Gastrointestinal Tract (GIT) Update PDF

The Gastrointestinal Tract (1) Dr. Raja Elkwafi 1  Oral inflammatory lesions Aphthous Ulcers (Canker Sores):  It is a common, self-limiting condition (resolve spontaneously ), but can recur.  It is small (less than 5mm), painful, shallow, ul...

The Gastrointestinal Tract (1) Dr. Raja Elkwafi 1  Oral inflammatory lesions Aphthous Ulcers (Canker Sores):  It is a common, self-limiting condition (resolve spontaneously ), but can recur.  It is small (less than 5mm), painful, shallow, ulcer.  It affects the oral mucosa, soft palate, buccal and labial mucosa, floor of the mouth.  unknown cause, may be associated with celiac disease, inflammatory bowel disease, and Behçet disease, it is triggered by stress, fever. Herpes Simplex Virus Infections:  Called fever blister or cold sore  -Cause: HSV type I  -The primary infection is usually asymptomatic, the virus will persist in a dormant state within the local ganglia (e.g. trigeminal) and get reactivation by:  Oral inflammatory lesions Factors that cause reactivation of HSV: 1.Trauma 2.Fever or excessive cold 3.Exposure to ultraviolet light (sunlight) 4.Upper respiratory tract infections 5.Pregnancy 6.Menstruation 7.Immunosuppression This will lead to the formation of small vesicles which rupture and leave a shallow painful ulcer located around the mouth, lips &nasal orifices 3 Oral Candidiasis (Thrush)  Candidiasis is the most common fungal infection of the oral cavity Causative agent: Candida albicans. Gross: Adherent white curd like plaque (fibrino-suppurative exudate with matted micro- organisms) which is after scrapping will reveal an erythematous inflammatory base. Etiological factors: It is opportunistic infection, candida is present in the oral cavity in 50% of population, so it will appear if there is any decrease in immunity e.g. 1 Diabetes mellitus 2 Immunodeficiency (congenital or acquired like AIDS) 3Some drugs like: glucocorticoid therapy, chemotherapy and Immunosuppressive treatment after organ transplant, broad spectrum antibiotic (that eliminate or alter the normal bacterial flora of the mouth) 4 Debilitating diseases e.g. CA.  Proliferative and neoplastic lesions of the oral cavity Fibromas Fibromas are sub mucosal nodular fibrous tissue masses that are formed when chronic irritation results in reactive connective tissue hyperplasia Pyogenic granuloma – It is an inflammatory lesion typically found on the gingiva of children, young adults, and pregnant women (pregnancy tumour) 5 Proliferative and neoplastic lesions of the oral cavity Leukoplakia and Erythroplakia – Leukoplakia is defined by the World Health Organization as “a white patch or plaque that cannot be scraped off and cannot be characterized clinically or pathologically as any other disease” – 5% to 25% are dsyplastic and at risk for progression to squamous cell carcinoma – Until proved otherwise by means of histologic evaluation, all leukoplakias must be considered precancerous Leukoplakia 6  Proliferative and neoplastic lesions of the oral cavity Leukoplakia and Erythroplakia – Erythroplakia is a red, velvety, sometimes eroded lesion that is flat or slightly depressed relative to the surrounding mucosa – Erythroplakia is associated with a much greater risk for malignant transformation than leukoplakia – Although the etiology is multifactorial, tobacco use (cigarettes, pipes, cigars, and chewing tobacco) is the most common risk factor for leukoplakia and erythroplakia 7 erythroplakia  Proliferative and neoplastic lesions of the oral cavity On histologic examination leukoplakia and erythroplakia show a spectrum of epithelial changes: Hyperkeratosis (thick keratin layer), acanthotic mucosal epithelium (thick spinous layer due to hyperplasia), Markedly dysplastic changes sometimes merging into carcinoma in situ  Proliferative and neoplastic lesions of the oral cavity Squamous Cell Carcinoma – Approximately 95% of cancers of the oral cavity are squamous cell carcinomas, with the remainder largely consisting of adenocarcinomas of salivary glands – Pathogenesis: Squamous cancers of the oropharynx arise through two distinct pathogenic pathways One involving exposure to carcinogens: chronic alcohol and tobacco (both smoked and chewed)/(TP53 & RAS genes) The other related to infection with high risk variants of human papilloma virus (HPV)/“high-risk” subtypes, particularly HPV-16 9  Diseases of salivary glands Xerostomia – Xerostomia is defined as a dry mouth resulting from a decrease in the production of saliva Autoimmune disorder (Sjögren syndrome) Complication of radiation therapy Side effect of many common classes of medications – Complications: increased rates of dental caries/candidiasis/difficulty in swallowing and speaking Sialadenitis – It is an inflammation of the salivary glands – May be induced by trauma, viral (mumps) or bacterial infection, or autoimmune disease – The mucocele is the most common inflammatory lesion of the salivay glands results from either blockage or rupture of a salivary gland duct, with consequent leakage of saliva into the surrounding connective tissue stroma. 10 Mucocele occurs most often in toddlers, young adults, and older adults, and typically manifests as a fluctuant swelling of the lower lip that may change in size, particularly in association with meals. Mucocele  Salivary gland tumours Histopathologic classification and prevalence of the most common benign and malignant salivary gland tumours 12  Salivary gland tumours Morphological features of pleomorphic adenoma – It typically manifests as rounded, well demarcated masses – The capsule is not fully developed, and produces protrusions into the surrounding tissues – The cut surface is gray-white and typically contains myxoid and blue translucent chondroid (cartilage-like) areas – It consists of a mixture of ductal (epithelial), myoepithelial, and mesenchymal cells, which explains why they are also termed mixed tumours – Epithelial elements are arranged in ducts, acini, irregular tubules, strands, or even sheets of cells. – These elements typically are dispersed within a mesenchyme-like background of loose myxoid tissue containing islands of chondroid and, rarely, foci of bone. – Pleomorphic adenomas represent about 60% of tumors in the 13 parotid gland.  Salivary gland tumours Pleomorphic adenoma They present as slow-growing, painless, mobile discrete masses. They recur if incompletely excised 14  Salivary gland tumours Mucoepidermoid Carcinoma Morphological Features : – It can grow as large as 8 cm in diameter – It lacks well-defined capsules and often are infiltrative – The cut surface is pale gray to white and frequently demonstrates small, mucinous cysts – They occur mainly (60%–70%) in the parotids – On histologic examination, these tumours contain cords, sheets, or cysts lined by squamous, mucous, or intermediate cells – The intermediate cells is a hybrid cell type with both squamous features and mucus-filled vacuoles 15 Salivary gland tumours Mucoepidermoid carcinoma 16  Obstructive and vascular diseases of oesophagus Mechanical Obstruction – Absence, or agenesis, of the esophagus is extremely rare – Atresia, in which a thin, noncanalized cord replaces a segment of esophagus, is more common/ It occurs most frequently at or near the tracheal bifurcation and usually is associated with a fistula – Esophageal stenosis may be congenital or more commonly acquired – Stenosis due to inflammation and scarring may be caused by chronic gastroesophageal reflux, irradiation, ingestion of caustic agents 17  Obstructive and vascular diseases of oesophagus Functional Obstruction – Functional obstruction results from disruption of coordinated peristalsis after swallowing – Achalasia (Greek: does not relax): – Failure of the lower esophageal sphincter to relax in response to swallowing leading to accumulation of food in the more proximal esophagus causing its dilatation & inflammation (esophagitis) – It is characterized by three major abnormalities: 1. Incomplete relaxation of the LES in response to swallowing 2. Increased resting tone of the LES 3. A peristalsis (failure of peristalsis)  Primary achalasia is idiopathic  Secondary achalasia occurs in Chagas disease, in which Trypanosoma cruzi infection  Achalasia-like disease may be caused by diabetic autonomic neuropathy, infiltrative disorders such as malignancy, amyloidosis, or sarcoidosis.. 18  Ectopia – Ectopic tissues are common in GIT – The most frequent site of ectopic gastric mucosa is the upper third of the esophagus, where it is referred to as an inlet patch, Although the presence of such tissue generally is asymptomatic, acid released by gastric mucosa within the esophagus can result in dysphagia, esophagitis, Barrett esophagus, or, rarely, adenocarcinoma  Obstructive and vascular diseases of oesophagus Esophageal Varices – Varices are tortuous dilated veins lying primarily within the submucosa of the distal esophagus and proximal stomach – Pathogenesis: Esophageal varices are caused by portal hypertension, which is due to impaired blood flow through the portal venous system and liver Increased portal venous pressure results in the development of collateral channels – In patients with cirrhosis, alcoholic liver disease/ hepatic schistosomiasis 20 Obstructive and vascular diseases of oesophagus Esophageal Varices 21  Obstructive and vascular diseases of oesophagus Esophageal Varices – Morphology: Esophageal varices are tortuous dilated veins within the mucosa and submucosa of the distal esophagus and proximal stomach. Variceal rupture can result in hemorrhage into the lumen or the esophageal wall and may be associated with mucosal ‘ulceration and necrosis. – Clinical Features: Varices often are asymptomatic, but their rupture can lead to massive hematemesis and death. Variceal rupture therefore constitutes a medical emergency 22  Esophagitis The main types of the esophagitis: Chemical and Infectious Esophagitis Reflux Esophagitis Eosinophilic Esophagitis Esophageal Lacerations: the most common esophageal lacerations are Mallory-Weiss tears, which are often induced by severe retching or vomiting. 23  Esophagitis Reflux Esophagitis Reflux of gastric contents into the lower esophagus is the most frequent cause of esophagitis and the most common outpatient GI diagnosis in the US The associated clinical condition, termed gastroesophageal reflux disease (GERD) Pathogenesis – Reflux of gastric juices is central to the development of mucosal injury in GERD 24  Esophagitis Pathogenesis Conditions that decrease lower esophageal sphincter tone or increase abdominal pressure contribute to GERD and include:  Alcohol and tobacco use, obesity, central nervous system depressants, pregnancy, hiatal hernia, delayed gastric emptying, and increased gastric volume  In many cases, no definitive cause is identified  The most frequently reported symptoms are heartburn, dysphagia, regurgitation of sour-tasting gastric contents  Rarely, chronic GERD is punctuated by attacks of severe chest pain that may be mistaken for heart disease 25  Barrett Esophagus Barrett esophagus is a complication of chronic GERD that is characterized by intestinal metaplasia within the esophageal squamous mucosa It is estimated to occur in as many as 10% of individuals with symptomatic GERD White males/between 40 and 60 years of age The greatest concern in Barrett esophagus is that it confers an increased risk for development of esophageal adenocarcinoma 26  Barrett Esophagus Morphology: Barrett esophagus is recognized endoscopically Tongues or patches of red, velvety metaplastic mucosa extending upward from the gastroesophageal junction Histologically: gastric or intestinal metaplasia/the presence of goblet cells Dysplasia is classified as low-grade or high-grade on the basis of morphologic criteria 27 Esophageal tumours 28  Esophageal tumours Two morphologic variants account for a majority of esophageal cancers: adenocarcinoma and squamous cell carcinoma Squamous Cell Carcinoma Typically occurs in adults older than 45 years of age and affects males four times more frequently than females The regions with highest incidence are Iran, central China, Hong Kong, Brazil, and South Africa/western Kenya has been linked to consumption of a traditional fermented milk, termed mursik, which contains the carcinogen acetaldehyde Risk factors include: alcohol and tobacco use, poverty, caustic esophageal injury, achalasia, Plummer-Vinson syndrome, diets that are deficient in fruits or vegetables, and frequent consumption of very hot beverages and previous radiation to the mediastinum 29  Esophageal tumours Squamous Cell Carcinoma Morphology – Half of squamous cell carcinomas occur in the middle third of the esophagus – Squamous cell carcinoma begins as an in situ lesion in the form of squamous dysplasia – Early lesions appear as small, gray-white plaque like thickenings – It can grow into tumour masses that may be polypoid and protrude into and obstruct the lumen or into ulcerated or diffusely infiltrative lesions/cause thickening, rigidity, and luminal narrowing 30  Esophageal tumours Squamous Cell Carcinoma Morphology: Histologically: Most squamous cell carcinomas are moderately to well differentiated Clinical Features: dysphagia, odynophagia (pain on swallowing), and obstruction/weight loss/symptoms caused by aspiration of food via a tracheoesophageal fistula. 31  Esophageal tumours Adenocarcinoma Esophageal adenocarcinoma typically arises in a background of Barrett esophagus and long-standing GERD Risk for development of adenocarcinoma is greater in patients with documented dysplasia and in those who use tobacco, are obese, or who have had previous radiation therapy Rates being highest in Western countries, including the United States, the United Kingdom, Canada, Australia, and the Netherlands 32  Esophageal tumours Adenocarcinoma Morphology – Esophageal adenocarcinoma usually occurs in the distal third of the esophagus and may invade the adjacent gastric cardia – Early lesions may appear as flat or raised patches/later tumours may form large exophytic masses, infiltrate diffusely, or ulcerate and invade deeply – Microscopically: Barrett esophagus frequently is present adjacent to the tumour/tumours typically produce mucin and form glands Clinical Features: pain or difficulty in swallowing, progressive weight loss, chest pain, or vomiting 33  References Robbins basic pathology, 10th edition, 2018 Robbins and Cotran Pathologic Basis of Disease. Copyright © 2020 by Saunders, an imprint of Elsevier Inc. Textbook of Pathology, Seventh Edition. Copyright © 2015, Harsh Mohan Thank you