Chapter 7f
RARE AND UNUSUAL SYNDROMES, POLYPOSIS SYNDROMES AND POLYPS
There are a number of rare or unusual syndromes mainly affecting the colon, some with some clinical interest, others mainly as oddities at endoscopy but of little clinical importance. It is proposed to review some of the most important or flamboyant of these entities. Why they are mainly colonic with the small intestine continuing its relative freedom from such abnormality is a topic worthy of discussion elsewhere.
1. PEUTZ-JEGHERS SYNDROME
This condition, well known to all senior medical students, is one they will probably never see in the flesh. It is due to an autosomal dominant condition characterised by hamartomas in the colon and elsewhere in the gut together with the unique perioral melanin pigmentation in nearly every patient. Multiple polyps occur anywhere in the gut, particularly the small bowel but also stomach, colon and rectum. Symptoms begin in the third decade from benign complications but by the fourth decade malignant changes affecting both GI tract and elsewhere develop. The condition is due to a defect on chromosome 19p, half the cases are familial and half apparently de novo. The incidence is about 1:120000 births.
2. NON NEOPLASTIC POLYPS OF THE COLON A variety of these are seen; by definition they are benign. Their significance is mainly in their separation from polyps with malignant potential. They include:
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• Hyperplastic Polyps. These are usually less than 5mm in diameter, mainly occur in the rectum, increase in number with age and remain benign.
• Inflammatory Polyps. These complicate the healing process of colonic ulceration, especially chronic ulcerative colitis but also Crohn’s disease and other chronic inflammatory disorders. Unusually they may develop malignant change.
• Juvenile Polyps. These hamartomas are not unusual in children and have no malignant potential. There is also a familial form, autodominant in origin which has malignant potential.
3. SUB MUCOSAL POLYPS These may be found in several rare situations:
• Colitis Cystica Profunda. This consists of mucus filled cysts often in the rectum resembling the standard colonic polyp but most often are a consequence of rectal prolapse or inflammatory bowel disease.
• Pneumatosis Cystoides Intestinalis. This consists of air filled cysts in the colon or small bowel producing bizarre appearances at endoscopy or radiology.
4. LAXATIVE SYNDROME
This may take two forms. The presence of either may alert the endoscopist or clinician to occult use of laxatives by the patient and clarify otherwise obscure symptom complexes.
• Melanosis Coli. This consists of a profusion of pigment laden macrophages in the mucosa to produce a strange reticulated pigmented pattern resembling alligator skin mainly in the rectum and caecum. Not rare, it follows enthusiastic use of anthroquinone laxatives – cascara, aloes, senna, rhubarb. It may appear within months and disappear as quickly on cessation of intake and be a manifestation of Munchausen’s Sydrome.
• Cathartic Colon. Follows the surreptitious abuse of cathartics, generally anthroquinone types nearly always by women with psychological disturbance for many years. It involves increasing use of purges leading to an atonic colon requiring increasing laxative use and may be associated with hypokalaemia, hypovolemia and even steatorrhoea. The diagnosis is made on the radiological appearance on a atonic dilated colon resembling chronic ulcerative colitis but
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RARE AND UNUSUAL SYNDROMES 97 with a normal colonic mucosa. It resolves in months on laxative cessation and again may be a manifestation of Munchausen’s syndrome.
5. NSAIDS AND THE COLON
There is abundant evidence that NSAIDs may produce major colonic injury. It is likely the mechanism is an impairment of cyclooxygenase activity in the mucosa as in the stomach and the changes are similar. There may be occult or overt bleeding, ulceration, perforation and even perforation of diverticula and it generally occurs in older females. Furthermore there is considerable evidence that NSAIDs may produce relapse of IBD in remission generally within a week of administration. Furthermore a link of NSAIDs with collagenous colitis has been speculated upon.
6. OTHER DRUGS AND THE COLON
There are reports of colonic ischaemic changes with a number of drugs including the OCP, alosetron, cocaine and amphetamines.
