How would you approach diagnosis of residual ovarian tissue in a patient with ER positive breast cancer, history of BSO, and a rising estradiol level on tamoxifen?  

Diagnosing elevated estrogen levels in a patient who has undergone BSO is difficult, since the symptoms are typically very non-specific (e.g., improvement in hot flashes, change in mood). There are multiple potential reasons for elevated estrogen levels following BSO, including an adrenal tumor that...