Skeletal Muscle - Cyst



comment:
Epithelium-lined cysts can develop in skeletal muscle ( Figure 1



Parasitic cysts are sometimes present within skeletal muscle. While Sarcocystis muris does infect skeletal muscle in rats and mice, it is not common in well-managed rodent colonies and is generally not associated with accompanying inflammation. If accompanying lesions are present, they are primarily degenerative in nature.
recommendation:
While skeletal muscle cysts are often incidental lesions, their presence should be recorded. A severity grade does not need to be assigned. Accompanying myopathic changes do not need to be diagnosed separately unless warranted by severity. The nature of the lining cells, presence and nature of luminal contents, and regional effects on adjacent skeletal muscle fibers should be addressed in the narrative.references:
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Greaves P. 2007. Musculoskeletal system. In: Histopathology of Preclinical Toxicity Studies, 3rd ed. Elsevier, Oxford, 160-214.
Greaves P, Chouinard L, Ernst H, Mecklenburg L, Pruimboom-Brees IM, Rinke M, Rittinghausen S, Thibault S, von Erichsen J, Yoshida T. 2013. Proliferative and non-proliferative lesions of the rat and mouse soft tissue, skeletal muscle, and mesothelium. J Toxicol Pathol 26(3 suppl):1S-26S. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/25035576
McDonald MM, Hamilton BF. 1990. Bones, joints, and synovia. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman G, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 193-207.
Percy DH, Barthold SW. 2007. Mouse. In: Pathology of Laboratory Rodents and Rabbits, 3rd ed. Blackwell, Ames, IA, 88-89.
Vahle JL, Leininger JR, Long PH, Hall DG, Ernst H. 2013. Bone, muscle, and tooth. In: Toxicologic Pathology: Nonclinical Safety Assessment (Sahota PS, Popp JA, Hardisty JF, Gopinath C, eds). CRC Press, Boca Raton, FL, 561-587.
Yang S-W, Teng H-P, Tarng Y-W, Wong C-Y. 2007. Intramuscular ganglion cyst of the quadriceps muscle: Report of a case. Mid Taiwan J Med 7:193-197.
Web page last updated on: March 13, 2015