MRI pelvis confirms the presence of a well defined soft tissue mass (low T1 signal and iso-high intensity T2 signal) anterior to the sacrum with extension through the right sacral neural foramina into the spinal canal and extension laterally into the right greater sciatic notch. Despite encasing the sacrum, there is no intrinsic marrow signal change to suggest involvement. There is a clear fat plane between the mass and anteriorly sited uterus/vagina and urinary bladder. The mass demonstrates diffusion restriction. There was minimal heterogeneous enhancement following contrast administration.
Imaging of the remainder of the abdomen confirmed mild bilateral hydronephrosis. Normal appearances of the adrenal glands. No lymphadenopathy.
Parasacral mass with intraspinal extension and invagination along neural pathways is consistent with a pelvis neuroblastoma.
There are no imaging features of sacrococcygeal teratoma.