Uterine biopsy not enough tissue extracted: Now What?

I am post menopausal (72) and had vaginal discharge and spotty bleeding. Ultrasound early this month showed Endometrial thickness of 15 mm and a small 0.6 cm hyperchoic avascular lesion surrounded by fluid. Though I requested a hysteroscopy so that the lesion could be removed and tested (as was recommended on the ultra sound report), my gynecologist said the first step needed to be in-office ultra sound guided endometrial biopsy.

During the procedure, I asked if the lesion would be removed , she indicated it might or might not be, but she would concentrate in that area for removal of tissue. A week later, she called and said "no cancer is seen", but when I asked her to actually read the report to me, she admitted that no cancer was seen because there was not enough tissue retrieved at the biopsy to actually test ("No definitive endometrial tissue identified"....so the biopsy was "inconclusive" and she did not know if the lesion was still there or not!

So, now I am left with no more information than I had before and the additional worry that the lesion may or may not be available for testing at this point! She suggested waiting to see if spotting re-occurs and said my chances of actually having cancer were tiny, but if I'm one of the 1% who actually have it, that is no satisfactory answer! What should be my next step?