Colitis? Colon Cancer?

Hello,
I am a 30 year old male. I alwayd had some digestive problems, such as frequent diarheea and difficulty eating fruits and vegetables. Lately it seemed to become worse.  My stool is sometime  smalll and hard and sometime soft. My stool comes out in many pieces usually and seems to be rather flat lately.(I did buy one of those take home kits for detecting blood in the stool and it turned up to be negative). I do have a lot of gas and feel bloated most of the time.

Anyway, I had some lower abdominal pain lately, especially in the right hand side. Due to this symptom and my flat stool, the doctor send me to do a CT scan with contrast. Here are the main findings

- there are subcentimeter mesenteric nodes, none large enough to be considered pathological;
- the rectosigmoid colon is not filled with contrast:it does, however, have a somewhat tacked down appearance with a persistent narrow lumen throughout. The radiologist is concerned about possible pathology involving the rectosigmoid colon such as colitis.
- the rectum also gives the appearance of slight thickening of the wall though with the the absence of oral contrast filling that region, he cannot exclude that being completely artifactual
- there are some prominent inguinal lymph nodes present, the largest measuring approximately 8-9 mm in short axis

Now I read the report and I become really worried. Is it possible that I have colon cancer? It says that the lumen is narrow throughout the rectosigmoid colon, which is pretty long, so could that be a tumor? Or a tumor would look different at the CT scan and would involve only a smaller piece of the colon? Are colon tumors actually visible on a CT scan?

Also, does a colitis lead to a narrowing of the whole rectosigmoid colon? How about the slightly enlarged lymph nodes? Could they have anyrhing to do with something like colitis or is that a sign of cancer?

I am really concerned and I will see a GE in 2 weeks.

Thank you

[boron]

Colorectal cancer has very uniform look. It mostly started as a benign polyp, which protrudes into intestinal hollow. It could also appear as an ulcer. This could be seen both on CT or x-ray with barrium, but for final diagnosis of cancer colonoscopy with biopsy of the tumor would be neded. Colonoscopy would also confirm/exclude mst of other changes, like stenosis etc.