Metaphase analysis of metanephric adenoma reveals chromosome Y loss with chromosome 7 and 17 gain.

A 61-year-old man underwent wedge excision of a 3-cm right renal metanephric adenoma. This recently recognized tumor has been considered benign, although no genetic studies have been reported. Metaphase analysis demonstrated a 47,X,-Y,+7,+17 karyotype. These results are consistent with a clonal neoplastic disorder.