Endometriosis in the Lumbar Plexus Mimicking a Nerve Sheath Tumor

Endometriosis consists of ectopic endometrial tissue outside of the uterine cavity. It is typically benign. It may cause neurological symptoms if involving the central or peripheral nervous system. We present in this report a 46-year-old Caucasian female with progressively worsening lumbar pain with radiation to her left anterior thigh. MR imaging showed an enhancing mass in the L4 neural foramen, intrepreted as a nerve sheath tumor. At operation the nerve showed extrinsic and intrinsic abnormality, proven to be endometriosis. Postoperatively, the patient reported relief from her radiculopathy. We review the previous cases, discuss the pathogenesis and additional characteristics that highlight intraspinal endometriosis, although rare, should be considered as a potential cause of neurologic symptoms in women. Surgical resection is recommended in cases having severe or worsening neurologic symptoms or signs of cauda equina syndrome. Adjunctive treatment may be used in cases of residual or recurrent lesions.