ABSTRACT
The most common causes of abdominal mass are neuroblastoma, germ cell tumors, hepatoblastoma and congenital mesoblastic nephroma. Congenital mesoblastic nephroma (CMN) accounts for more than 90% of all renal tumors seen in the first three months of life. Total nephrectomy is curative. Neuron-specific enolase is a glycolytic enzyme that is localized primarily to the neuronal cytoplasm. Its sensitivity is especially high for neuroblastoma and small cell lung cancer. In this paper, we report a newborn with abdominal mass that was firstly considered as neuroblastoma due to calcifications observed on ultrasonography and high levels of serum neuron-specific enolase. After histopathological evaluation of the lesion, the patient was diagnosed as having atypical (cellular) congenital mesoblastic nephroma.