title: Neuromuscular choristoma presenting with unilateral limb hypoplasia in a 3-year-old boy.
abstract: Neuromuscular choristomas (NMCs) are rare benign peripheral nerve lesions in which skeletal muscle tissue is admixed with nerve fascicles.
  
  
  
  We describe a case of sciatic nerve NMC presenting with unilateral limb hypoplasia, monoparesis, and equinovarus contracture in a pediatric patient. We outline the unique clinical presentation and diagnostic work-up for our patient, including electromyographic and imaging studies.
  
  
  
  MRI revealed fusiform enlargement of the sciatic nerve, <50% intralesional fat, and signal characteristics similar to those of muscle tissue. Ultrasound was utilized to characterize atrophy and fatty infiltration of affected muscles. The patient was treated conservatively with a customized physical therapy program and lower limb orthosis.
  
  
  
  Emerging diagnostic criteria are highlighted with the goal of distinguishing NMCs from more common peripheral nerve lesions. This can have important clinical consequences, as unnecessary biopsies are associated with aggressive fibromatosis, a potentially devastating complication. Muscle Nerve 54: 797-801, 2016.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Mayo Clinic, 200 First Street, Rochester, Minnesota, 55905, USA. obrien.travis1@mayo.edu.
authors.forename: Travis G
authors.initials: TG
authors.lastname: O'Brien
authors.affiliation: Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
authors.affiliation: Department of Physical Medicine and Rehabilitation, Mayo Clinic, 200 First Street, Rochester, Minnesota, 55905, USA.|Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Boon
mesh_terms: D002675:Child, Preschool; D002828:Choristoma / Q000150:complications / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D007866:Leg / Q000000981:diagnostic imaging*; D008297:Male; D020426:Sciatic Neuropathy / Q000150:complications / Q000000981:diagnostic imaging*
keywords: neuromuscular choristoma; neuromuscular ultrasound; pediatric neuromuscular disease; peripheral nerve lesion; post-biopsy fibromatosis