1. Irritable Bowel Syndrome
Irritable bowel syndrome (IBS) is an important disease entity because of its high prevalence, substantial morbidity, and enormous costs. IBS is characterized by the presence of abdominal discomfort or pain associated with disturbed defecation. Bloating or visible abdominal distention often is present in patients with IBS but are not considered essential symptoms for diagnosis.
Rome III Criteria for DX:
Recurrent abdominal pain or discomfort at least three days/month in the last three months associated with two or more of the following:
1-Improvement with defecation 2-Onset associated with a change in frequency of stool 3-Onset associated with a change in form (appearance) of stoo
RX: reassurance and supportive according to symptoms.

2. Colonic Polyps and Polyposis Syndromes
A gastrointestinal polyp is a discrete mass of tissue that protrudes into the lumen of the bowel. Colonic polyps may be divided into two major groups: neoplastic (the adenomas and carcinomas) and non-neoplastic. The adenomas and carcinomas share a characteristic—cellular dysplasia—. The non-neoplastic polyps may be grouped into several distinct categories: hyperplastic polyps , juvenile polyps, inflammatory polyps, and others.
Polyp can be pedunculated (i.e., attached by a stalk) or sessile (i.e., attached by a broad base with little or no stalk).
Adenomatous polyp,histologically , can be tubular, villous or tubulovillous.
Malignant Potential of Adenomatous Polyps(risk of malignancy) :
1- size of polyp ( more than 2 cm)
2- histological type( villous more than tubular)
3- presence of dysplasia (mild-moderate-severe)

3. GASTROINTESTINAL POLYPOSIS SYNDROMES
Gastrointestinal polyposis refers to the presence of numerous polypoid lesions throughout the gastrointestinal tract.
Most of these syndromes are inherited, and most are associated with an increased colon cancer risk, but all are classified on the basis of the histologic type of polyp and the clinical presentation.
Familial Adenomatous Polyposis:
FAP is the most common adenomatous polyposis syndrome. It is inherited as an autosomal dominant disease. Classic FAP is characterized by the progressive development of hundreds to thousands of adenomatous polyps in the large intestine. Colorectal cancer should be considered an inevitable consequence in the natural history of FAP, appearing approximately 10 to 15 years after the onset of polyposis. polyps in the stomach and small intestine(especially periampullary) are present in almost all FAP patients.
DX: colonoscopy RX: proctocolectomy