A spherical mass of the right psoas muscle was found incidentally by magnetic resonance health examination in a 43-year-old woman. The patient had complained of numbness in her right leg over the previous six months and neuralgia at the time of computed tomography-guided core biopsy, which was done to establish the diagnosis. To our knowledge, femoral nerve neuropathy caused by an intramuscular schwannoma arising from the psoas muscle has not been previously published.