Relax, I can tell you exactly what is going on. Had the same situation in the summer. The gyn feels the lump, says it's probably a cyst but also says that they check out any lump and sends me for mammogram right away. The mammography did not (!) pick up the cyst (as they often don't). The radiologist says that it is a good sign, because mammograms often don't show cysts. So to confirm it is the cyst, they do an ultrasound, which EASILY picks up the cyst (because it is fluid filled, it shows on the ultrasound). So the radiologist puts the ultrasound thing on my breast and immediately confirms that it is a normal looking cyst with no further concern. That's why they do the ultrasound. They can confirm the diagnosis (which they can't by mammogram). They can also tell the difference between a simple and a complex (not only fluid in it) as well. If that is the case, they will watch it. Mine wasn't even followed up. And it disappeared within two months.
So, there is nothing - absolutely nothing - suspicious in the fact they do an ultrasound. In fact, any lump is always looked at with both tools.
- I am a fellow hypo and of course what happened was, that when the radiologist told me that it was 100% a cyst and I felt this huge relief, she said "I do see some calcifications on the mammogram though, that I want you to follow up with your imaging center at home (I was out of town when I found the lump). They need to compare our images to your old ones... don't worry, but if they are new calcifications, you'll need a biopsy..". Great - I was in panic for 4 weeks until I saw the radiologist at home who looked at both film and confirmed it was fine.... It always happens to us, doesn't it?