Ultrastructural study of primary lacrimal adenocarcinoma.

PURPOSE Primary adenocarcinoma of the lacrimal gland is a rare malignant tumor of the orbit. Up to now, there has been no presentation of its ultrastructural features. The histopathological findings and fine structures of one case of adenocarcinoma of the lacrimal gland are described in the present work. METHODS The patient was a 59-year-old Japanese man with proptosis that had persisted for one month. A tumor was extirpated, and the tissues were prepared for light and electron microscopic examination. RESULTS Electron microscopic examination demonstrated that the tumor cells had well-developed microvilli and lumens. These ultrastructure features are similar to those seen in adenocarcinomas at other sites. CONCLUSIONS These observations suggest that the accurate diagnosis of rare malignant adenocarcinoma depends not only on routine techniques such as light microscopy of hematoxylin-eosin and PAS-diastase stained slides, but also on electron microscopic findings.