Immunophenotyping in muscle biopsies with inflammation: The dysferlinopathy example

Inflammation in muscle biopsies frequently leads to the diagnosis of myositis, particularly in isolated cases with no known family history. We describe a Yemenite Jewish patient with limb-girdle muscular dystrophy type 2B due to a mutation in the dysferlin gene. Repeated muscle biopsies six years apart demonstrated necrotizing myopathy accompanied by perivascular inflammatory infiltrates. An initial diagnosis of polymyositis led to unnecessary corticosteroid treatment. Detailed immunohistochemical phenotyping, including the use of major histocompatibility complex Class I antigen may aid in differentiating inflammatory from dysferlin-deficient dystrophic myopathy.