Congenital metastatic neuroblastoma with placental involvement as a rare cause of non-immune fetal hydrops.

Non-immune hydrops fetalis represents the end-stage status of a variety of diseases, including metastatic tumors. We report a case of non-immune hydrops fetalis associated with multiple disseminated echogenic nodular lesions detected by ultrasound and confirmed by magnetic resonance. Cordocentesis demonstrated anemia and thrombopenia. Differential diagnosis included histiocytosis X, acute leukemia or metastatic disease. A stillbirth was diagnosed at week 25 + 6. The autopsy revealed hydrops fetalis, a right adrenal gland mass, multiple disseminated nodules histologically composed of small round blue cells positive for synaptophysin, and placental involvement, concordant findings with congenital undifferentiated neuroblastoma Stage M. No chromosomal abnormalities were associated, nor amplification abnormalities in MYCN and ALK genes. Metastatic neuroblastoma should be considered in the differential diagnosis of non-immune hydrops fetalis associated with multiple nodular lesions.