What is the biopsy in-depth extra test?

I have a lump, quite noticeable at the side of my left breast, near my chest muscle. (I do have large breasts). The lump was checked out 13 and 7 years ago and was told it was just how I was made. Noticed 6 months ago it was getting bigger. Saw GP at the beginning of December who immediately referred me to the hospital. Had an ultra sound, mammogram and biopsy all within an hour on the 21st Dec. The lump even though the consultant could feel it didn't show up on either the US or mammogram. Spoke to a breast nurse at the hospital today to get my results. She said they had sent my biopsy to a different lab for more in depth testing and that I was on the consultants list today for them to discuss the results. She said I will hear back within 7days. I don't understand what the in-depth tests are as surely the original biopsy test would say either I have or haven't got BC. I was feeling quite confident it wasn't bad but now I'm petrified it's BC. What is this in-depth test?

Dear Happily,

If only the world of pathology were so simple. Biopsies don't show just Yes or No to cancer, and even that question is not always straightforward. If you truly have a lump, then it's likely something that's not just normal breast tissue, but in the human body there are lots of different ways lumps can form from tissue that isn't just like its normal tissue surroundings. Scarring is probably the one easiest to understand. For example, smokers often have tons of "lumps" in their lungs that aren't cancer, they're just scars from past mini-infections.

Assuming it's not normal breast tissue, what it is ISN'T as simple as cancer vs. not-cancer. There will be a number of things that are definitely NOT cancer and have NO RISK of becoming cancer that are possible. There are some things that definitely ARE cancer that are possible. Then there's a category of things that have RISK OF BECOMING cancer. Also, there are things that look a lot like other things, and it's best to send to an expert in figuring those out. Lastly, sometimes it's hard to tell from the biopsy what exactly something is, for example if it's uncommon. Those last three possibilities require more thought than the first 2, and often require additional stains, so it takes longer to get a result. Sometimes the first lab needs to send to a more expert lab that has pathologists who are more specialized or for those extra stains to be done.

It's hard to wait, but hang in there.