Two types of cancer or metastasis

My mother has been diagnosed with recurrent IDC.  She had a lumpectomy and radiation in her right breast 15 years ago.  She now has 3.5mm mass in same breast.  After PET scan the doctor found cancer in bilateral lymph nodes.  Axillary lymph nodes were clear and left breast was clear also.  Could these be two different types of breastcancer that were found coincidentally since there is no clear path between them?  Could this be metastasis of primary tumor in right breast that has traveled to left lymph nodes?  Have you ever heard of this kind of thing happening before?  Doctor seemed puzzled with results also.  My mom is scheduled for bilateral mastectomies and bilateral sentinal node surgeries on Friday.  She is also ER-, PR-, and HER2-, could this have anything to do with these odd results?

[japdip]

It could be either one of those things. A PET scan shows areas of increased enhancement but can't really diagnose cancer. This would have to be confirmed by Pathology examination of the nodes when they are removed. Unless a biopsy of the suspected nodes was done then one couldn't be certain that they had been invaded by the cancer. Triple negative isn't the best news but it isn't unusual. Was your mother's tumor 15 yrs. ago triple negative also ? Wishing your Mother a successful surgery and uneventful recovery. Regards ....

[lori37]

The lymph nodes were biopsied and confirmed as cancer, I don't know if they could tell by the biopsy if it had the same characteristics of the cancer in the right breast.  My mom has also had uncontrollable shaking in her left arm on occasions.  They did a brain MRI and it came out clean.  Could this just be stress or should they be checking for spinal mets?  Would the PET scan have shown something on spine if it was there? (Scan was from bottom of skull to mid thighs).  She hasn't had a bone scan, would that show anything that a PET scan wouldn't show?  Thanks-

[japdip]

The PET scan would show enhancement in any area that it covered and the spinal area was included in your Mother's scan. All these tests,  MRI, PET, CT, Bone Scan see things in a different way. They are all valuable and at times are combined to get the optimum result. I can't see that the shaking would be related; especially if the Brain films were negative. This could be some entirely unrelated problem. It could be determined by Pathologic examination as to whether this is a recurrance or a new primary cancer. The only difference would be the part of treatment dealing with the ER/PR and Her2 positivity.Of course more information will come via Pathology after the surgery.     Regards ....