Germanium-induced nephropathy: report of two cases and review of the literature.

We report two cases of renal failure following long-term ingestion of germanium dioxide (GeO2) and comment on eight other cases reported in Japan. Ge-induced nephropathy is characterized by insidious onset of renal failure without proteinuria or hematuria after oral intake of Ge-containing compounds for more than several months, and by degeneration of renal tubular cells with minor glomerular abnormality in histology. When patients ceased to ingest Ge compounds, renal function gradually recovered but never returned to the normal range. Serious extrarenal complication can contribute to an unfavorable prognosis.