Distinction between atypical mesothelial cells and malignant cells by scanning electron microscopy.

An examination of body cavity fluid specimens with correlated light, transmission and scanning electron microscopy revealed several surface features that distinguished between malignant cells and atypical mesothelial cells. The microvilli of malignant cells generally were widely distributed and showed a variation in appearance, irregular overlapping and the presence of fused and branched forms. Microvilli on the surface of atypical mesothelial cells were patchy in distribution, relatively uniform in length and diameter and generally lacking in irregular forms. These findings suggest that scanning electron microscopy may be of diagnostic value in the examination of effusions in certain cases.