Congratulations and I hope you see continued progress. As you say, you are not sure what you have. Could be that laetrile (apricot seeds) have been responsible, though normally laetrile is fairly slow acting. Just a thought: you might try adding some inositol/IP6 and colloidal silver - as that combo seems to be a good one for eliminating tumors/tumor like masses. If it were me, I would also consider curcumin and N-Acetyl Cysteine as well as changes to a healthy diet and lifestyle if needed. And if you do get a definite diagnosis of cancer, there is more still you may wish to do.
I will say one thing: do not rely on apricot seeds alone for your mother-in-law. Laetrile has been widely ballyhooed - and I like it - but the reality is that, while it can be effective, it is far from universally effective and most studies which found effectiveness found that it was most effective when used in combination with other cancer fighting items, such as supplements, diet, lifestyle, etc.
I'm not sure how kernels worked for me (apricot pits that is) - I don't have anything I know of to use them for, but I have munched on them several times off and on, Kinda tasty lil devils . . .