Immunohistochemical Study of Estrogen and Progesterone Receptors and the Proliferation Marker Ki-67 in Abdominal Wall Endometriosis

Introduction: The scar from pelvic surgery in the abdominal wall can be a site of endometriotic implants in 0.03 to 1% of patients. This study aims to evaluate the immunohistochemical expression of the estrogen receptor (ER), progesterone receptor (PR), and cell proliferation marker Ki-67 in patients with abdominal wall endometriosis.

Materials and Methods: We investigated seven women with abdominal wall endometriosis who underwent surgery to remove a lesion at the Assis Chateaubriand Maternity, Fortaleza, Brazil. From tissue blocks, histological sections were subjected to immunohistochemistry to identify ER, PR, and Ki-67. For statistical significance, an unpaired t-test was applied with a 95% confidence interval.

Results: The mean patient age was 30.4 ± 1.13 years. ER expression in the epithelium and stroma had a mean score of 33.45 and 17.14, respectively, and the difference was not significant. PR had a mean epithelial score of 175.71 and a mean stromal score of 72.29, significantly different (p = 0.0339). Ki-67 had epithelial and stromal scores of 14.14 and 12.14, respectively, which were not significantly different.

Conclusions: Abdominal wall endometriosis presents ER and variable PR expression in the epithelium and stroma. The Ki-67 marker demonstrated a reduced proliferation index.