Ultrastructural studies of the female breast: I. 9 + 0 cilia in myoepithelial cells.

9 + 0 cilia associated with diplosomes were observed in myoepithelial cells of the ductal system in the undiseased, resting, adult female breast. Ciliary diameter was 250 nm, and the longest found was 830 nm. The centrioles comprising the diplosome were 500 nm in length and 160 to 200 nm in diameter. Satellite bodies were associated with the diplosome but there was no rootlet system. Evidence suggested that all myoepithelial cells bear a cilium. The possible functions of the cilia in a sensory role as chemo- or mechanoreceptors related to myoepithelial and epithelial activities are discussed.