Extensive inflammatory reaction in facioscapulohumeral muscular dystrophy

Abstract

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disorder that predominantly affects the facial and scapular stabilizer muscles. It is considered a relatively benign disease, but its clinical spectrum is highly variable. 1 In muscle histopathology, most FSHD patients show nonspecific dystrophic features, but some patients may show prominent inflammatory changes that can lead to a misdiagnosis of polymyositis. 2 Although some studies have analyzed inflammatory cellular subsets in FSHD with inflammation, 2-5 the role and significance of these cellular infiltrates in FSHD remain unclear. Here we describe the clinical, pathologic, and molecular genetic findings for a patient with FSHD in whom a muscle biopsy revealed unusually extensive inflammatory reactions. CASE A 16-year-old girl visited us with generalized muscle weakness. Her weakness started at 11 years of age when she began to experience difficulties running and raising her arms. She denied any preceding febrile illness or trauma at that time. Her weakness slowly worsened, In facioscapulohumeral muscular dystrophy (FSHD), prominent inflammatory cellular infiltrates mimicking inflammatory myopathies are often observed in muscle biopsies. We report extensive inflammatory changes in a 16-year-old girl who was genetically confirmed as to have FSHD. Immunohistochemical staining revealed that this could be clearly distinguished from in-flammatory myopathies, both in terms of cell subsets and the expression of antigenic targets. Our observations strongly suggest that the inflammatory cellular infiltrates in FSHD differ from those observed in inflammatory myopathies.