Chloroquine-induced cytosomes with curvilinear profiles in muscle.

A patient with systemic lupus erythematosus (SLE) was treated with chloroquine therapy for four years after the onset of her illness. Nine years after cessation of chloroquine, muscle weakness developed as part of the SLE. Four muscle biopsies performed for diagnostic purposes revealed varying degrees of inflammatory change as well as distinctive cytosomes with curvilinear profiles (CCPs). These CCPs were identical to those reported in Batten disease, a degenerative disorder of children which has a clinical course different from SLE. The CCPs seen in this case of SLE are thought to result from the effect of chloroquine on membrane systems within muscle cells. This report calls attention to the fact that CCPs are not unique to Batten disease bu may also occur in muscle of SLE patients treated with chloroquine.