Benign Pancreatic Tumor at Head of Pancreas

Hi, I have kind of a specific question. In November 2004, I had an MRI taken of my stomach for chronic nausea. When we were notified of the results we were told that my stomach looked fine, however, a large mass at the head of my pancreas was found. My dad is a doctor and we had had one of his friends order the MRI. They were unable to get ahold of us for a few days, and wanting to get in touch quickly, they ended up leaving a voicemail which my mother got one morning. In the voicemail, they said that they had found a large mass at the head of my pancreas, and I needed to come in soon. My mother then went up to my father who was getting ready and, without mentioning my name, she asked, "What does it mean when someone is told by the doctor they have found a large mass at the head of their pancreas?" My father, not knowing who she was talking about, said, "Well, pretty much means they are 6 feet under in 6 months depending on the circumstances." My mother then told him that that was my diagnosis, and they both proceeded to freak out. At the time, of course, my parents did not let on at all about how serious my condition was (I was 17 years old). I then immediately went in to get a biopsy done. It was negative for cancer! Before I went in for surgery, we did not know exactly how the tumor was located on my pancreas. If it was spread out over lots of areas, I would need a Whipple procedure. If it was not, they would just remove the needed areas. It turns out, it was about the size of a hacky sack and very compact, so a Whipple was not needed either! I lucked out in every sense. Since I was left out of the loop a lot during this time about the severity of my condition, etc. I am now a lot more curious as to the rarity of my situation. I do know that my doctor said that my case would be written up in some medical book, and that they needed the tumor for research.

QUESTION: I was wondering if anyone knows what the percentages are of a tumor being cancerous if it is found at the HEAD of the pancreas. Obviously, the percentage of a tumor being benign if found at the head of the pancreas works too. I have searched both online and have been unable to find the answer. Thanks!