Tibialis anterior muscle hernia: a rare differential of a soft tissue tumour.

To cite: Govindarajan A, Inigo A. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2015212462 DESCRIPTION A 57-year-old man with a history of fall injury presented with swelling in the anterior aspect of his left leg, with occasional pain while walking. On examination, the swelling had a rubbery consistency and was partly reducible. The swelling increased in size on standing and activity. Differentials including superficial varicosity, vascular malformation, muscle hernia and soft tissue tumour were considered and MRI was carried out. MRI showed protrusion of the tibialis anterior through a focal defect in fascia overlying the muscle (figure 1). The defect measured 1.5×1.4 cm. There was a subtle T2 and short τ inversion recovery hyperintense signal within the herniated muscle, possibly due to oedema (figures 2 and 3). A diagnosis of tibialis anterior muscle hernia was confirmed and the patient was managed with compression stockings and activity restriction. Ihde classified the aetiology of muscle hernias into traumatic and constitutional (generalised weakness of fascia). In the lower limb, the most commonly involved muscle is the tibialis anterior due to its weak and vulnerable fascia. A dynamic ultrasonogram or MRI can confirm the diagnosis. The treatment of muscle hernias depends on the severity of symptoms. While they can be managed conservatively with compression stockings and activity restriction, persistently symptomatic muscle hernias need longitudinal fasciotomy.