Leiomyomatosis peritonealis disseminata.

The ninth documented case of leiomyomatosis peritonealis disseminata (LPD) combined with pregnancy is presented. Light and electron microscopic studies revealed that the smaller tumors were composed partly of decidual cells and partly of fibroblasts, and the larger tumors contained cells resembling smooth muscle cells. Plasma steroid levels were determined during pregnancy. Estrogen levels were within normal range, but progesterone levels were lower than normal, resulting in relative hyperestrogenism. In the case presented, pregnancy, especially with relative hyperestrogenism, may have been a major cause of LPD.