Congenital mesoblastic nephroma: clinicopathological features and molecular genetic analyses / 临床与实验病理学杂志

ABSTRACT

To discuss clinicopathological features and molecular genetic change of congenital mesoblastic nephroma (CMN).Methods Nine cases diagnosed as CMN were analyzed retrospectively in this study.Histological features,immunohistochemical profiles and ETV6 gene rearrangement status were assessed.Results All patients were within two years of age and eight of them were within one year.The average diameter of tumors was 9.5 cm (3.2-15.0 cm).These series cases included 3 classic CMN,5 cellular CMN and 1 mixed CMN.Cystic degeneration was found in 5 cases,and cartilage islands were observed in 2 cases.Compared with classic CMN,tumor size was bigger,and hemorrhage,necrosis and mitotic figures were easily to see in cellular CMN.All the tumor cells were positive for vimentin and negative for WT-1 by immunohistochemistry.ETV6 gene rearrangement was detected in 5 cases (including 4 cellular CMN and 1 classic CMN).Three cellular CMN harbored ETV6 gene translocation,1 mixed CMN and 1 cellular CMN were negative for ETV6 gene translocation by FISH analysis.The follow up data were obtained in 7 cases and 2 cases were lost.All the 7 patients were alive without evidence of recurrence and metastasis from 5 to 46 months.Conclusion CMN is a rare infant renal tumor with unique clinicopathological characteristics.Most of cellular CMNs harbor ETV6 gene translocation.The prognosis of CMN is relative good and needs to be differentiated from other malignant renal tumors.