Endometrial Fluid found in ultrasound

[Deligirl1]

Recently had transvaginal ultrasound, came back with endometrial fluid, just had endometrial biopsy and DNC.  Dr told me fluid in cavity was not a good thing to have and is a sign of uterine cancer.  Well you can believe I am scared and need to wait 10 days for results.  Can theis fluid be cause by anything else besides cancer?  History: endometriosis, 4 yrs; multiple cysts over yrs, pass with menstration, "fibroid changes form last unltrasound, enlarged uterus for 10 months, shown on last two ultrasounds(10/2007, 7/2008)  Fluid was found on this last one 7/2008.  38 yrs old, premenopausal, have two little girls, ages, 7 and 4, on YAZ to help control endometrial pain and periods for about 1 yr now.  Please advise on any other conditions that may cause this fluid  -thank you so much for any guidance or information..