Muscular dystrophies can show clinical and muscle biopsy features that mimic or overlap the changes seen in a primary myositis, particularly in the early stages of disease or when the clinical onset is abrupt. We present a child who was eventually diagnosed with limb girdle muscular dystrophy type 2I (LGMD2i). she presented with mild hip-girdle weakness and post-infectious myalgia. although her clinical symptoms favoured a muscular dystrophy, her muscle biopsy showed inflammatory infiltrates within muscle fibres and around blood vessels that were more typical of juvenile polymyositis. additional immunocytochemical antibody tests and genetic sequencing were key to obtaining an accurate diagnosis and avoiding immunosuppressant therapy.