Abstract:

Objective To investigate the clinicopathological characteristics, immune phenotype and differential diagnosis of congenital mesoblastic nephroma. Methods The clinicopathological characteristics of 4 cases of congenital mesoblastic nephroma were analysed, and related literatures were reviewed. Results The tumors occurred in children younger than 2 years old, generally presenting a capsular complete lump. All the 4 cases were classical congenital mesoblastic nephroma. The tumors consisted of spindle cells with elongated nucleus. Tumors grew with a bunch or woven pattern. The cells arranged net-like in sparse area, with elongated nucleus, obvious nucleoli and nuclear fission of 3-5/10 HPF. A small amount of irregular distribution of the remaining kidney tissues was found between the tumor cells. Immunohistochemistry indicated that there were positive expression of vimentin and partially positive expression of smooth muscle actin in the tumor cells. No tumor recurrence or metastasis was observed during follow-up. Conclusion Congenital mesoblastic nephroma is a low-grade malignant tumor in infants and young children, which exhibits spindle cells in histomorphology. The prognosis may be favorable after complete resection.

Key words: congenital mesoblastic nephroma, kidney, pediatric neoplasm