Membranous lipodystrophy is known as Nasu-Hakola disease. The main symptoms of membranous lipodystrophy are those of a progressive presenile dementia due to sclerosing leukoencephalopathy with skeletal polycystic lesions. There is no report detailing long-term follow-up of patients with membranous lipodystrophy. We present a 56-year-old woman with this disease who has not manifested any typical neuropsychiatric symptoms during the 16-year follow-up, and thus has had an unusually benign clinical course. The patient underwent curettage and bone grafts. Periodic examinations have been continued for 16 years from discharge. No recurrence of lesions or occurrence of new cystic lesions has been noted. Computerized tomography and magnetic resonance imaging of the brain revealed none of the abnormal change which are reported in this disease. Our findings suggest that some patients with this disease may be fortunate enough to follow a relatively benign clinical course.