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Masticatory Muscle Myositis (view source)
Revision as of 16:15, 28 October 2014
, 16:15, 28 October 2014no edit summary
(MMM)
==Overview==
Masticatory muscle myositis (MMM) occurs in dogs and tends to affect the [[Mastication#Jaw Closing Muscles|masseter]] and [[Cheeks|temporalis]] muscles. Autoantibodies selectively attack the muscle of mastication, which contain type IIM fibres. MMM can be classified as either acute or chronic:
*'''Acute stage''': Eosinophilic myositis with extremely swollen, painful, hard masticatory muscles.
*'''Chronic stage''': Atrophic myositis where atrophy may occur without previous acute stage.
*Acute stage = eosinophilic myositis
*Chronic stage = atrophic myositis
Grossly MMM is normally bilateral, but not necessarily symmetrical.
[[Category:Muscles - Inflammatory Pathology]]
==Histology==
'''Acute lesions''':
*Mainly eosinophilic infiltrate, few lymphocytes, [[Monocytes|monocytes]] and plasma cells.
*In recurrent disease plasma cells predominate.
*[[Muscle Necrosis|Necrotic]] myofibres, [[Muscle Atrophy|atrophy]] and attempted [[Muscle Regeneration|regeneration]].
'''Chronic lesions''':
*[[Muscle Atrophy|Atrophy]] predominates.
*Fasciculi are shrunken.
*Condensation of stroma leading to an enlarged endomysium.
*Focal plasma cell and lymphocyte infiltration.
[[Category:Immune-Mediated Myositis]]
[[Category:To Do - Musculoskeletal]]
[[Category:Other Oral Conditions]]