Presacral fibrosarcoma is a rare malignant tumor in childhood. Because of its rarity in the presacral
region, it is often missed from the differential diagnosis of presacral mass in childhood. The authors present a
case of large presacral fibrosarcoma involving spinal canal, with an initial presentation of back pain and
abnormal gaiting.

Keywords: Childhood fibrosarcoma, Presacral mass, Sacrum