Extensive inflammatory reaction in facioscapulohumeral muscular dystrophy

predominantly affects the facial and scapular stabilizer muscles. It is considered a relatively benign disease, but its clinical spectrum is highly variable. 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. Although some studies have analyzed inflammatory cellular subsets in FSHD with inflammation, 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.