Unilateral Agenesis of Iliopsoas Muscle

Agenesis of the psoas minor muscle is very common as it can be absent in approximately 56% of the population. Moreover, previous three case reports described hypoplasia of the psoas muscle. However, our case had complete agenesis of the three iliopsoas muscle components on the right side. A 26-year-old woman presented with right-side weak hip flexion that had persisted for 2 years. Magnetic resonance imaging revealed complete agenesis of the right iliopsoas muscle, and no spine pathology was detected. Radiologists should put agenesis of the iliopsoas muscle into consideration in patients presented with weak hip flexion especially when no spine pathology is detected. Follow-up is advised to study the long-term effects of iliopsoas muscle agenesis. To the best of our knowledge, we believe that this is the first report in the general literature.