Rapidly expanding mass in a neonate

Abstract

Congenital mesoblastic nephroma is the most common solid renal tumor in the neonate.' This neoplasm was discovered by ultrasound examination performed to reevaluate known bilateral adrenal hemorrhages in a neonate. The renal mass was not present on a n ultrasound examination performed 22 days earlier. CASE REPORTA male infant was born as the result of a nontraumatic spontaneous vaginal delivery at 41 weeks of gestation. There had been no polyhydramnios noted. The child had a nuchal cord and required vigorous suctioning. Apgar was 5 and 8 at 1 and 5 min, respectively. Birth weight was 3,953 g.Routine physical examination revealed a flank mass on the left. The baby was doing well clinically. However, jaundice was evident at age 40 h, and bilirubin was noted to be 10.3 mg/dl. Repeat bilirubin at age 66 h was 13.5 mg/dl. Direct Coombs' test on the cord blood was negative.An intravenous urogram performed prior to transfer of the child to our institution, the Children's Hospital of Philadelphia, was reviewed (Fig. 1). Both pelvocalyceal systems were well visualized. There was no evidence of an intrarenal mass. The upper poles of both kidneys were displaced laterally, more so on the left side. There was no evidence of intraabdominal calcification. The urinary bladder was well distended. The entire left kidney was minimally displaced inferiorly.The patient was first seen at our institution at age 3 days. Static and real-time ultrasound scans were obtained. Well-defined bilateral suprarenal areas of echolucency were visualized, measuring 2.7 cm x 1.7 cm x 2.4 cm on the right and 2.7 cm x 1.2 cm x 3 cm on the left (Fig. 2). These appeared to be located in the adrenal glands and were consistent with previous hemorrhage. Some normal adrenal tissue was visualized as well. No evidence of an intrarenal mass was seen. The left upper pole was displaced posterolaterally, and the entire left kidney was more inferiorly placed than usual. The remainder of the abdomen and pelvis were scanned, and no abnormality could be detec ted .