Proliferative Myositis: Difference between revisions
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== Associated Co-morbidities == | == Associated Co-morbidities == | ||
No associated co-morbidities have been reported. | |||
== Medications == | == Medications == |
Revision as of 05:04, 6 April 2011
Original Editors - Billie Rehberg from Bellarmine University's Pathophysiology of Complex Patient Problems project.
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Definition/Description [edit | edit source]
Proliferative myositis (PM) is a benign tumor which grows in skeletal muscle[1]. It is usually 3-4 cm in diameter[2], and is often mistaken for sarcomas (especially rhabdomyosarcoma)[3]. The tumor is formed by ganglion-like cells, fibroblasts, and myofibroblasts which increase the spaces between muscle fibers[2]. While etiology is unknown, it may result from injury to the muscle, fascia, or vasculature (resulting in ischemia) of the associated area[4]. PM generally presents in the upper extremity or trunk regions[2]. Median age of onset is 50 years[5], with rare cases reported in children[2]. [Photo: PM of the SCM muscle[1]]
Prevalence
[edit | edit source]
According to an article written by Fauser et. al in 2008, approximately 100 cases of PM had been published in the literature[1]. According to Jassar and Kumar (2005), approximately 1000 cases have been reported[6].
Characteristics/Clinical Presentation[1][6] [edit | edit source]
- Rapidly enlarging, solid tumor within skeletal muscle
- Localized inflammation
- No lymph node enlargement
- No significant laboratory results
- Localized pain
[Photo: Computerized Tomography of PM of the SCM muscle[1]]
Associated Co-morbidities[edit | edit source]
No associated co-morbidities have been reported.
Medications[edit | edit source]
add text here
Diagnostic Tests/Lab Tests/Lab Values[edit | edit source]
Proliferative Myositis is diagnosed based on biopsy[1]. The following list, taken directly from the Stanford University School of Medicine page on PM, are histologic and immunologic characteristics of PM which are used in its diagnosis:
o Relatively normal muscle fibers separated by expanded myxoid connective tissue
o Produces distinctive checkerboard pattern
o No evidence of muscle damage
o No sarcolemmal proliferation
o No multinucleation
o No nuclear enlargement
o No necrosis
o Connective tissue space between fibers contains reactive cells resembling those seen in nodular fasciitis and proliferative fasciitis
o Spindled and stellate fibroblasts and myofibroblasts
o Vesicular nuclei
o No cytologic atypia
o Actin positive
o CD68 variable
o S100, desmin negative
o Ganglion-like cells
o Characteristic feature of this process
o Large round regular nuclei
o Occasional binucleate and trinucleate cells may be seen
o Prominent nucleoli
o Dispersed chromatin
o Basophilic to amphophilic cytoplasm
o May be clustered and may mold each other
o Factor XIIIa positive
o Actin, CD68 negative to focal/weak
o Desmin, keratin, S100, neuron specific enolase negative
o Mitotic figures frequent
o No atypical mitotic figures [2]
Etiology/Causes[edit | edit source]
While etiology is unknown, PM may result from injury to the muscle, fascia, or vasculature (resulting in ischemia) of the associated area[4].
Systemic Involvement[edit | edit source]
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Medical Management (current best evidence)[edit | edit source]
Proliferative Myositis is a self-limiting pathology, meaning that the growth of the tumor will eventually stop. While spontaneous resolution of the tumor has been reported[1], surgical excision is the only treatment and recurrence following excision is rare[2].
Physical Therapy Management (current best evidence)[edit | edit source]
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Alternative/Holistic Management (current best evidence)[edit | edit source]
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Differential Diagnosis[5][3][2][edit | edit source]
- Myositis Ossificans
- Neoplasms (especially rhabdomyosarcomas)
- Proliferative fasciitis
- Nodular fasciitis
- Fibromatosis
- Ganglioneuroblastoma or ganglioneuroma
Case Reports/ Case Studies[edit | edit source]
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Resources
[edit | edit source]
add appropriate resources here
Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
see adding references tutorial.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Fauser C, Nahrig J, Niedermeyer H, Arnold W. Proliferative myositis: a rare pseudomalignant tumor of the head and neck. Archives of Otolaryngology - Head & Neck Surgery [serial on the Internet]. (2008, Apr), [cited March 16, 2011]; 134(4): 437-440. Available from: CINAHL with Full Text.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Stanford University. Proliferative Myositis. Available at http://surgpathcriteria.stanford.edu/softfib/proliferative_myositis/printable.html. Accessed April 4, 2011
- ↑ 3.0 3.1 Meis J, Enzinger F. Proliferative fasciitis and myositis of childhood. The American Journal Of Surgical Pathology [serial on the Internet]. (1992, Apr), [cited March 16, 2011]; 16(4): 364-372. Available from: MEDLINE.
- ↑ 4.0 4.1 Dent C, DeBoom G, Hamlin M. Proliferative myositis of the head and neck. Report of a case and review of the literature. Oral Surgery, Oral Medicine, And Oral Pathology [serial on the Internet]. (1994, Sep), [cited March 16, 2011]; 78(3): 354-358. Available from: MEDLINE.
- ↑ 5.0 5.1 Mulier S, Stas M, Delabie J, Lateur L, Gysen M, De Wever I, et al. Proliferative myositis in a child. Skeletal Radiology [serial on the Internet]. (1999, Dec), [cited March 16, 2011]; 28(12): 703-709. Available from: MEDLINE.
- ↑ 6.0 6.1 Jassar A, Kumar V. Proliferative myositis--a case report. Indian Journal Of Pathology & Microbiology [serial online]. January 2005;48(1):33-35. Available from: MEDLINE, Ipswich, MA. Accessed April 5, 2011.