Metanephric adenoma

Abstract

In a recent survey of more than one hundred childhood renal tumors in our Laboratory files, we identified a unique case characterized by an unusual degree of differentiation and cell maturity. Histologically this case was notable for an orderly array of small and uniformly-packed tubules with a rosette-like configuration. The nuclei were oval, smooth and of a bland appearance. Mitoses were absent. Many glomerular figures were intermingled. This renal tumor picture is somewhat different from that known as tubular Wilms' tumor because of the welldifferentiated adenomatous pattern and the absence of any blastema. The term metanephric adenoma is suggested for this tumor, which may represent the benign counterpart of Wilms' tumor.