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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aminoacyl-tRNA synthetases play a dual role in cell metabolism by synthesizing aminoacyl-tRNAs and an odd dinucleotide diadenosine-5', 5''-P1, P4-tetraphosphate which appears to be involved in DNA replication and the control of cell proliferation. This review is a synthesis of recent results on the structure, genetics, cell biology, physiology, role in neoplasia, and role in autoimmune myositis of the higher eukaryotic aminoacyl-tRNA synthetases.
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PMID:Higher eukaryotic aminoacyl-tRNA synthetases in physiologic and pathologic states. 353 43

The authors report a case of myositis ossificans localised in the abductor digiti minimi of the hand. This type of fast growing tumor can be confused with malignant tumors. The diagnosis between these different tumors is discussed. Surgical removal seems the best treatment.
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PMID:[Myositis ossificans of the hand: the problem of a pseudomalignant tumor]. 361 28

Increased signal on T2-weighted magnetic resonance (MR) images has been demonstrated in skeletal muscle adjacent to neoplasms. Clinical significance of this sign was evaluated by reviewing MR images of 50 patients with musculoskeletal disorders. Increased signal in adjacent muscle was present in 22 patients, including 13 of 25 with primary or secondary malignancies of the musculoskeletal system. Biopsy specimens from the affected area in 11 of these 13 patients revealed edema (n = 8) more often than tumor invasion (n = 3). Nine of 25 patients with nonneoplastic processes had increased signal intensity in skeletal muscle because of infection, myositis, or hematoma. In patients who have not undergone previous surgery or radiation therapy and are without an inflammatory mass, increased signal intensity may be a useful indicator of malignancy.
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PMID:Increased MR signal intensity in skeletal muscle adjacent to malignant tumors: pathologic correlation and clinical relevance. 378 72

Pseudoneoplastic tumors are considered as a clinicoanatomic entity with a characteristic macro- and microscopic pattern, obscure etiology and genesis. The dissection data have demonstrated the forms of pseudoneoplastic processes. Observations of the most rare pseudotumors, such as "inflammatory" pseudotumor and tumor-like myositis ossificans are presented. "Inflammatory" pseudotumors are characterized by the involvement of the immune system cells, increased fibrillogenesis, and intensive osteogenesis in the lungs and the stomach. Cases of pseudoneoplastic myositis ossificans combined with tissue malformation are given particular attention.
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PMID:[Pseudotumor processes in children ( according to material from the Filatov Children's Clinical Hospital)]. 382 24

A case is presented of a 10-year-old girl who had a benign osseous tumor of the temporalis muscle. The tumor appeared to be a variant of the so-called pseudomalignant osseous tumor of the soft tissues and could readily be distinguished from both osteogenic sarcoma and myositis ossificans.
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PMID:Pseudomalignant osseous tumor of the temporalis muscle. 386 77

Ocular inflammatory diseases and ocular adnexal lymphoid tumors have become less obscure and intimidating by virtue of our ability to study the infiltrates in these various diseases for their B-lymphocyte and T-lymphocyte composition. Comparisons are also possible between lymphocytic profiles in the peripheral blood and the precise composition of the in situ infiltrates within the ocular tissue themselves. The availability of monoclonal antibodies, which can determine T-lymphocytic subsets such as T-helper cells and T-suppressor/cytotoxic cells, natural killer cells, and monocytes-histiocytes, has provided a powerful technology for the delineation of the distinctive immune composition of the inflammatory infiltrates, as well as any possible disturbances in T-cell immunoregulation. B-lymphocytes produce immunoglobulins, which may be misdirected as autoantibodies in local or systemic autoimmune diseases. Immunoglobulin-mediated and therefore B-cell derived conditions include vasculitis, progressive cicatricial ocular pemphigoid, Mooren's corneal ulcer, scleritis, and hay fever and vernal conjunctivitis. Other diseases in which B-lymphocytes, their immunoglobulin products or immune complexes formed with presently unknown antigens are potentially at fault are chronic non-specific uveitis; iridocyclitis in Behcet's syndrome; Fuch's heterochromic syndrome, ankylosing spondylitis, and Reiter's syndrome; Graves' disease; and idiopathic inflammatory orbital pseudotumor and myositis. T-cells do not produce immunoglobins, but rather secrete lymphokines or interact directly with receptors or determinants on viruses or target tissues (eg. immunosurveillance against neoplasia); it is possible that some autoimmune diseases are the result of neo-antigens on the surfaces of host tissues that have been coded for by a cryptic inciting virus. T-cell diseases include phlyctenulosis graft rejections, graft versus host disease, and possibly sympathetic ophthalmia and temporal arteritis. Natural killer cells are involved in many of the same diseases as cytotoxic T-cells, except that the former require no period of sensitization (natural immunity), whereas cytotoxic T-cells must undergo an antigen-specific blast transformation (acquired immunity of the delayed hypersensitivity type). In many diseases in which B-cell derived auto-antibodies are at fault, there may be local tissue or systemic T-cell imbalances, with a reduction in T-suppressor cells and a relative augmentation in T-helper cells, thereby facilitating production of misdirected auto-antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:B- and T-lymphocytes in ocular disease. 623 70

Malignant fibrous histiocytoma of soft tissues (MFH), a mesenchymal tumor of varied morphologic patterns and cell types, sometimes contains bone and cartilage. Such bony and cartilaginous elements in a pleomorphic MFH may pose a difficult diagnostic challenge. An MFH with bone and cartilage can be distinguished from extraosseous osteogenic sarcoma and chondrosarcoma on the basis of qualitative and quantitative features of the osseous and chondroid elements. Five cases of soft tissue MFH containing bone and cartilage reported here showed: 1) that the bony and cartilaginous elements are mostly metaplastic and tend to be in the pseudo-capsule or fibrous septa of the tumor; and 2) that the bony elements may show a zoning pattern with peripheral maturation similar to myositis ossificans. In a single case, there was a small amount of "tumor osteoid." However, this was focal and lacked the diffuse and finely divided or ribbon-like pattern generally associated with osteogenic sarcoma. The probability that MFH with bone and cartilage is less aggressive than soft tissue osteogenic sarcoma or chondrosarcoma underscores the importance of accurate histologic diagnosis of these tumors.
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PMID:The significance of bone and cartilage formation in malignant fibrous histiocytoma of soft tissue. 627 50

The presence of bone and cartilage in some cases of malignant fibrous histiocytoma of the soft tissue as a microscopic finding has been reported previously but little note has been taken of the radiologic manifestations of these tumor elements. A series of five such cases with sufficient metaplastic osseous and cartilaginous elements to produce roentgenographic evidence of their presence is reported here. An additional two cases showed only histologic evidence of bone or cartilage formation. The reactive ossification tends to be peripheral in location, involving the pseudocapsule of the sarcoma or its fibrous septa. In three there was a zoning pattern with peripheral or polar orientation, strongly suggesting the diagnosis of myositis ossificans. The latter was the diagnosis considered radiologically in four of the five cases. Malignant fibrous histiocytoma with reactive bone and cartilage must be considered in the differential diagnosis of soft tissue masses with calcific densities, particularly when these occur in tumors of the extremities.
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PMID:Malignant fibrous histiocytoma of soft tissue with metaplastic bone and cartilage formation: a new radiologic sign. 628 19

A case of proliferative myositis of the masseter muscle in a 62-year-old woman is presented and pertinent literature is reviewed. This benign pseudosarcomatous proliferative lesion has not been previously reported in any of the muscles of mastication. Clinically the patient presented with pain and difficulty in opening of the mouth. On initial examination, a malignant salivary gland tumor was suspected. The proliferative myositis exhibits a disturbing microscopic appearance characterized by the presence of numerous hyperchromatic fibroblasts and oval or spindle-shaped giant cells which resemble malignant rhabdomyoblasts. These lesions have been often misdiagnosed as rhabdomyosarcoma and other types of sarcomas. Awareness of the microscopic characteristics of proliferative myositis and the possibility of its occurrence in the perioral soft tissues is important in avoiding misdiagnosis of this benign condition.
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PMID:Proliferative myositis of the masseter muscle. A case report and a review of the literature. 634 58

The value of new morphologic methods in the diagnosis of bone tumors is demonstrated in a number of cases. In round cell malignancies (Ewing's sarcoma, malignant lymphoma, neuroblastoma, and anaplastic plasmacytoma) diagnostic accuracy can be improved by electron microscopic and immunohistochemical techniques. New methods are also of value in differentiating the metastatic carcinoma from malignant bone primaries. Electron microscopy may show epithelial cell features (ie, gland structures, desmosomes, and tonofilaments), while immunohistologic investigation of the cytoskeleton may facilitate differentiation of epithelial cells (positive for prekeratin) from mesenchymal cells (positive for vimentin). In the differential diagnosis of typical bone tumors, however, such as osteosarcoma, chondrosarcoma, and malignant fibrous histiocytoma, the value of enzyme histochemical, electron microscopic, and immunohistochemical methods appears somewhat restricted: alkaline phosphatase activity may be increased in both chondrosarcoma and osteosarcoma; collagen type II, the cartilage-specific collagen, is found not only in chondrosarcoma but in osteosarcoma as well. Moreover, osteosarcomas may contain a considerable number of macrophages and histiocytes, and so this feature is worthless in distinguishing osteosarcoma from malignant fibrous histiocytoma. A new approach for appraising the malignancy of bone tumors may be through flow cytometric investigation of nuclear DNA content. Osteosarcomas reveal DNA aneuploidies in more than 80% of cases, with a large proportion of cells in the S phase. These features may prove valuable for discerning osteosarcoma from myositis ossificans. In contrast to typical giant cell tumor of bone, a rare case of malignant giant cell tumor showed aneuploid cell lines indicating the malignant nature of the tumor.
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PMID:New cytomorphologic methods in the diagnosis of bone tumors: possibilities and limitations. 660 Jan 11


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