From 2006 to 2016 there were 12 studies in Algeria (breast, thyroid, large B-cell lymphoma, renal, gastric, head and neck, nasal, and rectosigmoid junction
), 1 study in Libya (liver), 2 studies in Malawi (Burkitt's lymphoma), 3 studies in Nigeria (breast), 23 studies in Tunisia (breast, lungs, nasal, gastric, prostate, renal, head and neck, pancreatic, and rectosigmoid junction
), and 1 study in Zimbabwe (cervical).
To examine colorectal cancers by anatomic subsites, we classified cancers of the ascending colon, hepatic flexure, transverse colon, and splenic flexure (ICD-O-3 codes C18.0, C18.2-C18.5) as being right-sided; cancers of the descending and sigmoid colon (ICD-O-3 C18.6-18.7) as left-sided; and cancers of the rectosigmoid junction
(ICD-O-3 C19.9) and rectum (ICD-O-3 C20.0) as rectosigmoid.
The imaging diagnosis is based on: (i) a vertical dense white line on abdominal film, signifying apposed inner walls of sigmoid colon pointing towards the pelvis; (ii) gas in the proximal large bowel with no gas in the rectum; (iii) inverted U-shape of the sigmoid colon with absent haustra; (iv) the 'northern exposure' sign--dilated twisted sigmoid colon projecting above the transverse colon on a supine abdominal film; (v) apex of the sigmoid volvulus above T10 vertebra and under the left hemidiaphragm; and (vi) 'beaking' seen in the distal sigmoid colon with contrast enema--smooth tapered narrowing or point of torsion at the rectosigmoid junction
The biliary stent had migrated into the distal sigmoid colon just proximal to the rectosigmoid junction
. Additionally, the stent had lodged itself into and perforated through a sigmoid diverticulum.
He underwent surgery because oral and intravenous contrast-enhanced abdominal tomographs revealed perforation proximal to the rectosigmoid junction
, associated with extensive intra-abdominal free fluid and free air (Fig.
Colonoscopic examination showed an unusual polypoid tumor with stenosis of the lumen at the rectosigmoid junction
, but endoscopic biopsy showed only nonspecific inflammation.
12 of the 13 cases of perforation occurred in the sigmoid colon, rectosigmoid junction
or the rectum, which constitute the area of investigation of rectosigmoidoscopy.
 Here we present an interesting case of primary colorectal lymphoma involving the rectosigmoid junction
, rectum and anal canal.
The rectosigmoid junction
is the first part of colon that cannot stand higher pressure while anus, distal rectum are supported with pelvic structures.