Size of submucosal fibroid - mm or cm?

Hello,

In mid-Feb this year, I had a hystereoscopy to remove a 3cm submucosal/intracavity fibroid, and a laparoscopy to remove a small patch of endometriosis.

I had an ultrasound last week due to ongoing pelvic pain and discomfort, as well as my periods getting heavier since the operation. My recent period was heavy with clots. I thought these symptoms were due to a recent BV infection causing PID/Endometritis, for which I've just finished taking antibiotics.

I got the ultrasound results back the next day, which was unexpected, as I was told it would take around a week. The report says that I have a submucosal/intracavity fibroid measuring 2.7x2.3x2.6mm.

I'm wondering if it's possible for a fibroid that small to be detected, or

the sonographer has accidentally used mm instead of cm.

If the fibroid is as tiny as 2mm, then it's unlikely to have caused my recent heavy period, which could be due to PID/Endometritis instead. But if it's 2cm, then that would explain my symptoms. I have a feeling that it's cm and that's why I received the results so quickly, as this fibroid has grown very quickly at 2cm in 10 weeks. It's probably the same fibroid which was removed, but in the muscle at the time of the operation and has since pushed it's way into my uterine cavity.

I've got an appointment this week with the Gynae consultant who did my operation, so I can ask questions then, but I just wondered if anyone here could tell me if an ultrasound can detect a fibroid as small as 2mm? I can't find much info about this online and most of the measurements I've seen are in cm.

Thank you.