Case of semicircular lipoatrophy: relation between its characteristic distribution and anatomical muscle structure.

Semicircular lipoatrophy is characterized by one or more partial, horizontal, band-like depressions, usually on the anterolateral thigh or thighs. We report the case of a 47-year-old woman who presented with a 1-month history of bilateral, parallel, symmetrical depressions on the anterolateral aspects of her thighs. She had been wearing a tight girdle, and the girdle's folds matched the cutaneous bands. Ultrasound examination of the affected areas showed that the muscle tensor fasciae latae became its tendon at this level, and the muscle rectus femoris originated at the same level in the deeper layer. Although semicircular lipoatrophy has a predisposition for the anterolateral aspect of the thigh, and has often been considered to be caused by repetitive mild trauma to the site, we speculate that it is also attributed to the vulnerability of the site, as explained by the muscle structure.