[Conservative surgery in metanephric renal adenoma].

OBJECTIVE

To confirm that metanephric adenoma is a benign tumor with no potential to malignancy, observing its course 6 years after conservative surgical management.

METHODS

A light microscopic, immunohistochemical and electron microscopic study of the surgical specimen were performed and the DNA euploidy and proliferation index were determined.

RESULTS

Metanephric adenoma is comprised of tubular epithelial structures of small diameter or with virtual lumen, with or without calcifications, psammoma bodies and bony trabeculae. No cell atypia or mitosis was observed. The immunohistochemical study is useful to discard the unlikely metastatic nature of the tumor. It has a euploid DNA distribution and there is practically no proliferation. Electron microscopy showed a scanty amount of microvilli and abundant material between the tubules that appeared to be similar to that of the basement membrane.

CONCLUSIONS

Knowledge about this benign disease entity is emphasized in order to avoid unnecessary radical nephrectomies.