Evaluation of microscopic methods in the diagnosis of idiopathic steatorrhoea.

Of 14 cases of clinically and biochemically confirmed idiopathic steatorrhoea, 11 showed mucosal abnormalities when biopsy specimens from the upper small intestine were examined under the dissecting, the light, and the electron microscope. In the three remaining cases mucosal changes could be detected only under the electron microscope. The simple and inexpensive dissecting microscope can therefore be accepted as an efficient instrument for routine use in the diagnosis of idiopathic steatorrhoea and for the screening of cases which might merit further examination under the electron microscope. The light microscope allows the heights of the villi and the depth of the glandular layer to be measured and the limits of normality to be defined on a quantitative basis.The electron microscope reveals abnormalities in the microvilli of mucosal epithelial cells. The mildest changes consist of shortening and fusion of the microvilli and a lessened electron-density of the apical cytoplasm. Since these changes occur in mucosae which appear to be normal under the dissecting and the light microscope they are assumed to be related to the earlier stages of the disease and their significance is discussed in the light of this view.