Atypical Endometriosis - An Overview of the Issue and Personal Experiences

Endometriosis is a chronic, estrogen-dependent, inflammatory disease characterized by the growth of endometriotic tissue outside the uterus. Among the wide spectrum of clinical manifestations of endometriosis, chronic pelvic pain, dysmenorrhea, dyspareunia and subfertility are the main symptoms that significantly reduce the quality of life of affected women. Despite the fact that endometriosis is considered a benign disease, it shares some features typical of malignant tumors. One of them is abnormal morphology, which indicates atypia of the glandular epithelium without signs of hyperplasia, or it may be glandular hyperplasia, which may or may not be accompanied by cellular atypia. This situation is reflected in the term atypical endometriosis, the diagnosis of which is not easy. Cellular atypia of a severe degree can be of reactive origin, so the mutual differentiation of dysplastic and reactive changes in endometriotic tissue is limited and problematic. Our working group from the scientific center for the treatment of endometriosis at the Znojmo Hospital recently dealt with atypical endometriosis and pointed out the potential utility of immunohistochemistry in its diagnosing. Using a simple immunohistochemical panel with antibodies against estrogen receptors, progesterone receptors, and the tumor suppressor p53, we found significantly lower levels of hormone receptor expression and increased p53 expression in atypical endometriosis compared to normal (typical) endometriosis. Due to the low number of cases analyzed and the inconsistent results of studies dealing with hormone receptors (and other markers) in atypical endometriosis, the usefulness of the immunohistochemical panel described in our study must be verified on a larger number of cases. In routine histopathological practice, atypical endometriosis is not a well-known entity. However, it is important to become familiar with it because its presence is associated with a higher incidence of a certain group of tumors known as endometriosis-associated cancers, especially endometrioid carcinoma and clear cell carcinoma.