Estrogen receptor α plays an important role in Cushing's syndrome during pregnancy.

Cushing's syndrome (CS) during pregnancy is very rare with a few cases reported in the literature. Of great interest, some cases of CS during pregnancy spontaneously resolve after delivery. Most studies suggest that aberrant luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptor (LHCGR) seems to play a critical role in the pathogenesis of CS during pregnancy. However, not all women during pregnancy are observed cortisol hypersecretion. Moreover, some cases of adrenal tumors or macronodular hyperplasia with LHCGR expressed, have no response to hCG or LH. Therefore, alternative pathogenic mechanisms are indicated. It has been recently reported that estrogen binding to estrogen receptor α (ERα) could enhance the adrenocortical adenocarcinoma (ACC) cell proliferation. Herein, we hypothesize that ERα is probably involved in CS development during pregnancy. Better understanding of the possible mechanism of ERα on cortisol production and adrenocortical tumorigenesis will contribute to the diagnosis and treatment of CS during pregnancy.