Sigmoid carcinoma

Fig. 13.14a,b. Semicircular sigmoid carcinoma (arrow) focal, asymmetric, semicircular wall thickening with shoulder formation in the sigmoid colon (a,b). The lesion shows CM enhancement and pericolic soft tissue stranding (b)... 

Extraperitoneal perforation and leakage of barium may cause few immediate symptoms, but delayed endo-toxic shock can develop some 12 hours later, often causing death. Bowel infarction can also result. Barium granulomata can occur, causing painful masses, rectal strictures, or ulcers. On proctoscopy, an ulcer with a whitish base can mimic a carcinoma. In one rare case, perforation of a barium enema into a sigmoid abscess was followed by intravasation into the portal venous system (11). 

Direct invasion in T4 includes invasion of other segments of the colorectum by way of the serosa for example, invasion of the sigmoid colon by a carcinoma of the cecum. 

Fig. 3.7. a Collapse of a long length of the sigmoid on coronal multiplanar reformatted view simulating annular carcinoma, b Occlusion of the lumen on endoluminal view due to collapse of the sigmoid in the same patient. This appearance may also be caused by an occluding carcinoma, and proper colonic distension is essential for differentiation... 

Figure 8. (A) Influence of sample size on the heat output per cell in a suspension of human renal carcinoma cells. Note that it decreases with increasing cell number. This may be expressed by a continuous transition from aerobiosis in a monolayer-like suspension to increasingly anaerobic conditions in a crowded ampoule. (B) Influence of sample size on heat output per unit dry weight (dw) in rat liver tissue samples. It increases with decreasing sample size. This is apparently due to a continuous transition from mainly anaerobic conditions in large tissue slices to an increasing amount of aerobiosis in biopsy -Iike samples. The two curves complement each other giving a sigmoidal relationship, whose steep portion fits a linear regression when plotted on log scales (Reproduced from Reference [43] with permission).

A 77-year-old man who had been taking orphenadrine 150mg/day for one year developed urinary retention for which he had transurethral prostatectomy. Two years later he presented with intestinal obstruction suggestive of carcinoma of sigmoid colon. Investigation showed impacted faeces only (55 ). 

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