A 36-year-old woman presented with muscle hypertrophy (particularly of the calves) since puberty, occasional muscle cramps, a musculine habitus, and a loss of subcutaneous fat on limbs and trunk sparing her face, neck, and vulva. Multiple lipomas were found on her trunk, and acanthosis nigricans on her neck. Laboratory testing revealed hyperlipidemia and pathological glucose tolerance with hyperinsulinemia. Physical and laboratory findings are consistent with Köbberling-Dunnigan syndrome, a rare inherited form of lipoatrophy. The patient's mother had the same body habitus and insulin-dependent diabetes mellitus. These cases suggest that partial lipodystrophy also affects muscle and is a cause of genuine muscular hypertrophy.© 1996 John Wiley & Sons, Inc.