Scanning electron microscopy of adenomatoid tumours.

Four adenomatoid tumours of the epididymis were embedded in paraffin wax, sectioned and the sectioned surfaces examined by scanning electron microscopy using the secondary electron mode. The solid faces of the sectioned neoplasms were damaged by the preparative technique but the depressed luminal surfaces of the tubules were well preserved and yielded useful information. Large areas of luminal surface were examined and the presence and distribution of microvilli were noted. In addition, there was a more complex cell surface pattern of intersecting cord-like elevations. Desquamating cells were seen within the tubules and the cytoplasmic bridges noted by light microscopy were shown to be thin cytoplasmic partitions. These findings are consistent with the mesothelial theory of histogenesis. Scanning electron microscopy can provide useful information about the internal structure of neoplasms even with simple preparative techniques.