The Natural History of Uterine Leiomyomas: Light and Electron Microscopic Studies of Fibroid Phases, Interstitial Ischemia, Inanosis, and Reclamation
Figure 5
Phenotypic transformation: loss of lateral bars. Lateral bars (arrows) connecting myometrial smooth muscle cells in (a) are believed to represent sites of gap junction attachments between adjacent cells for purposes of coordinated contraction. These lateral bars, or intercellular attachments, are not seen between the fibroid tumor cells in (b). We believe that this is another indication of the phenotypic transformation to non-contractile cells. In (c), many of the fibroid myocytes exhibit lateral buds (long arrows), imparting a knobby appearance to the free borders of the cells. It is thought that these buds may represent remnants of the lateral bars. Note that the cytoplasmic borders of contiguous myocytes within the fascicle, however, do not show these lateral buds, but rather show retention of lateral bars, or attachments (short arrow), as noted in the myometrium. In (d), there are a few myocytes displaying lateral buds, which have a more frayed or feathered appearance (short arrows). Note that in the fully transformed cells on the left (long arrow), there are neither lateral bars or lateral buds. Original magnification of (a) and (b): 330x, (c) and (d): 132x.
