Gastrointestinal intraepithelial neoplasia (GIN or GIIN) is also known as gastrointestinal dysplasia. Gastrointestinal dysplasia refers to abnormal growth of the epithelial tissue lining the gastrointestinal tract including the esophagus, stomach, and colon. Pancreatic, biliary, and rectal Intraepithelial Neoplasia are discussed separately. The regions of abnormal growth are confined by the basement membrane adjacent to the epithelial tissue and are thought to represent pre-cancerous lesions.
In the GI tract, tumor progression is thought to occur in a series of steps. [1] It begins with normal tissue and long-term inflammation causes the cells to undergo atrophy, metaplasia, dysplasia, and finally, becomes an adenoma or carcinoma. [2] Given this progression, these lesions represent a potentially cancerous growths and an important opportunity to prevent gastrointestinal cancer.
Cancers of the GI tract (esophageal, gastric, and colorectal) are on the rise. Over the last 30 years there has been an increase in incidence of adenocarcinoma of the esophagus, gastroesophageal junction, and gastric cardia. [3] Gastric cancer is the fourth most common malignant tumor and third most common cause of cancer related death. When gastric cancer is caught early, the five year survival rate is estimated to be around 90%. [4] [5] However when diagnosed at an advanced stage, survival falls to less than 30%. Colorectal cancer has demonstrated an increasing incidence in younger populations with the US lifetime risk estimated to be about 4%. [6] Colorectal cancer is the second most common cause of cancer related deaths with the highest burden found in Australia, New Zealand, Europe, and North America. [7] [8]
Signs and symptoms vary based on the location of the tumor and as this is a pre-cancerous stage, many patients are asymptomatic. Symptoms associated with all types of GI cancers include weight loss, abdominal pain, and anemia. Specific symptoms include:
Esophageal lesion:
Gastric lesion:
Colorectal lesions:
Risk factors also vary significantly based on the location and type of tumor. Risk factors for esophageal cancer include GERD, obesity, excessive alcohol use, and smoking. Other risks identified include high temperature foods, exposure to polycyclic aromatic hydrocarbons, and esophageal dysbiosis. [3] [12] [13] [14]
Risks for gastric cancer include chronic gastritis or inflammation. This can be caused by H Pylori infection, autoimmune gastritis, [15] high salt diet, and smoking. [16]
Colorectal cancer risk increases with increased consumption of red meat, low fiber diet, alcohol use, and obesity. A number of conditions may also increase your risk of colorectal cancer such as irritable bowel disease, familial adenomatous polyposis, lynch syndrome, and cystic fibrosis. [3]
Diagnosis of these lesions is made through histologic examination of tissue samples obtained via endoscopic biopsy. When examining the samples, the histologist looks for evidence of dysplasia which is defined as “unequivocal neoplastic epithelium confined to the basement membrane”. [17]
According to the WHO classification of Digestive System Tumors, these lesions are classified based on a two tier system. [18] The two tiers or classifications are low or high grade dysplasia. Low grade dysplasia means that the tissue maintains the glandular structure, cellular variance (pleomorphism) is mild or absent, nuclei maintain basal polarity and mitotic activity is not markedly increased. Where as high grade dysplasia includes features such as complex glandular architecture, marked deviation from the cells typical appearance (unusually large nuclei with prominent nucleoli), loss of typical cellular structure, and frequent mitotic figures.
The Paris Classification system, established in 2002, is used to classify superficial neoplastic lesions of the gastrointestinal tract based on their endoscopic appearance. This system of classification is clinically significant as it enables estimation of the depth of tumor invasion. [19]
Type | Description | Subclasses |
---|---|---|
1 | Polypoid | p: protruded, pedunculated s: sessile |
2 | Nonpolypoid | a: slightly elevated b: flat c: slightly depressed |
3 | Excavated |
The Vienna classification of gastrointestinal neoplasia was published in 2000 in an attempt to resolve differences in diagnoses between Eastern and Western trained pathologists. This system utilizes cytology, depth of invasion, and architectural severity. [20]
Category | Classification | Subclasses |
---|---|---|
1 | Negative for neoplasia/dysplasia | |
2 | Indefinite for neoplasia/dysplasia | |
3 | Non-invasive low grade neoplasia (low grade adenoma/dysplasia) | |
4 | Non-invasive high-grade neoplasia | Category 4
|
5 | Invasive neoplasia | Category 5
|
The classification system commonly used to classify early gastric cancers was established in 1998 in Japan. This system utilizes visual and endoscopic features for classification and was developed to better assess which lesions were at higher risk of invasion. [21]
Type | Type | Subclasses |
---|---|---|
1 | Polypoid/protuberant | 1p: pedunculated 1ps/sp: Subpedunculated 1s: sessile |
2 | Flat | 2a: superficial elevated 2b: flat 2c: flat depressed |
3 | Ulcerated | |
4 | Lateral spreading tumor |
Gastroenterology is the branch of medicine focused on the digestive system and its disorders. The digestive system consists of the gastrointestinal tract, sometimes referred to as the GI tract, which includes the esophagus, stomach, small intestine and large intestine as well as the accessory organs of digestion which include the pancreas, gallbladder, and liver.
Barrett's esophagus is a condition in which there is an abnormal (metaplastic) change in the mucosal cells lining the lower portion of the esophagus, from stratified squamous epithelium to simple columnar epithelium with interspersed goblet cells that are normally present only in the small intestine and large intestine. This change is considered to be a premalignant condition because of its potential to further transition to esophageal adenocarcinoma, an often-deadly cancer.
Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum. Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, abdominal pain and fatigue. Most colorectal cancers are due to old age and lifestyle factors, with only a small number of cases due to underlying genetic disorders. Risk factors include diet, obesity, smoking, and lack of physical activity. Dietary factors that increase the risk include red meat, processed meat, and alcohol. Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases. It typically starts as a benign tumor, often in the form of a polyp, which over time becomes cancerous.
Esophageal cancer is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include difficulty in swallowing and weight loss. Other symptoms may include pain when swallowing, a hoarse voice, enlarged lymph nodes ("glands") around the collarbone, a dry cough, and possibly coughing up or vomiting blood.
Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymphomas and mesenchymal tumors may also develop in the stomach. Early symptoms may include heartburn, upper abdominal pain, nausea, and loss of appetite. Later signs and symptoms may include weight loss, yellowing of the skin and whites of the eyes, vomiting, difficulty swallowing, and blood in the stool, among others. The cancer may spread from the stomach to other parts of the body, particularly the liver, lungs, bones, lining of the abdomen, and lymph nodes.
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs arise in the smooth muscle pacemaker interstitial cell of Cajal, or similar cells. They are defined as tumors whose behavior is driven by mutations in the KIT gene (85%), PDGFRA gene (10%), or BRAF kinase (rare). 95% of GISTs stain positively for KIT (CD117). Most (66%) occur in the stomach and gastric GISTs have a lower malignant potential than tumors found elsewhere in the GI tract.
A neoplasm is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed. This abnormal growth usually forms a mass, which may be called a tumour or tumor.
A precancerous condition is a condition, tumor or lesion involving abnormal cells which are associated with an increased risk of developing into cancer. Clinically, precancerous conditions encompass a variety of abnormal tissues with an increased risk of developing into cancer. Some of the most common precancerous conditions include certain colon polyps, which can progress into colon cancer, monoclonal gammopathy of undetermined significance, which can progress into multiple myeloma or myelodysplastic syndrome. and cervical dysplasia, which can progress into cervical cancer. Bronchial premalignant lesions can progress to squamous cell carcinoma of the lung.
Gastrointestinal cancer refers to malignant conditions of the gastrointestinal tract and accessory organs of digestion, including the esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The symptoms relate to the organ affected and can include obstruction, abnormal bleeding or other associated problems. The diagnosis often requires endoscopy, followed by biopsy of suspicious tissue. The treatment depends on the location of the tumor, as well as the type of cancer cell and whether it has invaded other tissues or spread elsewhere. These factors also determine the prognosis.
Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia, is the abnormal growth of cells on the surface of the cervix that could potentially lead to cervical cancer. More specifically, CIN refers to the potentially precancerous transformation of cells of the cervix.
A colorectal polyp is a polyp occurring on the lining of the colon or rectum. Untreated colorectal polyps can develop into colorectal cancer.
Epithelial dysplasia, a term becoming increasingly referred to as intraepithelial neoplasia, is the sum of various disturbances of epithelial proliferation and differentiation as seen microscopically. Individual cellular features of dysplasia are called epithelial atypia.
An inflammatory fibroid polyp(IFP) is an uncommon digestive system tumor. J. Vanek initially identified it as a separate pathological entity in 1949 when he reported six case reports of eosinophilic infiltration in gastric submucosal granulomas. It is a single, non-encapsulated polypoid lesion that is typically submucosal. It is characterized by a large number of small blood vessels, oedematous connective tissue, and an inflammatory eosinophilic infiltrate.
Chromoendoscopy is a medical procedure wherein dyes are instilled into the gastrointestinal tract at the time of visualization with fibre-optic endoscopy. The purposes of chromoendoscopy is chiefly enhance the characterization of tissues, although dyes may be used for other functional purposes. The detail achieved with chromoendoscopy can often allow for identification of the tissue type or pathology based upon the pattern uncovered.
Endoscopic mucosal resection is a technique used to remove cancerous or other abnormal lesions found in the digestive tract. It is one method of performing a mucosectomy.
Field cancerization or field effect is a biological process in which large areas of cells at a tissue surface or within an organ are affected by carcinogenic alterations. The process arises from exposure to an injurious environment, often over a lengthy period.
Oesophagogastric junctional adenocarcinoma is a cancer of the lower part of the oesophagus with a rising incidence in Western countries. This disease is often linked to Barrett's oesophagus.
The term squamous-cell carcinoma (SCC), also known as epidermoid carcinoma, comprises a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the lining of the respiratory and digestive tracts.
The histopathology of colorectal cancer of the adenocarcinoma type involves analysis of tissue taken from a biopsy or surgery. A pathology report contains a description of the microscopical characteristics of the tumor tissue, including both tumor cells and how the tumor invades into healthy tissues and finally if the tumor appears to be completely removed. The most common form of colon cancer is adenocarcinoma, constituting between 95% and 98% of all cases of colorectal cancer. Other, rarer types include lymphoma, adenosquamous and squamous cell carcinoma. Some subtypes have been found to be more aggressive.
Confocal endoscopy, or confocal laser endomicroscopy (CLE), is a modern imaging technique that allows the examination of real-time microscopic and histological features inside the body. In the word "endomicroscopy", endo- means "within" and -skopein means "to view or observe". CLE, also known as "optical biopsy", can analyse histology and cytology features of a tissue which otherwise is only possible by tissue biopsy. Similar to confocal microscopy, the laser in CLE filtered by the pinhole excites the fluorescent dye through a beam splitter and objective lens. The fluorescent emission then follows similar paths into the detector. A pinhole is used to select emissions from the desired focal plane. Two categories of CLE exist, namely probe-based (pCLE) and the less common endoscopy-based endoscopy (eCLE).
{{cite journal}}
: CS1 maint: numeric names: authors list (link)