Bilateral tibialis anterior muscle herniation simulating a soft tissue tumour in a young amateur football player.

Muscle herniation is a focal protrusion of muscle tissue through a defect in the deep fascial layer. Anterior tibial muscle is the most commonly affected muscle of the lower extremities because its fascia is the most vulnerable to trauma. Clinically it is characterized by asymptomatic or painful, skin-coloured, soft, subcutaneous nodules of various size depending on the position. The diagnosis is usually made clinically based on its typical manifestations, but ultrasonographic examination is useful for detecting the fascial defect and excluding other conditions caused by soft tissue tumours such as lipomas, angiolipomas, fibromas, schwannomas or varicosities. Although this entity is not rare, it has been less well documented in the dermatological literature. We report a case of bilateral tibialis anterior muscle herniation mimicking a soft tissue tumour in a young amateur football player.