Sensory, motor, and autonomic neuropathy in patients with multiple symmetric lipomatosis.

Clinical evaluation of 33 male patients affected by multiple symmetric lipomatosis has revealed a previously unreported high prevalence of somatic and autonomic neuropathies. In 84% of the patients, clinical examination revealed signs or symptoms of neural disturbances, ranging from a vibratory sensory loss to severely incapacitating trophic ulcers or Charcot's arthropathy. Electrodiagnostic investigations demonstrated a significant reduction of motor and sensory conduction velocity in the peroneal and sural nerves. Morphometric studies of nerve and muscle biopsies from five patients with multiple symmetric lipomatosis revealed a significant reduction in myelinated fiber density (4435 +/- 593 fibers/mm2 in MSL vs 7660 +/- 800 in controls; p less than 0.05), a selective reduction in the large fibers of 7 to 10 micron in diameter, and signs of chronic denervation-reinnervation processes. Bedside tests for autonomic neuropathy were abnormal in 15 of 20 patients studied. Metabolic studies in these patients confirmed a significant increase in plasma high-density lipoprotein fractions consistent with the diagnosis of hyperalphalipoproteinemia, and a significant reduction in plasma low-density lipoprotein fractions (hypobetalipoproteinemia) associated with a marked enhancement of lipoprotein lipase activity in adipose tissue. Thus, a metabolic factor has to be considered in the pathogenesis of MSL neuropathy.