A 10-year old girl with neck pain.

Neuromyelitis optica (NMO), (Devic's disease), is a relatively uncommon autoimmune disease predominantly involving the spinal cord and optic nerves. We present a 10 year-old female with intermittent neck pain, progressive right upper and bilateral lower extremity weakness. MR imaging and intraoperative findings were strongly suggestive of a neoplastic process. However, pathologic examination showed an inflammatory demyelinating lesion and serological studies were positive for NMO-IgG. The patient improved dramatically following resection of the compressive "pseudotumor", with resolution of her preoperative deficits. This case underscores the diverse clinical presentation of neuromyelitis optica and the importance of maintaining a broad differential diagnosis in pediatric lesions resembling neoplasms.