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

Eleven cases of proliferative fasciitis and myositis in children, ages 2.5 months to 13 years, are presented. Eight lesions averaging 2.3 cm in size occurred in the extremities, two in the head and neck region and one on the chest wall. Like proliferative fasciitis and myositis in adults, these lesions consisted of admixtures of large polygonal to spindled, ganglion-cell-like fibroblasts with vesicular nuclei and prominent inclusion-like nucleoli. Seven of 11 lesions were initially diagnosed as sarcomas, most commonly rhabdomyosarcoma. Four patients were treated by wide excision (three with regional lymphadenectomy), three received chemotherapy, and one was given radiation therapy. There were some histologic differences from adult-type proliferative fasciitis and myositis. The childhood lesions were generally well circumscribed, lobulated, extremely cellular with less collagen production, and often associated with acute inflammation and microscopic foci of necrosis. Immunohistochemical comparison with adult proliferative fasciitis and myositis showed similar immuneprofiles; the ganglion-like cells stained for vimentin and actin and focally with KP1, suggesting myofibroblastic and histiocytic features. None of the lesions stained for keratin, desmin, or S-100 protein. Ultrastructural examination of two cases revealed cells with a constellation of fibroblastic, myofibroblastic, and histiocytic features. Follow-up of seven patients, averaging 58 months from diagnosis, confirmed that all are alive and well. Recognition of this cellular variant of proliferative fasciitis and myositis is important to prevent misdiagnosis as a sarcoma and unnecessary, excessive therapy.
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PMID:Proliferative fasciitis and myositis of childhood. 156 69

The authors assessed a panel of immunohistochemical stains against 109 pediatric solid tumors, primarily rhabdomyosarcomas, under the auspices of the Intergroup Rhabdomyosarcoma Study. Fresh tumor tissue received from participating organizations was divided into portions that were either frozen or fixed in formalin, alcohol, or B5. Immunostaining was performed by the avidin-biotin complex method using monoclonal antibodies to desmin, neurofilaments, vimentin, cytokeratin, and leukocyte common antigen on cryostat sections. Tissue was also embedded in paraffin and stained with antimuscle-specific actin (MSA) and polyclonal antibodies to desmin, creatine kinase M subunit (CKM), myoglobin, and neuron-specific enolase (NSE). Antidesmin staining of cryostat sections was the most sensitive indicator of rhabdomyosarcoma (58 of 62 specimens positive). Results with this reagent in alcohol-fixed and formalin-fixed tissue were similar (46 of 56 positive versus 43 of 56 positive, respectively) and comparable with results with anti-MSA in formalin-fixed tissue (43 of 55 positive). However, the proportion of cells stained by antidesmin was higher in alcohol-fixed tissue than in formalin-fixed tissue. Staining with antimyoglobin and anti-CKM was much less satisfactory, with positivity rates of 17 of 37 and 11 of 57, respectively, in formalin-fixed rhabdomyosarcomas. Immunostaining of muscle markers revealed evidence of myogenesis in six undifferentiated sarcomas and in two sarcomas with inadequate histologic study on hematoxylin-eosin-stained sections. However, positivity was also noticed in samples of fibromatosis, Wilms' tumor, ectomesenchyoma, peripheral primitive neuroectodermal tumor, renal rhabdoid tumor, myositis ossificans, malignant fibrous histiocytoma, and embryonal sarcoma of the liver. The authors conclude that combined use of antidesmin and anti-MSA enhances the diagnosis of childhood sarcomas, especially when employed with other techniques such as electron microscopic study.
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PMID:Immunohistochemical study of childhood rhabdomyosarcomas and related neoplasms. Results of an Intergroup Rhabdomyosarcoma study project. 171 May 39

Tumors are rare causes of knee symptoms in children but must be considered in the differential diagnosis of pediatric knee pain in order to avoid errors in treatment that could result in loss of limb or even life. Experience with 199 bone and soft-tissue tumors about the knee in children are reviewed. The majority of lesions were benign bone tumors (n = 101), with osteocartilaginous exostoses, nonossifying fibromas, and chondroblastomas predominating. Malignant bone tumors (n = 59) were less frequent, and osteosarcoma (n = 48) was by far the most common sarcoma. Soft-tissue lesions (n = 31) were much less frequent and included rhabdomyosarcoma, synovial sarcoma, fibrosarcoma, and desmoid tumors. A careful history, physical examination, and review of roentgenograms are essential to avoid errors in diagnosis. Malignant tumors require roentgenograms and laboratory studies in sequence to stage the patient. A properly performed biopsy established the diagnosis in most instances. Popliteal cysts, stress fractures, infection, myositis ossificans, histiocytosis, and other lesions can mimic tumors and delay correct diagnosis.
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PMID:Tumors about the knee in children. 218 35

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

A 7-week-old infant with sudden onset adduction deficit and proptosis is reported. The main differential diagnoses included orbital myositis, orbital cellulitis, capillary haemangioma and rhabdomyosarcoma. A CT scan revealed a postseptal cellulitis-like picture with thickening of the medial rectus muscle. He was given a course of antibiotics, withholding steroids and biopsy. His condition resolved completely on high-dose antibiotics alone. To our knowledge this is the youngest patient with infectious orbital myositis and postseptal cellulitis described in the literature. The clinical course emphasizes the importance of administering sufficiently high doses of antibiotics.
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PMID:Acute adduction deficit in a 7-week-old infant. 1266 Aug 49

Orbital inflammatory disease (OID) broadly describes a variety of pathologic processes and clinical presentations. OID may be idiopathic or may be secondary to a systemic inflammatory disease, retained foreign body, or infectious disease. OID includes the spectrum of bacterial or fungal infections, diffuse inflammation of multiple tissues (e.g., sclerosing orbititis or diffuse anterior OID), and preferential involvement of specific orbital structures (e.g., orbital myositis or optic perineuritis). Mimics of OID include congenital orbital mass lesions or orbital neoplastic disease such as lymphoma or rhabdomyosarcoma. The ultimate diagnosis and treatment plan relies on a careful history and detailed clinical examination followed by the judicious use of ancillary diagnostic testing and a comprehensive treatment plan. The purpose of this review is to provide an overview of the spectrum of diseases known as OID, with emphasis on specific diagnostic challenges in the evaluation and management of patients with idiopathic OID.
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PMID:Diagnostic dilemmas in orbital inflammatory disease. 1285 23

Idiopathic inflammatory orbital myosites represent 10% of the orbital pseudotumors and 8% of the orbital pathologic processes in children. They are rarely described although they raise real diagnostic problems. The authors report the case of a 10-year old little girl who presented sudden proptosis. The clinical and radiological work up and the therapeutic test with corticosteroids were in favor of an inflammatory orbital myositis. The authors remind the clinical, radiological, and therapeutical aspects of this entity that remains very unfrequent in children and needs to be differenciated from rhabdomyosarcoma.
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PMID:[Orbital idiopathic inflammatory orbital myositis in a child: case report ]. 1870 Apr 52

This article discusses the role of MR imaging in the evaluation of musculoskeletal soft tissue masses, reviewing limitations in its ability to establish tissue diagnosis and its critical role in determining lesion extent. It also reviews benign soft tissue masses, such as fibrous lesions, popliteal cysts, lipomatous lesions, and neurofibromatous tumors. Reactive entities, such as abscess, myositis ossificans, and hemangioma, are discussed. Differentiation between high- and low-flow vascular and lymphatic anomalies is reviewed. The article concludes with a discussion of the uncommon malignant musculoskeletal soft tissue tumors, focusing on infantile fibrosarcoma, rhabdomyosarcoma, synovial sarcoma, and granulocytic sarcoma.
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PMID:MR imaging of soft tissue masses in children. 1952 98

Enterovirus 71 (EV71) infections can usually cause epidemic hand, foot, and mouth disease (HFMD), and occasionally lead to aseptic meningitis, encephalitis, and polio-like illness. Skeletal muscles have been thought to be crucial for the pathogenesis of EV71-related diseases. However, little is known about the virulence of mouse muscle-adapted EV71. The EV71 0805 were subjected to four passages in the mouse muscle to generate a mouse-adapted EV71 strain of 0805a. In comparison with the parental EV71 0805, the mouse muscle-adapted EV71 0805a displayed stronger cytotoxicity against Rhabdomyosarcoma (RD) cells and more efficient replication in RD cells. Furthermore, infection with the EV71 0805a significantly inhibited the gain of body weight, accompanied by increased muscle virus load and multiple tissue distribution in the infected mouse. Histological examinations indicated that infection with the EV71 0805 did not cause obvious pathogenic lesions in mice, while infection with the muscle-adapted 0805a resulted in severe necrotizing myositis in the skeletal and cardio muscles, and intestinitis in mice on day 5 post infection. Further analysis revealed many mutations in different regions of the genome of mouse muscle-adapted virus. Collectively, these data demonstrated the mouse muscle-adapted EV71 0805a with increased virulence in mice.
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PMID:A mouse muscle-adapted enterovirus 71 strain with increased virulence in mice. 2161 64