Histologic classification of specimens from women affected by superficial endometriosis, deeply infiltrating endometriosis, and ovarian endometriomas.

In this retrospective observational study involving 176 patients and 271 biopsies, the histologic differentiation in superficial endometriosis, deeply infiltrating endometriosis, and ovarian endometriomas was evaluated according to a previously proposed classification system. Results showed a predominance of the undifferentiated glandular pattern (33.5%) and mixed glandular pattern (46.9%) in deeply infiltrating endometriosis lesions, whereas the well-differentiated glandular pattern (41.8%) was most frequently seen in superficial endometriosis lesions, and in ovarian endometriomas a predominance of both the undifferentiated (40.5%) and mixed patterns (37.8%) was observed.