Histology of HIV-associated inflammatory myopathies. (A–C) HIV-polymyositis (HIV-PM) cases showed endomysial lymphocytic infiltrates but no rimmed vacuoles or chronic myopathic features (A, representative image from biopsy #9a). The majority of HIV-inclusion body myositis (HIV-IBM) cases demonstrated classic features of sporadic IBM including rimmed vacuoles, endomysial fibrosis, and significant fiber-size variation (B, representative image from biopsy #12). A minority (3 of 14) of HIV-IBM cases showed pathognomonic rimmed vacuoles but lacked endomysial fibrosis or prominent fiber-size variation (C, representative image from biopsy #2). Arrowheads mark fibers with rimmed vacuoles. Scale bar, 20 µm.