Polyhydramnios and hypercalcemia associated with congenital mesoblastic nephroma: case report and a new appraisal.

Polyhydramnios and hypercalcemia are known complications of congenital mesoblastic nephroma. Hypercalcemia has been shown to cause polyuria. Polyuria is believed to be the probable cause for the polyhydramnios, but the exact mechanism remains unknown. To our knowledge, this is the first reported case of a relationship between hypercalcemia and polyhydramnios. A 26-year-old primigravida was diagnosed with congenital mesoblastic nephroma and polyhydramnios at 36 weeks' gestation. Neonatal hypercalcemia was detected immediately after delivery at 40 weeks' gestation. After removal of the nephroma, the calcium level normalized. Hypercalcemia may be the mechanism underlying polyhydramnios in cases of congenital mesoblastic nephroma. Calcium levels should be monitored after delivery, and prompt surgical removal of the tumor should be performed.