Rare Intramedullary Myeloid Sarcoma Mistaken as Acute Transverse Myelitis

Corresponding author: Jung-Woo Hur Department of Neurosurgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea Tel: +82-2-2258-6353 Fax: +82-2-594-4248 E-mail: neurotique79@gmail.com Myeloid sarcoma is a rare extramedullary tumor of immature myeloid cells. It more often develops with the underlying acute myeloid leukemia, but it can also occur with chronic myeloid leukemia (CML), myelodysplastic syndrome and rarely even with the absence of marrow involvement. Spinal epidural myeloid sarcoma is uncommon, and intramedullary presentation is exceptionally rare. In this report the authors report an unusual case of spinal intramedullary myeloid sarcoma after completer remission from CML several years ago. He was mistakenly diagnosed as acute transverse myelitis and treated with high-dose steroid and plasmaparesis without improvement. Magnetic resonance imaging revealed intramedullary mass-like lesion with hyper-intensity in T2-weighted image and mild homogeneous enhancement. Myeloid sarcoma should be considered as a possible differential diagnosis when patient with history of myeloid leukemia present intramedullary tumor and pathologic confirmation with open biopsy is mandatory for the exact diagnosis.