Myeloid sarcoma is a solid, extramedullary
tumor comprising of immature myeloid cells. It may occur in any organ; however, the invasion of peripheral nervous system is rare. Herein, we report the case of
myeloid sarcoma on the brachial plexus. A 37-year-old woman with
acute myelogenous leukemia achieved complete remission after
chemotherapy. One year later, she presented right
shoulder pain, progressive weakness in the right upper extremity and
hypesthesia. Based on magnetic resonance images (MRI) and electrophysiologic study, a provisional diagnosis of
brachial plexus neuritis was done and hence
steroid pulse
therapy was carried out. Three months later the patient presented epigastric
pain. After upper gastrointestinal endoscopy,
myeloid sarcoma of gastrointestinal tract was confirmed pathologically. Moreover, 18-fluoride fluorodeoxyglucose positron emission tomography showed a fusiform shaped mass lesion at the brachial plexus overlapping with previous high signal lesion on the MRI. Therefore, we concluded the final diagnosis as
brachial plexopathy due to
myeloid sarcoma.