to the anterior upper mediastinum. CT imaging of abdomen was negative for lymphadenopathy or organomegaly. A bone marrow biopsy was negative for neoplastic invasion. Biopsy of the cervical mass revealed a neoplasm causing complete effacement of nodal architecture and extending to the adjacent adipose tissue. The neoplastic tissue consisted of diffusely growing largeand medium-sized cells with polymorphic nuclei, frequent mitoses and moderate-to-large amount of eosinophilic or amphiphilic cytoplasm (Fig. 2a). Immunohistochemical investigation using markers of epithelial (Ker HMW, Ker LMW, Ker7, Ker20, EMA, Cam 5-2), lymphoid (CD3, CD20, CD45RO, CD45, CD30, CD21, CD79a, CD8, CD56, CD138, kappa and lambda chains, immunoglobulins), mesenchymal (S-100, vimentin, actin, desmin, CD31, CD34, GFAP (glial fibrillary acidic protein)), histiocytic (CD68), melanocytic (HMB-45) differentiation and various others (Bcl-2, CD99, neuron-specific enolase [NSE]) revealed only a strong expression of vimentin and a small percentage of cells with moderate positivity for NSE. Blind biopsies from the nasopharynx indicated only nonspecific immunologic stimulation of the lymphoid tissue. Ann Hematol (2007) 86:615–618 DOI 10.1007/s00277-007-0280-z

Osteoclastoma of temporal bone

A 20 year male presented with a gradually increasing painless swelling at right temporal region with progressive hearing loss conductive in type. On plain X-ray-a wide radio translucent area of bone destruction was noted. The mass was excised as much as possible via post-auricular incision extending antiriorly toward the zygomatic root.Histopathological examination showed the features suggestive of osteoclastoma. Post-operative radiation was administered to deal with the remaining mass there was no recurrence of growth even.

Keep your eyes on the ribs: the spectrum of normal variants and diseases that involve the ribs.

A variety of normal variants or pathologic conditions of the ribs may be overlooked at chest radiography if the ribs are not evaluated carefully. Rib lesions may simulate pulmonary disease as well. Normal rib variants include cervical, intrathoracic, and pelvic ribs; forked rib; fusion and bridging; and pseudarthrosis of the first rib. Trauma-related lesions are common and usually occur in isolation but can alert the radiologist to other injuries. Metastases may appear as vague areas of increased opacity overlying the lung if seen en face and typically have a smooth interface with the lung on oblique images. Chondroid lesions nearly always arise at or near the anterior end of the rib. Osteochondroma (exostosis) typically manifests as a deformity or expansion of the rib with calcification of the cartilaginous cap. Acute rib infections are seen as focal areas of bone destruction, whereas chronic infections may manifest as periosteal reaction or a bone sequestrum. Inferior rib notching may be seen in a wide variety of pathologic conditions. Rib abnormalities may also be seen in fibrous dysplasia, Langerhans cell histiocytosis, Paget disease, and various hemoglobinopathies. In most cases, radiography is sufficient for the identification and diagnosis of normal variants and pathologic conditions of the ribs.

Bone scintigraphy in plasma cell myeloma

A retrospective study of histologically proven cases of plasma cell myeloma during a 13-year period showed that bone scintigraphy was performed in 15 patients. With respect to radiologically shown areas of bone destruction, scanning revealed an increased (44%), normal (48%), or decreased (8%) radionuclide uptake. Abnormal scintigraphic findings were predominantly found in the axial parts of the skeleton. Abnormal isotope accumulations in the ossei occurred more often than normal uptake in symptomatic patients.

Thoracic involvement from osteosarcoma: typical and atypical CT manifestations.

O steogenic sarcoma (osteosarcoma) is characterized by malignant deposition of osteoid with varied amounts of mineralization, cartilage, and fibrous tissue. The resulting typical radiographic appearance is that of permeative or irregular areas of bone destruction with adjacent bone formation containing varying degrees of mineralization. Osteosarcoma metastasizes predominantly through the hematogenous route, most frequently to the lungs. Ossification of metastases due to mineralization of an osteoid matrix is not rare [1]. CT is regarded as the imaging technique of choice for detecting pulmonary metastasis in osteosarcoma [1-3]. Scmtigraphy may also be of value, particularly for osteoblastic osteosarcomas [1, 2]. We have collected several CT scans of patients with metastatic osteosarcomatous lesions in uncommon locations, including the mediastinum, hilum, pleura, chest wall, and heart. The purpose of this essay is to illustrate and discuss common and uncommon thoracic sites of metastatic osteosarcoma, with emphasis on unusual manifestations of metastasis.

POSTRADIATION SARCOMA OF BONE

A 58-year-old woman was examined because of increasing low back and left buttock pain of 2 months' duration. Her discomfort occurred at night and was progressive. The pain was not responsive to anti-inflammatory medications and was not related to activity. The patient's medical history was significant for successful treatment of an adenocarcinoma of the colon 17 years previously. In addition to surgical treatment, she had received a course of adjuvant external beam radiation. The radiation was delivered over a 5 ½-week period through parallel opposed fields. The estimated midline dose was 40 Gy centered over the left iliac fossa. The source of radiation was cobalt 60. A plain radiograph of the pelvis suggested an area of bone destruction in the ileum near the left sacroiliac joint (Fig 1A). A computed tomography (CT) scan demonstrated cortical destruction of the left iliac wing and an associated soft tissue mass (Fig 1B). A staging evaluation revealed lung metastasis, indicating that the patient had Stage III disease.1 A diagnosis of high-grade fibroblastic osteosarcoma was made after biopsy of the lesion in the left iliac wing (Fig 2). The patient died of the lesion 1 month after presentation.

Gd-DTPA Enhanced MR for Detecting Intracranial Extension of Sinonasal Malignancies

Magnetic resonance imaging is frequently used for evaluating the extent of malignant tumor in the paranasal sinuses and nasal fossa. Detection of the intracranial extension of a tumor is important in the initial staging of disease. The epidural component of a sinonasal tumor frequently displays signal intensity at or near that of the adjacent brain on standard T1- and T2-weighted scanning sequences. In six of eight malignant sinonasal tumors with intracranial involvement, gadopentetate dimeglumine (Gd-DTPA) enhanced MR was significantly better than the noncontrast scans for demonstrating the intracranial extension. This finding is in contradistinction to the superiority of unenhanced T2-weighted scans for determining the extent of disease within the sinonasal region itself. Tangential Gd-DTPA MR scanning of the skull base compensates for the difficulty of recognizing areas of bone destruction on noncontrast images. Postcontrast sequences should be added to the scanning protocol for sinonasal lesions near the skull base.

Malignant fibrous histiocytoma of jaws. A clinicopathologic study of 11 cases.

Malignant fibrous histiocytoma (MFH) of the jaws is a highly malignant tumor that recurs, metastasizes, and usually causes death despite aggressive surgical therapy. This clinicopathologic review looks at five patients with MFH of the maxilla and six with MFH of the mandible. Five male and six female patients ranged in age from 12 to 75 years (mean, 35.4 years). All patients had large lytic areas of bone destruction, often with soft tissue extension. Two cases were postirradiation sarcomas, one of the maxilla and the other of the mandible. All patients underwent surgery and eight patients received chemotherapy when disease recurred locally or metastasized. Seven patients had local recurrences 3 to 13 months following surgery, and six patients had distant metastases. Of the 11 patients, 7 died of their disease, 1 died of unknown causes, and another with extensive local disease was lost to follow-up after 1.7 years. Two patients with recurrent disease are alive at 18 and 27 months postoperatively.