Polyp Sessile

Polyps may lake two forms. They can occur with stalks or without stalks (Haggitt et al, 19fJ5). Polyps, or adenomas, with stalks are called peduncvlated. while those without stalks are called sessile (Figure 11,1), When discovered in the doctor s... 

An uncontrolled retrospective study of patients who had taken proton pump inhibitors for an average of 33 months found gastric polyps in 17 of 231 patients who underwent two or more endoscopies for complicated gastro-esophageal reflux disease (33). The polyps were generally small (under 1 cm), sessile, and multiple, and were present in the proximal or mid gastric body. Of the 15 polyps removed endoscopically, nine were fundic gland type, four were hyperplastic, and two were inflammatory. None had any dysplasia or carcinoma. 

Mochizuka A, Uehara T, Nakamura T, et al. Hyperplastic polyps and sessile serrated adenomas of the colon and rectum display gastric pyloric differentiation. Histochem Cell Biol. 2007 128 445-455. 

Kawasaki T, Nosho K, Ohnishi M, et al. Cyclooxygenase-2 overexpression is common in serrated and non-serrated colorectal adenoma, but tmcommon in hyperplastic polyp and sessile serrated polyp/adenoma. BMC Cancer. 2008 8 33. 

Owens SR, Chiosea SI, Kuan SF. Selective expression of gastric mucin MUC6 in colonic sessile serrated adenoma but not in hyperplastic polyp aids in morphological diagnosis of serrated polyps. Mod Pathol. 2008 21 660-669. 

Fig. 7.1a-d. Multi-row CT colonography datasets showing a pedunculated (a, axial b, endoluminal view) and sessile (c, axial d, endoluminal view) polyp, located in the sigmoid colon... 

Fig. 19.6. Unfolded cube user interface in supine position showing the sessile adenomatous polyp (white arrow) that is displayed in Figure 19.2. In contrast to the (60° and 90°) conventional 3D display mode, the polyp is well detectable. Faces 2 and 4 represent a 90° view on the lateral sides of the colon face 1 represents the top side and face 6 the bottom side. In face 3 the frontal direction of view is displayed, and in face 5 the backward direction of view is displayed...

Types of papillomata were separated by Hodgson and Whitely into four morphologic groups (1) flat shiny lesions (2) sessile lesions resembling plantar warts (3) pedunculated skin tags (fibro-epithelial polyps) and (4) plaques (seborrheic keratoses). 

Fig. 4.8. Patient with right sided sigmoid. There is tagged stool (arrowhead). There is also non-tagged material (orrow). This should be considered a lesion unless the contrary is proved. A correct diagnosis of an 8-mm sessile polyp was made...

Fig. 4.15.a Ultra low dose scan (64-slice). Supine view of the rectum showing an 8-mm sessile polyp on the anterior border above a small level of tagged fluid, besides the first valve of Houston (black arrows). The valve of Houston is visible in the fluid as a linear Ailing defect. Small non-tagged residue in the fluid (open black arrowhead), c Corresponding endoluminal view. Despite the ultra low dose there are no streak artefacts. The polyp is easy to detect (black arrow) besides the first valve of Houston (black arrowheads)... 

Fig. 4.19.a Non-tagged foam with some tiny tagged residue besides a possible sessile polyp (black arrowhead) in the ascending colon (supine view), b Corresponding prone view the foam has moved to the anterior border of the ascending colon (white arrow). The sessile lesion remains unchanged (black arrowhead) and should be considered a sessile polyp. The lesion was confirmed on optical colonoscopy... 

Fig. 6.1a,b. Colonic phantom containing three different simulated lesions 9.6-mm and 5.5-mm sessile polyps and 8-mm flat lesion. Using a a thick collimation protocol lesions sharpness is definitely reduced compared with b a thin collimation protocol. Note edge blurring (arrow) directly related to the increase of effective slice thickness as well as geometric distortion. This artefact particularly affects simulated flat lesion (arrowhead)... 

Moreover, the degree to which partial volume effects distort polyp morphology is determined by polyp size relative to the effective section thickness and section sensitivity profile, which are primarily a function of collimation, pitch and interpolation algorithm. For SSCT protocols with 3 mm and 5 mm collimation and pitch ranging between one and two, excellent depiction of 6-mm and 13-mm pedunculated polyps and 10 3 mm sessile polyps can be... 

Fig. 6.4. Example of rippling artefacts induced by high pitch value. The small sessile polyp in a simulated colonic phantom (arrow) is barely seen...

Fig.7.3a,b. Polypoid lesions with focal pockets of air seen in true polyp vs stool, best shown in axial 2D MPR a true positive sessile polyp (arrow) with air around edges of lesion (arrowheads), where lesion abuts the wall b false positive of stool (arrow) with central pockets of air (arrowheads)... 

C-RADS describes the use of three morphologies of lesions sessile (broad based lesion whose width is greater than its vertical height), pedunculated (polyp with a separate stalk), and flat (polyp with vertical... 

Larger Flat Lesions 96 8.2.23 Small Sessile Polyps 96... 

Fig. 8.5a,b. False negative diagnosis polyps simulating fecal residue in mobile segments. Differential diagnosis of mobile stool or small sessile lesions in a mobile transverse colon a supine scan shows two lesions in the transverse colon, (arrows) b prone scan shows the lesions in the transverse colon in an apparent different position (arrows). Conventional colonoscopy revealed the presence of two small sessile polyps. Lesson Polyps, located in mobile colonic segments such as the transverse colon can cause erroneous diagnosis of mobile residual stool... 

Fig.8.7a-c. False negative diagnosis differentiate small sessile polyps located on the ileocecal valve from normal variations of the ileocecal valve. Although the ileocecal valve is an important mimicker of pathology, one has to keep in mind that polyps can arise on the ileocecal valve (arrows). Evaluation in a intermediate window setting as well as b abdominal window setting , combined with c 3D endolu-minal view are helpful to differentiate polyps from tumoral (see Fig. 8.9) or lipomatous transformation of the ileocecal valve (see Fig. 8.26). Lesson For the evaluation of pathology of the ileocecal valve, always use different window settings, in combination with endoluminal 3D evaluation...

Fig. 8.8. Small sessile polyp located in the ileocecal valve. Although most polyps are located on the ileocecal valve, polyps can also arise in the ileocecal valve (arrow)...

Although sessile polyps have a high conspicuity, if located between folds (Fig. 8.11), those lesions may remain undetected in case the lesions are located on a semilunar fold (Fig. 8.12). 

A thickened fold in an otherwise well distended colon might therefore point to the correct diagnosis of a sessile polyp on a haustral fold (Fidler et al. 2004) (see also Fig. 8.18). 

Fig.8.11a,b. Sessile polyp located between a haustral fold. Polyps located between normal haustral folds are easy to detect on a axial 2D image arrow), and b corresponding endoluminal 3D image (arrow)... 

First of all, there is the problem of insufficient awareness and familiarity with those lesions surveillance programs, based on the known adenoma-carcinoma sessile or pedunculated lesion, have mainly focused on identifying sessile of pedunculated polyps. This explains why flat lesions are frequently characterised as normal folds. As a rule, a thickened fold in an otherwise well distended colon should raise the question whether or not this lesion could represent a flat lesion. 

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