Ultrastructure of fallopian tube carcinoma.

Fallopian tube carcinoma is one of the rarest of primary gynecologic malignancies. Normal tubal epithelium is composed of secretory, ciliated, and intercalary cells. To determine the cellular composition and ultrastructural details of this rare neoplasm, a moderately well-differentiated tubal carcinoma was studied with the electron microscope. A prominent feature was the formation of numerous ultramicro alveolar spaces lined by cell surface microvilli. The nuclei of the neoplastic cells demonstrated a variety of fine structural abnormalities. Based on cell size and shape criteria, a possible dual tumor cell population was suggested. However, no cilia were seen in any of the tumor cells and almost all were devoid of secretory granules. These latter observations suggest that this tumor was primarily a proliferation of intercalary cells.