Encyclopedia of Pathology

Living Edition
| Editors: J.H.J.M. van Krieken

Congenital Mesoblastic Nephroma

  • Anna Caliò
  • Diego Segala
  • Guido MartignoniEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-28845-1_4795-1


Congenital mesoblastic nephroma is a low-grade fibroblastic neoplasm arising in the renal sinus of children.

Clinical Features

  • Incidence

    It comprises 5% of pediatric renal neoplasms.

  • Age

    It is the most common kidney tumor in the first 3 months of life and is uncommon after 6 months.

  • Sex

    There is no gender predominance.

  • Site

    They are located in the renal sinus.

  • Treatment

    The treatment of choice is surgical excision.

  • Outcome

    Mesoblastic nephroma is a low-grade neoplasm; it has infiltrative borders which must be studied carefully because the risk of recurrence appears to be dependent upon the completeness of the resection (Furtwaengler et al. 2006). Only rare cases with hematogeneous metastases have been reported, which are treated with chemotherapy (Loeb et al. 2002).


Grossly this neoplasm is usually large, and its cut surface resembles that of a leiomyoma (firm, whorled or trabeculated, and light colored). The tumor is not encapsulated and typically interdigitated with the surrounding renal parenchyma.


Congenital mesoblastic nephroma is a moderately cellular proliferation of thick interlacing bundles of spindle cells with elongate nuclei which usually infiltrate renal and perirenal tissues resembling a fibromatosis (Fig. 1).
Fig. 1

Bundles of spindle neoplastic cells with elongate nuclei infiltrating renal parenchyma

Glomeruli and renal tubules are commonly entrapped. Mitotic figures are usually rare. Another pattern consists of a densely cellular proliferation of polygonal cells with more frequent mitotic figures (8–30 per 10 high-power fields).


These tumors are frequently immunoreactive for actin with infrequent desmin labeling; CD34 is negative.

Molecular Features

Cellular congenital mesoblastic nephroma harbors a specific chromosome translocation, t(12,15), which results in the fusion of the ETV6 and NTRK3 genes (El Demellawy et al. 2016). The gene fusion has not been found in the classic variant.

References and Further Reading

  1. El Demellawy, D., Cundiff, C. A., Nasr, A., et al. (2016). Congenital mesoblastic nephroma: A study of 19 cases using immunohistochemistry and ETV6-NTRK3 fusion gene rearrangement. Pathology, 48, 47–50.CrossRefGoogle Scholar
  2. Furtwaengler, R., Reinhard, H., Leuschner, I., et al. (2006). Mesoblastic nephroma – A report from the GPOH. Cancer, 106, 2275–2283.CrossRefGoogle Scholar
  3. Loeb, D. M., Hill, D. A., & Dome, J. S. (2002). Complete response to recurrent cellular congenital mesoblastic nephroma to chemotherapy. Journal of Pediatric Hematology/Oncology, 24, 478–481.CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Diagnostic and Public Health, Section of PathologyUniversity of VeronaVeronaItaly
  2. 2.Department of PathologyPederzoli Hospital, Peschiera del GardaPeschiera del GardaItaly