Trying to understand axillary nodes

AMLMom

Hello, I was recently diagnosed with 1cm high grade comedo necrosis DCIS by mammo in the upper outer quadrant. There was a second more loosely grouped area of calcifications that hasn't been tested. Given my age (45), dense tissue, and second area, a pre-operative MRI was ordered. I was expecting perhaps more DCIS or perhaps indication of invasive cancer, but I was a bit taken aback by the fact that the report referred to an additional clumped and linear non-mass enhancement measuring at least 7.5cm with prominently progressive and some plateau kinetics. They want to test this area with US and another biopsy. Am I right to assume that this is more DCIS? I assume invasive cancer would present as a mass?

More importantly (I think?), a single rounded lymph node was seen in the left lower axilla. I have read a lot about DCIS but I know nothing about lymph nodes other than I read that a rounded shape has a PPV for malignancy.

Does anyone have experience with a rounded axillary lymph node? Even if it does turn out to show malignancy, what does that mean for treatment and prognosis?

I would remiss not to mention the good news. The staining of my original biopsy showed no indication of invasion and the second area of calcification was seen to be less suspicious on the MRI, so biopsy of that area can be deferred if it would affect surgical management (although admittedly I don't know exactly why it would).

I received these results via on-line portal and haven't discussed with my doctors yet (although I know what they're thinking in terms of tests needed because notes from their team discussion were posted to the portal this morning.

Any comments on the NME or round node would be much appreciated.

Thank you as always,