You may want to look FISH staining if this is not what you already had??
( not sure) . YOu can google it - my mother was positive for POLY cells vs. mono cells ( trisomy 7, I think). I know brushingscan be sent to the Mayo for FISH analysis because not all hospitals do this testing themselves. Also how is the CA 19-9 reading? Not sure if both types of cancer can be identified through these numbers. Unfortuantley CC is determined by a combination of tests, namely CA 19-9 ,FISH staining, brushings, in combo with a visible tumor. (although some CC is cellular with no tumor). Normally a needle biopsy is not done as it has been known to seed the cancer.
Lastly, not sure where you are, but the Mayo has a branch in florida as well as Arizona and Minnesota. the application process you read was unfortunate but I think it may have applied to a patient from Canada? We called Minnesota , got an appt and were never asked for any $, period. I know others on this site have been in contact via email with doctors there but even it you can get an email address you still have to have a doc send the brushings.
So, I would think your doctor could contact MAYO and send out the brushings for FISH staining and this will help you narrow your diagnosis? I can understand your frustration - hang in there.