[Chorea mollis, a rare variant of chorea minor].

A 15-year-old boy was admitted at age 10 because of muscle weakness, choreatic involuntary movements, and a profound hypotonia. He was diagnosed as having chorea mollis, a rare variant of Sydenham's chorea. He made a full recovery and received prophylaxis with monthly injections of benzathinebenzyl penicillin for the next 5 years. Six months after discontinuation of the prophylaxis he had a recurrence. The choreatic movements were successfully treated with haloperidol. However, a hypotonia and mild psychiatric symptoms still persist one year later. The clinical course, observed in our patient, is in concordance with the results of recent studies, reporting, that a number of patients with Sydenham's chorea may be left with mild to moderate neurologic and psychiatric sequelae.