We report on two patients with an asymmetrical expansion of fat tissue. At computed tomography, lipomatous tissue proved to be superficially located in one patient and both subcutaneously and deeply located in the second. Signs and symptoms of a peripheral neuropathy were observed in both patients, who were otherwise asymptomatic. The lipolytic activity in post-heparin plasma was normal in both patients. The fat cell size of lipomatous tissue, obtained in one patient by percutaneous needle biopsy, was higher than that of contralateral, uninvolved adipose tissue. The adipose tissue lipoprotein lipase activity in lipomatous tissue was higher than that in normal tissue. High density lipoprotein (HDL), HDL2 and HDL3 cholesterol values were elevated in both patients but not exceeding 1 standard deviation the values of age and sex matched controls. Isoprenaline-stimulated lipid mobilization was similar in lipomatous and in control tissue.