The Natural History of Uterine Leiomyomas: Light and Electron Microscopic Studies of Fibroid Phases, Interstitial Ischemia, Inanosis, and Reclamation
Figure 6
Ultrastructural features of phenotypic transformation. This side-by-side comparison of myometrial smooth muscle cells in (a) with the transformed fibroid myocytes in (b) illustrates some of the electron microscopic features of the phenotypic transformation. The myometrial myocytes in (a) display abundant, relatively homogeneous cytoplasm that is filled with fine actin filaments (asterisk), oriented in parallel array in the long axis of the cells. Also evident are interspersed dense bodies (short arrow), focal clusters of mitochondria (long arrow), and a nucleus with a crenulated nuclear border (arrowhead) that is suggestive of the contractile state. In contrast, the fibroid in (b) exhibits more intercellular stroma and slender, streamlined cells with less cytoplasm, marked reduction in the fine actin filaments, increased swollen endoplasmic reticulum (arrow), and elongated, pointed nuclei. In (c), the myometrial myocyte displays a cytoplasm filled with actin fine filaments (asterisk), interspersed dense bodies (short arrow), clusters of mitochondria (long arrow), and a nucleus with a rounded end. In contrast, the fibroid myocyte in (d) exhibits extensive, dilated endoplasmic reticulum (short arrow), swollen mitochondria (long arrow), greatly reduced myofilaments limited to the periphery of the cell (asterisk), and a nucleus with a pointed end. Original magnification of both (a) and (b): 2550x, (c) and (d): 11,500x.
