Estrogen receptor-beta expression in extraabdominal fibromatoses - An analysis of 40 cases

BACKGROUND. Early experiments using ligand-binding assays demonstrated the presence of estrogen receptor (ER) in fibromatoses. These findings were not confirmed by later studies using immunohistochemical analysis. METHODS. To verify the expression of Ells in fibromatosis as well as to clarify the inconsistency between radioligand and early immunohistochemical studies, the authors examined a series of 40 extraabdominal fibromatoses using antibodies raised against ERP. RESULTS. All 40 cases of extraabdominal fibromatosis were at least focally positive for ER beta. Thirty-three of 40 (83%) displayed 3+ (> 50%) expression, 5 of 40 (12%) were 2+ (11-50%), and 2 of 40 (5%) cases showed 1+ (< 10%) expression. All cases were negative for ER alpha. CONCLUSIONS. Although extraabdominal fibromatosis does not express ER alpha, there appears to be nearly uniform expression of ERP. This finding clarifies discrepancies in the literature regarding estrogen expression in fibromatosis, and provides a biological mechanism for the action of antiestrogenic compounds in the treatment of fibromatosis. Estrogen antagonists may have a role in the treatment of refractory or recurrent extraabdominal fibromatoses.