Age / Sex : 27 / M

Chief complaint : lateral malleolar mass

What is the diagnosis?
(Can you see the mass on MRI?)


What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer)

Courtesy : 채지원 (Jee Won Chai), 서울특별시 보라매병원 (SMG-SNU Boramae Medical Center)

Muscle hernia

Discussion

Muscle hernia is a challenging diagnosis. Ultrasound findings generally are negative because patients come to ultrasound study from home when they are at rest. When the operator of ultrasound suspects a muscle hernia, he has to scan the affected limb or the affected organ dynamically at rest and after stressing the limb.
Most common in Tibialis anterior muscle.

Findings
1. Muscle bulging out from the fascia with a defect in the fascia itself.
2. Prominent vascular structure identified in a minority of cases using color or power Doppler sonography.

References
1. Sonography of Muscle Hernias. AJR 2003 Feb;180(2):395-9.
2. The importance of dynamic ultrasound in the diagnosis of tibialis anterior muscle herniation. Crit Ultrasound J. 2014 Sep 4;6(1):14.