A 14-year-old girl demonstrated increased iron concentration and transferrin saturation, suggesting iron overload of unknown origin. Liver biopsy showed no fibrosis or hepatocytic atrophia. Nevertheless, Prussian blue reaction for histochemical detection of iron demonstrated very weak positive granules in a few hepatocytes on the periphery of hepatic lobules in close connection to bile capillaries. This very early stage of hemochromatosis was confirmed by TEM and EELS for iron accumulation inside hepatocytic lysosomes and residual bodies. Such siderosomes were scarce in number and iron content, compared to a case of manifested hemochromatosis and liver cirrhosis (Jonas L, Fulda G, Salemeh T, et al. Ultrastruct Pathol. 2001; 25: 111-118.). Liver iron concentration as measured by inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) yielded 2.005 mg/g tissue dry weight, which was considered not significantly increased. In the absence of known causes for secondary iron overload, the early diagnosis was evidenced by genotyping, revealed homozygosity for the HFE gene C282Y mutation, demonstrating the presence of hereditary hemochromatosis.