Abstract
Congenital mesoblastic nephroma (CMN) is a rare renal tumor, but the commonest tumor
of early infancy. It can be detected prenatally as a renal mass and is associated
with prematurity, polyhydramnios, and neonatal hypertension. We report a case of congenital
mesoblastic nephroma which presented as a large unilateral solid renal mass detected
at 33 weeks of gestation associated with oligohydramnios and small for gestational
age (SGA) fetus. Ultrasound features were a large hypoechoic mass arising from the
upper pole of the Left kidney measuring 52 ⅹ 43 ⅹ 32 mm. Inside the mass there were
incomplete septae and a few cystic areas, likely hemorrhagic areas, with minimal peripheral
vascularity. The mass was surrounded by a hyperechoic capsule. The left adrenal gland
could be imaged separately. The baby was delivered by a lower segment cesarean section
(LSCS) at 38 weeks of gestation. After birth, the baby presented with a mass per abdomen
with no other symptoms and no hypertension. CT scan and ultrasound guided biopsy confirmed
the finding of the cellular variant of congenital mesoblastic nephroma. Left radical
nephrectomy with adrenal gland conservation was performed on day 8 of life. Postoperative
adjuvant chemotherapy was administered. On follow-up, the baby is asymptomatic with
no relapse or metastasis. Fetal CMN and Wilms tumor have overlapping ultrasound features
and are difficult to differentiate on prenatal ultrasound. Prenatal detection of fetal
renal tumors and timely neonatal management improve perinatal outcome.
Keywords
Congenital mesoblastic nephroma (CMN) - Wilms tumor - Ultrasonography - Prenatal detection
- Fetal tumors
