XXXX (leiomyomatosis peritonealis disseminata): a clinicopathologic study of 20 cases with ultrastructural observations.

@entity1 @entity230 @entity298
@entity298 ( @entity298 ) occurs in @entity1 of reproductive age. Of 20 @entity1 with @entity298 in this study, 10 were pregnant or immediately postpartum, and 7 were taking oral contraceptive @entity230 . Only three of the 20 @entity1 were not pregnant or taking exogenous hormones. All @entity298 nodules were composed mainly of spindle cells, but decidual cells were admixed with the spindle cells in some of the nodules in six of the 10 pregnant and postpartum @entity1 . Electron microscopy was applied to the nodules from six @entity1 representing the three different hormonal backgrounds. All contained smooth muscle cells. One was composed exclusively of smooth muscle cells, while four of the six contained smooth muscle cells predominantly but were admixed with myofibroblasts or altered smooth muscle cells and fibroblasts. Decidual cells were conspicuous in the nodules examined ultrastructurally from a pregnant @entity1 . Despite incomplete excisions, none of the 14 @entity1 with follow-up had progressive disease. Complete or partial regression of @entity298 was verified by "second-look" laparotomy in four @entity1 , but a repeat cesarian section in a fifth @entity1 revealed persistence (or recurrence) of @entity298 1.5 years after the initial diagnosis. @entity298 probably results from an unusual predisposition, or selective sensitivity, of subperitoneal mesenchymal stem cells in some @entity1 to undergo metaplasia and differentiation to smooth muscle, fibroblasts, myofibroblasts, and decidual cells. In the majority of @entity1 , hormonal stimulation is an initiator or promoter of the process.
