Peculiar Ultrastructural Features in the Cytoplasm of Cells from Human Effusions Associated with Malignant Disease

Abstract

A peculiar structure revealed by the electron microscope in a few cells from two human pleural fluids, showing the morphologic features of metastasizing cancer cells in effusions, is described. It has the appearance of a rod-shaped pentalaminary structure approximately 25–35 nm thick formed by an outer double membrane, surrounding a central, more dense axis showing transverse striations at about 10-nm intervals. The double membrane often exhibits a terminal expansion connected with the endoplasmic reticulum and it is sometimes associated with microfilaments. These structures could be a variant of or represent a step in the formation of confronting cisternae, but the periodic striations they show in the more dense lamella give them some resemblance to a Langerhan's cell granule. To date, such striations have not been seen in confronting cisternae.

Key Words:

• human effusion
• cancer cells
• confronting cisternae