In addition to classic organ system involvement, Lyme disease may be characterized by myositis, liver and spleen involvement, and atypical cutaneous manifestations. Myositis is characteristically localized near an involved joint or localized neuropathy. Nuclear imaging with gallium-67 may be useful for detection. Myositis responds to treatment with intravenous or oral antibiotics. Patients with erythema migrans have been observed to have liver function test abnormalities in the absence of symptomatic hepatitis. Splenomegaly has been noted infrequently in patients with Lyme disease. Chronic cutaneous manifestations of Lyme disease--including erythema migrans, acrodermatitis chronica atrophicans, and lymphadenosis benigna cutis--have been observed more frequently in Europe than in the United States. It appears that they are caused primarily by the Borrelia afzelii genomic group of Borrelia burgdorferi, which has been found exclusively in Europe.