A case of adult mesoblastic nephroma: ultrastructure and discussion of histogenesis

A benign fibromyomatous kidney tumor with deep seated tubular structures in a 20-year-old woman is reported as a case of adult mesoblastic nephroma. Ultrastructural examination confirmed the fibromyomatous nature of the stroma and the tubules appeared to be an integral part of the tumor. The histogenetic relationship to congenital mesoblastic nephroma, Wilms tumor and other tumors is discussed. Radical nephrectomy was performed and the patient remained well 1 year later.