Fetal retroperitoneal neuroblastoma

Case contributed by Mohamed Saber
Diagnosis almost certain


Routine ultrasound check-up at the 36th week of pregnancy.

Patient Data

Age: 35 years
Gender: Female

Fetal ultrasound


Ultrasound shows fetal pelviabdominal well-defined ovoid soft tissue mass lesion presents internal echogenic calcific foci and prominent vascularity on the color duplex study.

MRI study shows a large well defined ovoid lower abdominal and pelvic solid mass lesion measures 4x4.5x6 cm. The mass is seen at the midline and posteriorly located, mostly retroperitoneal and related to the distal aorta. The mass is seen displacing the surrounding structures with a prominent mass effect on the urinary bladder. It presents homogenous intermediate signal intensity in T1w and T2w.  

Postpartum ultrasound


Postpartum ultrasound shows pelviabdominal well-defined ovoid soft tissue mass lesion and confirms internal calcifications and hypervascularity.

CT study shows a large well defined ovoid pelviabdominal solid mass lesion measures 3.8x5x7cm. The mass is midline, posteriorly located,  retroperitoneal, extends from the level of distal aorta downwards to the deep pelvis, abutting the anterior aspect of the lower lumbar and sacral spine, laterally displacing the iliac vessels, and anteriorly displacing the urinary bladder. It shows multiple internal calcific foci, moderate heterogeneous enhancement with hypodense areas of cystic breakdown.

Case Discussion

Although rare, several tumors may be diagnosed antenatally. These fetal tumors are a diverse and unique group of conditions. Among all fetal tumors, neuroblastoma is the most common tumor overall.

Adrenal glands are the most common site of origin of neuroblastoma (35%) while the retroperitoneum is the second most common (30-35%).

Considering that neuroblastoma is the most common fetal tumor, retroperitoneal location, and the presence of internal calcifications seen in 80-90% of neuroblastoma cases all are highly suggestive of this diagnosis.

The patient was transferred to a tertiary hospital of pediatric oncology.

Ultrasound contribution by Dr.Shaimaa Hussien and Dr. Somia Elbadawy

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