THE ORIGIN AND DEVELOPMENT OF BENIGN STROMATOSIS OF THE OVARY

Summary

A lesion consisting of isolated foci of endometrial stroma in the ovarian cortex is discribed. These become common from about the age of 40 years, although they are sometimes present earlier, and effect more than a third of all ovaries. Evidence is offered that these foci develop from the implantation of endometrial stromal cells shed during menstraution and probably at other times. When deprived of their blood supply these cells some to resemble a cluster of histiocytes or serosal cells, and they migrate in this from through the uterine tube to the ovarian surface. Here they become revascularized to resume their familiar form of a loose but cellular network, forming islands in the ovarian cortex. The component cells may then evolve into histiocytes, decidual cells or smooth muscel, but most lesions become hyaline with loss of cellularity and the formation of elastic tissue. Such lesions are very common and are found in most ovaries from patients over the age of 45 years. The term “benign stromatosis” is proposed for this lesion which probably forms the basis of ectopic decidual reactions and some forms of ovarian pathology.