Ectopic endometriotic tissue uniquely expresses the enzyme aromatase, which is absent in normal eutopic endometrium. This local aromatase activity contributes to endometriosis pathogenesis primarily through which mechanism?

• A Activation of macrophages causing fibrosis
• B Progesterone receptor downregulation causing progesterone resistance
• C Increased prostaglandin synthesis causing pain
• D Local conversion of androgens to estradiol, promoting lesion growth ✓

Explanation

Aromatase (CYP19D1) is aberrantly expressed in endometriotic stromal cells but absent in normal endometrium. It converts circulating androgens to estradiol locally, creating a hyperestrogenic microenvironment that promotes lesion growth and inflammation. This is the rationale for using aromatase inhibitors (letrozole) in refractory endometriosis. Progesterone resistance and prostaglandin excess are downstream effects, not the direct result of aromatase.

Reference: Comprehensive Gynecology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.