Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This article focuses on major clinical and imaging features that are of practical interest in the diagnosis and management of osteosarcoma, a malignant tumor arising from the osteogenic matrix. The current histologic classification of this tumor is also reported. Different types of osteosarcoma are described, each of them with a definite clinical and radiographic pattern. Conventional radiography is the keystone to diagnosis because it allows analysis of the patterns relevant to the different lesions (location, site, bone destruction, periostal reaction, soft tissue masses). The most common type of osteosarcoma is defined classic or conventional high grade (75%) and it typically involves the medullary cavity. Radiographically, it may be predominantly osteosclerotic or osteolytic, but more frequently it has a mixed (osteoslerotic/osteolytic) pattern. The teleangiectatic osteosarcoma is an aggressive form (5%) characterized by marked vascularization with large blood-filled cystic cavities; its typical radiographic pattern is purely osteolytic. Juxtacortical osteosarcoma (8-10%) indicates a group of osteosarcomas apparently arising on bone surface. The most common type is parosteal osteosarcoma which affects older subjects and has a better prognosis than the classic type. Radiography shows a heavily ossified mass with a broad base attached to the underlying cortex. CT and MRI are useful in the differential diagnosis of osteosarcoma and myositis ossificans or osteocondroma. Rare types of osteosarcoma include the periosteal and high-grade surface variants, as well as secondary and multifocal osteosarcoma (osteosarcomatosis). CT and MRI are the imaging procedures of choice in locoregional staging (intraosseous and extraosseous spread, skip metastases, growth plate and articular involvement). CT of the chest is a useful tool for detecting lung metastases. Also MRI has a role in monitoring the response to chemotherapy and in detecting recurrence. It permits a more accurate study of the tumor volume than other imaging techniques and clinical examination. MRI becomes even more useful when paramagnetic contrast agents are administered because dynamic MRI with contrast enhancement help differentiate postchemotherapy changes from viable tumor--the latter enhancing rapidly and the former slowly. Thus, dynamic MRI allows a precise mapping of any residual tumor activity.
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PMID:Malignant tumors of the osteogenic matrix. 965 9

We report a case of a histologically well differentiated, grade I, parosteal osteosarcoma of the distal ulna. The tumour's radiological and histological features are described, and the patient's course after wide en-bloc resection is detailed. Parosteal osteosarcoma is a rare low-grade malignant neoplasm. It belongs to the group of the osteosarcomas originating from the surface of the bone, representing a distinct tumour entity within this group, with defined histological and radiological features. We describe the radiological and histological characteristics of parosteal osteosarcoma and, based upon these features, present its classification. The differential diagnosis, including parosteal osteoma, myositis ossificans and osteochondroma, is also discussed. Finally, therapy and prognosis are outlined in accordance with the current literature. Wide en-bloc resection represents the mainstay of therapy offering an excellent prognosis with a 5-year survival rate of more than 90%. Incomplete resection, on the other hand, increases the risk of recurrence and dedifferentiation of the tumour. Dedifferentiation induces tumour spread and is associated with a poor prognosis equivalent to conventional osteosarcoma.
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PMID:Parosteal osteosarcoma of the distal ulna. A rare tumour at a rare location: a case report. 1282 46

Parosteal osteosarcoma and low-grade central osteosarcoma are two types of low-grade osteosarcoma that show similar clinical behaviors, histological features, and genetic background (ie, amplified sequences of 12q13-15, including MDM2 and CDK4). Low-grade osteosarcoma is often confused with benign lesions, and ancillary techniques to enhance diagnostic accuracy have been awaited. This study explores the use of MDM2 and CDK4 immunohistochemistry for the histological diagnosis of low-grade osteosarcoma. We studied 23 cases of low-grade osteosarcoma from 21 patients (parosteal osteosarcoma (n=14), low-grade central osteosarcoma (n=9)) and 40 cases of benign histological mimics (myositis ossificans (n=11), fibrous dysplasia (n=14), osteochondroma (n=6), desmoplastic fibroma (n=1), florid reactive periostitis (n=4), Nora's lesion (n=3), and turret exostosis (n=1)). Low-grade osteosarcoma labeled for MDM2 in 16 cases (70%) and for CDK4 in 20 cases (87%). All low-grade osteosarcomas expressed one or both markers (100%), with 13 cases (57%) expressing both. Staining pattern was diffuse in most cases, and the majority expressed moderate or strong intensity for either antibody. MDM2/CDK4 immunostaining was shown irrespective of low-grade osteosarcoma histological subtype. In contrast, only 1 Nora's lesion out of the 40 miscellaneous benign processes showed immunoreactivity for MDM2 or CDK4. The combination of these two markers thus shows 100% sensitivity and 97.5% specificity for the diagnosis of low-grade osteosarcoma. MDM2 and CDK4 immunostains therefore reliably distinguish low-grade osteosarcoma from benign histological mimics, and their combination may serve as a useful adjunct in this difficult differential diagnosis.
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PMID:Immunohistochemical analysis of MDM2 and CDK4 distinguishes low-grade osteosarcoma from benign mimics. 2060 38