Download - Introduction to the GIT system
Introduction to the GIT system
Pathology lecture: 1
Dr. Dua Abuquteish, MBBS
▪
MBBS: J.U.S.T/ Jordan
▪
Pathology Residency: K.A.U.H / Jordan
▪Gastrointestinal / liver pathology clinical fellowship: University of Toronto/ Canada
Notes about the GIT system
Coordinator: Dr. Dua Abuquteish
Contact email: [email protected]
My room: 1020
The GIT system has 61 lectures
15 are pathology lectures
Pathology labs will include the images from the lectures (TBD).
Two theory exams (40% each) and one practical 20%, all the exams will be at the end of the system
For more details regarding the system, please refer to your syllabus
Questions
For questions and inquiries:
▪Ask direct in the lecture
▪Or please email me
Please specify in the email subject (Question; lecture # or lecture title)
▪Do NOT chat the question on Microsoft teams
▪Please feel free to come to my office #1020
From where to study pathology and what’s included in the exam?
Slides
Book (Robbins Basic
Pathology, 10th edition)
I did NOT give consent for video recording Thus, you will be subject to legal liability
Let’s start!
What does the GIT system include?
How does the digestive system work?
The most common symptoms of gastrointestinal diseases
How are the patients with GIT symptoms diagnosed?
History taking
Clinical inspection
Lab test (CBC, LFT, Fecal occult blood in stool; FOBT)
Imaging (abdominal ultrasound, MRCP, ERCP, barium enema)
Non-surgical procedures: upper and lower endoscopy (colonoscopy)
Surgical procedures (laparoscopy or laparotomy)
The fecal occult blood test (FOBT) is a lab test used to check stool samples for hidden (occult) blood
Barium enema
A barium enema is a radiographic (X-ray) examination of the lower gastrointestinal (GI) tract.
The large intestine, including the rectum, is made visible on X-ray film by filling the colon with a liquid suspension called barium sulfate (barium).
Upper endoscopy: Is a nonsurgical procedure used to examine a person's digestive tract. Using an endoscope, a flexible tube with a light and camera attached to it, your doctor can view pictures of your digestive tract on a color TV monitor.
Upper endoscopy
Tissue samples (biopsies) can be taken during endoscopy.
Colonoscopy (lower endoscopy): Is a long, flexible tube (colonoscope) that is inserted into the rectum. A tiny video camera at the tip of the tube allows the doctor to view the inside of the entire colon.
Colonoscopy
Tissue samples (biopsies) can be taken during colonoscopy
Laparoscopy
Laparotomy(open surgery)
Is a surgical incision (cut) into the abdominal cavity
What is the role of pathology in diagnosing patients?
The pathologist receives biopsies and specimensthat are obtained from surgical and non-surgical procedures:
Non-surgical procedures: Upper and lower endoscopy (colonoscopy)
Surgical procedures (laparoscopy or laparotomy)
Specimens go to pathology lab
Steps in Biopsy processing
Grossing
Processing and Hematoxylin and eosin stainingH&E
Reporting
Example of a final pathology report
Example of a final pathology report
Immunohistochemistry
Sometimes stains, other than H&E, are used to confirm the
diagnosis.
Immunohistochemistry (IHC) is a technique that uses antibodies conjugated to enzymes that catalyze reactions to form detectable compounds to visualize and localize specific antigens in a tissue sample.
H&E: CMV inclusions
Immunohistochemistry: CMV inclusions
ORAL CAVITY
Diseases affecting teeth their support structures, oral mucosa, salivary glands, and jaws.
DISEASES OF TEETH AND SUPPORTING STRUCTURES
Dental Carries
Gingivitis
Periodontitis
Dental Carries
Most common cause of tooth loss in individuals younger than 35 years of age.
Caries results from focal demineralization of tooth structure (enamel and dentin) caused by acids generated during the fermentation of sugars by bacteria.
Gingivitis
Gingivitis is inflammation involving the squamous mucosa and associated soft tissues that surrounds the teeth.
It is associated with buildup of dental plaque and calculus
Associated with poor oral hygiene
Chronic gingivitis shows gingival erythema, edema, and bleeding.
Gingivitis is reversible, primarily by regular brushing and flossing of teeth
Periodontitis
Periodontitis is a chronic inflammatory condition
that can lead to the destruction of the supporting
structures of the teeth.
With progression, periodontitis may result in
destruction of periodontal ligament and alveolar
bone and eventual tooth loss.
It is associated with poor oral hygiene and altered
oral microbiota.
ORAL INFLAMMATORY
LESIONS
Aphthous Ulcers (Canker Sores)
Herpes Simplex Virus Infections
Oral Candidiasis (Thrush)
Aphthous Ulcers (Canker Sores)
Up to 40% of population (very common!)
More frequent in the first 2 decades of life
Extremely painful, and often recur
Unknown etiology (?viruses, hypersensitivity)
Triggered by stress, fever, menstruation, pregnancy, certain foods; may be familial
May be associated with inflammatory bowel disease & Behcet syndrome
Self limiting in a few weeks, but can recur
Aphthous Ulcers (Canker Sores)
Solitary or multiple; typically, they are shallow, with a hyperemic base covered by a thin exudate and rimmed by a narrow zone of erythema, usually <1 cm, may coalesce
Herpes Simplex Virus
(HSV) Infections
“Herpetic stomatitis”
Most orofacial herpetic infections are HSV-1, with the
remainder being HSV-2 (genital herpes)
Person to person transmission
Patients presents with vesicles (cold sores, fever
blisters) that rupture and heal, without scarring, and
often leave latent virus in nerve ganglia.
Primary infection is self limited. Reactivation occurs
when there is a compromise in host resistance.
Herpes Simplex Virus (HSV) Infections“Herpetic stomatitis”
Primary infections typically in children (2 to
4 years) and are often asymptomatic.
However, 10% to 20% manifests as acute
herpetic gingivostomatitis (abrupt onset of
vesicles and ulcerations throughout the oral cavity).
Acute herpetic gingivostomatitis
After primary infection virus will persist in ganglia in dormant state
In adulthood, the virus can be reactivated, resulting in a so-called “cold sore” or “recurrent herpetic stomatitis”.
Reactivation: fever, sun or cold exposure, URTI, ..
Most common locations involved: the lips (herpes labialis), nasal orifices, buccal mucosa, gingiva, and hard palate.
Self limiting in a few weeks, but can recur
They can persist in immunocompromised patients, who may require systemic anti-viral therapy.
Herpes Simplex Virus
(HSV) Infections
“Herpetic stomatitis”
Herpes Simplex Virus (HSV) Infections
“Herpetic stomatitis”
The infected cells become ballooned and have large eosinophilic intranuclear inclusions.
Adjacent cells commonly fuse to form large multinucleated polykaryons.
Oral Candidiasis (Thrush)
Candidiasis is the most common fungal infection of the oral cavity.
Candida albicans is a normal component of the oral flora.
However, can produce disease when the oral microbiota is altered
(e.g., after antibiotic use) and in immunosuppression
Invasive disease may occur in severe immunosuppressed
individuals.
Three major clinical forms of oral candidiasis are:
1. Pseudomembranous (most common and is known as thrush)
2. Erythematous
3. Hyperplastic
Oral Candidiasis (Thrush)
❑ Superficial, curdlike, gray to white inflammatory membrane composed of matted organisms.
❑This layer can be readily scraped off to reveal an underlying erythematous base.
Densely matted pseudohyphae and budding spores
PROLIFERATIVE AND
NEOPLASTIC LESIONS OF
THEORAL CAVITY
▪Fibrous Proliferative Lesions
(Fibromas and pyogenic granuloma)
▪Leukoplakia and Erythroplakia
▪Squamous Cell Carcinoma
Fibromas
Submucosal nodular fibrous tissue masses that are formed when chronic irritation results in reactive connective tissue hyperplasia.
They occur most often on the buccal mucosa along the bite line.
Treatment: complete surgical excision and removal of the source of irritation.
Pyogenic granuloma
An inflammatory lesion typically found on the gingiva of children, young adults, and pregnant women (pregnancy tumor).
Complete surgical excision is definitive treatment.
These lesions are richly vascular and typically ulcerated, which gives them a red to purple color. In some cases, growth can be rapid and raise fear of a malignant neoplasm.
Histologically: Proliferation of immature vessels like that seen in granulation tissue
Leukoplakia and
Erythroplakia
Leukoplakia: is a white patch or plaque that cannot be
scraped off and cannot be characterized clinically or
pathologically as any other disease.
White patches caused by obvious irritation or entities such
as candidiasis are NOT considered leukoplakia.
5% to 25% are dysplastic and at risk for progression to
squamous cell carcinoma.
Thus, until proved otherwise, all leukoplakias must be
considered precancerous.
Leukoplakia
Erythroplakia
Erythroplakia, less common entity, 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 (up to 50%).
Leukoplakia and erythroplakia, the usual age (40 - 70 years)
Tobacco use (cigarettes, pipes, cigars, and chewing tobacco)
is the most common risk factor for leukoplakia and
erythroplakia.
Erythroplakia
Red, velvety, sometimes eroded lesion that is flat or slightly depressed
Leukoplakia
On histologic examination
leukoplakia and erythroplakia
show a spectrum of epithelial changes ranging from hyperkeratosis, acanthothosis, to markedly dysplasia and sometimes merging into carcinoma in situ
Normal squamous
mucosa
Note the sharp demarcation between normal and leukoplakia. Leukoplakia shows acanthosis and hyperkeratosis. No epithelial atypia.
Leukoplakia
Example of erythroplakia with squamous epithelial atypia (dysplasia)
Squamous Cell Carcinoma
SCC
95% of the oral cavity cancers are SCC
Most common locations are: ventral surface of
the tongue, floor of the mouth, lower lip, soft
palate, and gingiva
Survival rate < 50% for the past 50 years
(diagnosed at advanced stage).
Squamous Cell Carcinoma
SCC
Pathogenesis
SCC of oropharynx arise through two distinct pathogenic pathways:
1. Exposure to carcinogens (chronic alcohol and tobacco, betel quid and paan), mutations frequently involve TP53 and genes that regulate cell proliferation, such as RAS
2. Infection with high-risk variants of human papilloma virus (HPV).
HPV-related tumors tend to occur in the tonsillar crypts
or the base of the tongue and harbor oncogenic “high-
risk” subtypes, particularly HPV-16.
HPV-related tumors have fewer mutations; often
overexpress p16
The prognosis for patients with HPV-positive tumors is
better than for those with HPV-negative tumors.
Squamous Cell Carcinoma
SCC
Squamous Cell Carcinoma
SCC
➢Marked atypical tumor cells with invasion and islands that show formation of keratin pearls
➢May be superimposed on a background of leukoplakia or erythroplakia
keratin pearls
Squamous Cell Carcinoma
SCC
Typically, oral squamous cell carcinoma infiltrates locally before it metastasizes.
The cervical lymph nodes are the most common sites of regional metastasis; frequent sites of distant metastases include the mediastinal lymph nodes, lungs, and liver.
Diseases of Salivary glands
Diseases of Salivary glands
Three major salivary glands:
❑Parotid
❑Submandibular
❑Sublingual
—as well as innumerable minor salivary glands distributed throughout the oral mucosa.
Diseases of salivary glands include:
Inflammation
Neoplasms (Benign and Malignant)
Diseases of Salivary glands
Xerostomia
Xerostomia is defined as a dry mouth resulting from a decrease in the production of saliva.
Causes:
Part of autoimmune disorder Sjögren syndrome; also accompanied by dry eyes.
Complication of radiation therapy.
Medications such as: anti-cholinergic, anti-depressant/ anti-psychotic, diuretic, anti-hypertensive, sedative, muscle relaxant, analgesic, and anti-histaminic agents.
Diseases of Salivary glands
Sjogren's syndrome An autoimmune disease, in which the immune system attacks the exocrine glands (glands that make tears and saliva). This causes a dry mouth (Xerostomia) and dry eyes (Xerophthalmia)
Xerostomia
The oral cavity may reveal only dry mucosa and/or atrophy of the papillae of the tongue, with fissuring and ulcerations
Diseases of Salivary glands
Xerostomia
Complications include increased rates of dental caries and candidiasis, as well as difficulty in swallowing and speaking.
Diseases of Salivary glands
Sialadenitis (inflammation of the salivary glands)
May be induced by trauma, viral or bacterial infection,
or autoimmune disease.
Viral sialadenitis: the most common form is mumps
Mumps predominantly involves the parotids, and
causes enlargement of salivary glands.
Mumps produces interstitial inflammation marked by a
mononuclear inflammatory infiltrate.
Mumps in children is most often a self-limited benign
condition, in adults it can cause pancreatitis or orchitis.
Diseases of Salivary glands
Diseases of Salivary glands
Bacterial sialadenitis
The most frequent pathogens are Staphylococcus aureus
and Streptococcus viridans
Bacterial sialadenitis most often involves the
submandibular glands.
Dehydration and decreased secretory function can
predispose to bacterial invasion.
Autoimmune sialadenitis (Sjögren syndrome).
Diseases of Salivary glands
Mucocele
Most common inflammatory lesion of the salivary glands
Results from blockage/rupture of a salivary gland duct, with consequent leakage of saliva into the surrounding connective tissue stroma.
Presents with fluctuant swelling of the lower lip that may change in size, particularly in association with meals
Rx: complete excision.
Diseases of Salivary glands
Mucocele
Cyst-like space lined by granulation tissue or fibrous connective tissue that is filled with mucin and inflammatory cells, particularly macrophages
Diseases of Salivary glands
Salivary gland neoplasms
2% of all human tumors
65% to 80% arise within the parotid gland, 10% in the submandibular gland, and the remainder in the minor salivary glands, including the sublingual glands
Clinically, parotid gland neoplasms produce swelling in front of and below the ear.
Benign tumors are slow growing (months to years)
Malignant more often come to attention promptly, probably because of their more rapid growth.
Diseases of Salivary glands
The likelihood that a salivary gland tumor is
malignant is inversely proportional, roughly, to the
size of the gland:
15% to 30% of tumors in the parotid glands are
malignant
In contrast, approximately 40% of submandibular,
50% of minor salivary gland,
70% to 90% of sublingual tumors are malignant.
Diseases of Salivary glands
➢Most common benignsalivary gland tumor is pleomorphic adenoma
➢Most common malignant salivary gland tumor is Mucoepidermoid carcinoma
Diseases of Salivary glands
Pleomorphic Adenoma (mixed tumor)
Benign tumors
Consist of a mixture of ductal (epithelial) and
myoepithelial cells (mesenchymal)
PA represent 60% of tumors in the parotid, are less
common in the submandibular glands and others
Slow-growing, painless, mobile discrete masses
They recur if incompletely excised
Diseases of Salivary glands
(Pleomorphic Adenoma)
Pleomorphic adenomas typically manifest as rounded, well-demarcated masses rarely exceeding 6 cm in the greatest dimension
Diseases of Salivary glands
They are encapsulated,
The cut surface is gray-white and typically contains myxoid and blue translucent chondroid (cartilage-like) areas.
Diseases of Salivary glands
(Pleomorphic Adenoma)
Diseases of Salivary glands
(Pleomorphic Adenoma)
Diseases of Salivary glands
Pleomorphic Adenoma (mixed tumor)
Carcinoma arising in a pleomorphic adenoma is referred
to variously as a “carcinoma ex pleomorphic adenoma”
or “malignant mixed tumor”.
The incidence of malignant transformation increases with
time (2% if less than 5 years) and (10% if present more
than 15 years).
The cancer usually takes the form of an adenocarcinoma.
Diseases of Salivary glands
Mucoepidermoid Carcinoma (MEC)
Mucoepidermoid Carcinoma (MEC)
Malignant neoplasm of variable biologic aggressiveness
MEC are composed of variable mixtures of squamous cells, mucus-
secreting cells, and intermediate cells.
MEC is the most common form of primary malignant tumor of the
salivary glands (15% of all salivary gland tumors)
They occur mainly (60%–70%) in the parotids
Clinical course and prognosis depend on histologic grade
Recur in 25% to 30% of cases, and about 30% metastasize to distant
sites.
Diseases of Salivary glands
Mucoepidermoid Carcinoma (MEC)
Gross pathology:
Well-circumscribed to partially encapsulated to unencapsulated
Mucoepidermoid Carcinoma (MEC)
Solid areas of the tumor are formed by different proportions of epidermoid (squamous) cells (red arrow), mucus cells (green arrow) and intermediate cells (yellow arrow)
Diseases of Salivary glands
Mucoepidermoid Carcinoma (MEC)
Diseases of Salivary glands
Mucoepidermoid Carcinoma (MEC)