Is a 5mm adenocarcinoma (pre-cancerous rectal polyup,)cause for immediate concer!
Question: I had one removed from my rectum when a colonoscopy was done. When I had a sigmoidoscopy 3 years earlier, nothing was found. The doctor wants me to go back yearly now and told me that I'm considered a "high risk" patient.
Had I not had this removed (it was causing bleeding problems, which is why I had this done,) how long would it have taken to turn into cancer?
Answers: I had one removed from my rectum when a colonoscopy was done. When I had a sigmoidoscopy 3 years earlier, nothing was found. The doctor wants me to go back yearly now and told me that I'm considered a "high risk" patient.
Had I not had this removed (it was causing bleeding problems, which is why I had this done,) how long would it have taken to turn into cancer?
Adenocarcinoma
The appearance of adenocarcinoma on barium studies varies with location. In the duodenum, 75% of adenocarcinomas appear as polypoid masses. Other appearances include infiltrative or stenotic lesions with or without ulceration. The upper GI series has a reported accuracy of 70 - 80% for detection of duodenal malignancies. If substances such as glucagon are administered during the upper GI series, the accuracy can be increased to 85 - 90% by maximizing duodenal distention and decreasing peristalsis
. In a report of 67 patients with adenocarcinoma of the duodenum, the upper GI series diagnosed 88% of cases. In that study, the EGD diagnosed 89% of cases. The upper GI series is a useful complimentary study when combined with the EGD, especially if the entire duodenum is not visualized at endoscopy.
On barium studies, adenocarcinomas of the mesenteric small bowel (jejunum and ileum) classically appears as a focal area of luminal narrowing, fold destruction, and over hanging edges (apple core lesion) . The mass is typically rigid and will not compress. Ulceration may be present. If the lumen is narrowed significantly, small bowel obstruction will occur. However, not all apple core lesions in the small intestine are due to primary adenocarcinoma. Metastasis to the small bowel can have an identical appearance . Also, inflammatory diseases such as Crohn's disease can result in segmental areas of stenosis which may mimic the appearance of adenocarcinoma. Usually, however, there are other indications that Crohn's disease may be present, such as involvement of other segments of the gastrointestinal tract. Overall, lesions smaller than 2cm in diameter may be difficult to visualize with CT. These are better detected by small bowel series or enteroclysis .
In addition to the apple core appearance, adenocarcinoma may appear as a polypoid intraluminal or intramural mass, rarely resulting in intussusception. Differentiating this appearance of adenocarcinoma from other polypoid lesions can be difficult. Rarely, adenocarcinoma can appear as a subtle eccentric plaque-like lesion in the small bowel, which can be detected on enteroclysis.
On computed tomography, small bowel adenocarcinomas may demonstrate a variety of appearances . The tumor most frequently appears as eccentric or circumferential wall thickening (usually greater than 1.5cm) involving a short segment of the small bowel . This may result in an "apple core" appearance, similar to that seen with barium contrast studies. Although inflammatory diseases of the small bowel may also produce diffuse or segmental wall thickening, this usually does not exceed 1.5cm in thickness. Also, inflammatory or ischemic diseases of the small intestine can produce a halo of alternating high and low attenuation within the wall. This is characteristic of a non-neoplastic process.
In cases of adenocarcinoma of the small intestine, which produce significant wall thickening, there may be luminal narrowing and proximal obstruction. Ulceration has been reported to occur in approximately 40% of cases of small bowel adenocarcinoma. However, this is usually not as well demonstrated on CT as with barium studies. Adenocarcinomas can rarely present as polypoid masses which may result in obstruction or intussusception. On CT, adenocarcinomas may appear homogeneous in attenuation, or in cases of large tumors with ischemia and necrosis, may appear heterogeneous. Contrast enhancement of the tumor may also be demonstrated.
In addition to detecting the primary small bowel adenocarcinoma, CT may aid in tumor staging. CT is not able to resolve the individual layers of the bowel wall. However, it can delineate tumors confined to the muscular wall and distinguish these from tumors that extend into the adjacent mesenteric fat. Irregular tumor margins or stranding in the adjacent mesenteric fat are indications of local tumor invasion.. Also, obliteration of fat planes between bowel loops or between the bowel and adjacent structures are suggestive of local tumor extension. CT can detect enlarged mesenteric lymph nodes which may be involved with tumor. Based on the location of the primary tumor, the regional draining lymph nodes can be predicted. For instance, tumors involving the duodenum tend to involve the lymph nodes in the peripancreatic, gastroduodenal, pyloric, and superior mesenteric artery regions. Regional lymph node drainage for both the jejunum and the ileum occur along the superior mesenteric vessels, while the terminal ileum may drain into lymph nodes in the cecal and ileocolic regions. Typically, mesenteric nodes greater than 1cm in short axis diameter are suspicious for neoplastic involvement. However, the sensitivity and specificity of CT are limited due to the fact that even very small nodes may harbor malignancy and large nodes may simply be reactive.
CT is currently the imaging modality of choice for the detection of liver metastasis. To maximize the detection of metastasis to the liver, imaging should be performed during the portal venous phase of enhancement. This will maximize the detection of small low attenuation lesions.
Staging of small bowel adenocarcinoma is based on the TMN system(Tables 1 and 2). This classification does not apply to lymphoma, sarcoma or carcinoid tumors.