Multiple symmetric lipomatosis: clinical aspects and outcome in a long-term longitudinal study.

BACKGROUND: Multiple symmetric lipomatosis (MSL) is a rare disease characterized by the growth of uncapsulated masses of adipose tissue. MSL is associated with high ethanol intake and complicated by somatic and autonomic neuropathy and by the infiltration of the adipose tissue at the mediastinal level. To date, the disease is considered as slowly progressive, but long-term longitudinal data are still lacking. In this study, a long-term follow-up of a large series of MSL patients is presented. METHODS: We studied 31 patients with MSL (30 males and one female) first evaluated at our institution from 1973 to 1992. All patients were followed until 1998-1999 or until death, with a mean follow-up of 14.5+/-5.0 y (range 4-26 y). Both at baseline and during follow-up, the location and the size of the subcutaneous lipomatous fat depots, the presence and the extension of deeply localized lipomatous tissue, and the presence and the severity of both somatic and autonomic neuropathy were evaluated. RESULTS: Eight MSL patients died during follow-up (25.8% of patients). A sudden death was proved to be the cause of death in three patients. All these three patients had severe autonomic neuropathy and none had coronary disease, acute myocardial infarction or other cardiac abnormalities. No signs or symptoms of coronary heart disease were present in the whole series. In addition to this high fatality rate, a substantial morbidity related to the occupation of the mediastinal space by the lipomatus tissue and to somatic neuropathy was also observed. CONCLUSIONS: MSL is associated with a significant morbidity and mortality. Therefore, the definition of 'benign symmetric lipomatosis', still adopted by several authors, cannot be justified.

Multiple symmetric lipomatosis: evidence for mitochondrial dysfunction.

OBJECTIVES: : To assess the presence of mitochondria! dysfunction in 18 patients with multiple symmetric lipomatosis (MSL). METHODS: : Electromyography and nerve conduction study were performed in 15 patients with MSL and autonomic tests in 14. Nerve biopsy was done in four patients and muscle biopsy in six. Mitochondrial enzyme activities were measured in six muscle biopsies. We investigated myoclonic epilepsy ragged red fibers (MERRF) point mutation and multiple deletions in mtDNA with PCR, enzyme restriction digestion, and Southern blot analysis in lymphocyte DNA, or in muscle DNA when available. RESULTS: : Clinical or electrophysiological signs of polyneuropathy were found in 12 patients. Peroneal nerve biopsy showed decreased myelinated fibers. In muscle biopsies there were hyporeactive areas and subsar-colemmal rims of mitochondria. Respiratory chain enzymes levels showed a significant decrease of cyto-chrome-c oxidase (COX), succinic dehydrogenase (SDH), and citrate synthetase activity. Lymphocyte mtDNA showed the MERRF point-mutation in only one patient with MSL. CONCLUSIONS: : The mitochondrial dysfunction in MSL seems to be consistent with a reduced number of mitochondria and reduced mitochondrial enzyme activities; this could represent the pathogenetic basis of lipoma formation, as well as of other multisystemic clinical manifestations.