Introduction : Peripheral nervous system (PNS) is a common involved site in cancer patients, .[1] but rare in leukemia. In leukemia patients, extramedullary myeloid tumors are considered to be of rare occurrence.[2]Because of these non-specific symptoms of neuroleukemiosis, special diagnostic tools should be considered (MRI, EMG, PET, etc). However, these seem to be expensive compared to their non-specific symptoms. In this case, authors used convenient and cost-effective ultrasound to search for origin of peripheral neuropathy. In this case report, we would like to present a clinical usefulness of ultrasound for early the diagnosis of neuroleukemiosis which lead to non-specific neurologic symptoms in peripheral nerve.
Case report: A 70-year-old man in remission for 6 years from acute myeloid leukemia (AML) was requested on consultation from the department of neurology for gradually increasing shooting pain and radiating pain of his left posterior tibia and sole. He had recent history of falling over backwards while walking down. The pain and weakness had been unresponsive to oral non-steroidal anti-inflammatory drug, etc. Results of lumbar spine MRI were insufficient to explain the symptoms. Assuming the pathology to be peripheral neuropathy, our next step was three times of pyriformis test block . But, the effect only lasted for a few hours. We examined both sciatic nerves with ultrasound. We founded hypoechoic and edematous left tibia nerve in mid-thigh & upper knee level on ultrasonography. Fig.1Enhanced Lt. thigh MRI revealed diffuse swelling and internal enhancement of left sciatic nerve combined with perilesional fluid collection at mid to distal thigh level implying sciatic nerve neuritis and differential diagnosis of involvement of lymphoma. Fig.2 Under the cooperation of orthopedics we carried out a open biopsy. It showed finally brought us the diagnosis of myeloid sarcoma.
Discussion : Neuroleukemiosis is a rare .Therefore, the diagnosis may be delayed due to confusion with the lumbar spine problem (spinal stenosis, lumbar HNP etc.)In addition, the length of time until detection be extended due to cost issue of MRI, PET etc. and risk that need to be confirmed by biopsy.In this case, we was able to diagnose quickly through the method of comparing both sciatic nerve using a cheap ultrasound.