Benign bowel tumors are rare clinical entities and they generally remain asymptomatic throughout life. They either develop as single lesions or multiple tumors of several subtypes. Benign bowel tumors include hyperplastic polyps, adenomas, GI stromal tumors, lipomas, hemangiomas and tumors associated with Peutz-Jeghers syndrome.
Such tumors are slow growing and may affect different parts of the gastrointestinal tract including duodenum, jejunum, ileum and colon. They grow inside the intestine (intraluminal tumors) or develop as infiltrative and serosal benign tumors. Intraluminal tumors are responsible for secondary bowel obstruction and intussusception and serosal lesion may lead to volvulus.
Clinical Characteristics of Benign Bowel Tumors
As it has already been mentioned benign bowel tumors are most commonly asymptomatic. In case there are symptoms and signs of the disease they include loss of appetite, early satiety, nausea, vomiting, diarrhea, constipation, melena and GI hemorrhage. Some of the potential complications associated with benign bowel tumors are volvulus, obstruction, anemia, intussusception and bowel perforation. Large tumors may be palpated as huge masses in the abdomen.
Types of Benign Bowel Tumors
Hyperplastic polyps are benign mucosal growths that generally affect the duodenum and proximal ileum. These tumors are either single or multiple and are usually asymptomatic. Hyperplastic polyps never transform into malignant tumors and can be successfully removed endoscopically with biopsy forceps or an Endosnare.
There are several subtypes of adenoma, one more group of benign tumors of the intestine. They include adenomatous polyps, Brunner gland adenomas and villous adenomas. These tumors may cause obstruction, bleeding, intussusception and in some cases malignant degeneration.
Gut stromal tumors are most common small bowel tumors that produce symptoms. They develop in a form of intraluminal masses, extraluminal masses or transmural lesions. In some cases the tumor may develop surface ulceration and/or deep necrosis and in such patients bleeding and marked hemorrhage develop as the most common complications. Apart from bleeding these tumors are responsible for obstruction, intussusception, tumor perforation and potential malignant degeneration.
Lipomas are benign submucosal tumors that predominantly develop in the ileum. Only if they grow large enough they cause colicky abdominal pain and intermittent bowel obstruction or itussusception.
Hemangiomas are vascular tumors and they rarely affect the intestine. There are several subtypes of hemangiomas and they include capillary, cavernous and mixed hemangiomas. These tumors in majority of cases cause intestinal bleeding and are also connected with obstruction, intussusception, formation of intramural hematoma and perforation.
Tumors associated with Peutz-Jeghers syndrome are benign gastrointestinal hamartomas. These tumors are located in the small intestine in almost 90% of all patients. Even the stomach and colon are frequently affected and the tumor may develop outside the gastrointestinal tract. Such tumors develop as a consequence of mutation on the LKB1 gene (19p2,3). Secondary complications develop in case there are multiple hamartomas in the gastrointestinal tract. They include colicky abdominal pain, gastrointestinal bleeding and obstruction and in some cases the tumor may undergo malignant alteration.