Fetal adrenal hemorrhage
Fetal adrenal hemorrhage is an uncommon occurrence and must be differentiated from other lesions especially neuroblastoma.
Pathology
The exact cause of adrenal bleeding in utero is not well known at the time of writing. It has been associated with birth trauma (breech birth), perinatal asphyxia, sepsis, and congenital infections (classically syphilis) .
Location
It can occur unilaterally or bilaterally. There is a greater incidence on the right side (75%) .
Radiographic features
Ultrasound
An adrenal hemorrhage may be seen as a mass above the fetal kidneys and will demonstrate changing characteristics in terms of echotexture on sequential images as it evolves from hyperechoic to isoechoic to hypoechoic and finally anechoic cystic are with or without septations. Color Doppler interrogation will not show any associated intrinsic vascularity. The hematoma may also change in size through time. Calcification of the adrenal may be the consequence of prior hemorrhage (although calcification is also seen in neuroblastoma) .
Differential diagnosis
For a fetal adrenal mass consider:
- fetal neuroblastoma: often has associated vascularity
- subdiaphragmatic pulmonary sequestration (extralobar)
- has a predilection towards the left side
- vascular supply from aorta may be seen
- fetal adrenal cyst: consideration for hypoechoic lesions