Predominately solid large sacrococcygeal teratoma at 23 weeks gestation

(A) Sagittal view of the distal spine shows a large solid tumor (arrow) off the caudal end of the fetus.
(B) Due to mass effect on the bladder, there is bilateral hydronephrosis. Given the large size and solid nature of this tumor (arrow), the fetus needs to be carefully monitored for development of hydrops.