Hi - my cancer was detected in the lymph nodes - two were enlarged. After CTs, PET CTs and MRIs no primary was found but through a process of elimination the breast was the prime suspect - though no lump or cancer detected.
Evidently it can happen that the breast can produce the cancer cells then stop and whatever it was that was producing disappears. But it could at any time reappear and start producing again.
With that in mind and discussion with surgeon and BCNs I opted for mastectomy and full node clearance. Now 6 weeks post op and no spread into other lymph nodes - seeing oncologist on Thursday for chemo plan - I believe it’s a belts and braces measure.
I’d love to hear from anyone else who has this experience- I think it’s referred to as CUP (cancer from an unknown primary) . It’s slightly unnerving but have total faith in the wonderful surgeon and BCNs
Thank you for reading 
Hi @julieytey 
I hope someone with a similar experience can get back to you on this, just wanted to send love and hugs in the meantime 
I hope you’re finding good support in your team and with friends and family, we’re all here for you too! I hope you’re keeping as well as you can even through this stressful time 
CUP can definitely feel unsettling since there’s no clear starting point, but it’s really encouraging to hear how thorough your team has been and that your nodes were clear beyond the two. Going for the mastectomy and full node clearance sounds like a strong choice given the unknowns, and I hope your upcoming oncologist visit gives you a solid, reassuring plan going forward.
You’re not alone in this, and your story could really help others in the same situation feel less in the dark
Thank you 
Hi. I was like you with just a lump in the armpit which turned out to be triple negative breast cancer. I had mammogram, CT scans, MRI scan and PET scan but nothing showed in my breast on any of them! I had chemo immunotherapy then a mastectomy. Lo and behold they found a tumour bed - the tumour had gone thanks to the treatment and I also had DCIS intermediate! Hope you are making a good recovery! 