[07.22] Patho Lab (GI-Nutri) Gastrointestinal Pathologies V2.pdf

Cholethiasis

What is the medical term for the presence of gallstones within the gallbladder?

Cholesterol stones and Pigment stones

What are the two primary types of gallstones classified by their composition?

Supersaturation of bile and cholesterol with gallbladder hypomotility

What is the etiopathogenesis behind the formation of cholesterol gallstones?

Diet, obesity, and rapid weight loss

What are the three specific risk factors listed for cholesterol stones?

Rounded and granular

What is the gross surface description of a cholesterol gallstone?

Bilirubin and calcium salts

What chemical components make up pigment stones?

Brown and Black

What are the two colors pigment stones can present as?

Asian populations

In which specific population are pigment stones noted to be common?

Smooth, multifaceted, speculated, or molded

How is the gross surface of a pigment stone described?

Cholesterolosis

What condition occurs when cholesterol deposits into the lamina propria of the gallbladder?

Yellow excrescences or flecks (Strawberry gallbladder)

Grossly, what does the accumulation of cholesterol-laden macrophages in the gallbladder mucosa look like?

Foam cells

What is the term for cholesterol-laden macrophages seen microscopically in cholesterolosis?

Adenocarcinoma

What is the most common malignancy found in the stomach?

Infiltrative and Diffuse

What are the two morphological types of gastric adenocarcinoma?

Rough and exophytic masses

What gross shape does infiltrative gastric adenocarcinoma typically form?

Heaped up borders and central ulceration

What are the gross characteristics of the ulcers found in gastric adenocarcinoma?

Rugae

What are the normal folds of the stomach lining called?

Intussusception

What occurs when one part of the intestines telescopes into the immediately distal segment?

Children

In which age group is intussusception most commonly found?

Peristalsis

Once trapped, what physiological process propels the invaginated segment and pulls the mesentery along?

Intussusceptum

What is the term for the "entering" segment in intussusception?

Intussuscipiens

What is the term for the "receiving" segment in intussusception?

Infarction (Ischemic colitis)

What is the primary vascular complication of intussusception caused by the impingement of blood vessels?

Acute or sharp pain

How does intussusception typically present clinically?

Familial Adenomatous Polyposis (FAP)

Which condition is characterized grossly by a mucosal surface covered in a "carpet of polyps"?

Presence of more than 100 polyps

Grossly, what number of polyps is generally required for a diagnosis of FAP via endoscopy?

Tubular adenoma

Which type of adenomatous polyp is described as being rounded in shape?

Villous adenoma

Which type of adenomatous polyp is characterized by long, finger-like projections?

Villous adenoma

Which type of colonic adenoma carries the highest risk of developing into an adenocarcinoma?

Tubulovillous adenoma

What is the term for an adenoma that contains a combination of tubular and villous growth patterns?

Diverticulosis

What is the term for an outpouching of the mucosa through naturally weak points in the GI tract wall?

Sigmoid colon

In which segment of the gastrointestinal tract is diverticulosis most commonly found?

Constant high pressure

What physiological factor causes weak points in the colon to develop into outpouchings?

Diverticulitis

What is the term for diverticulosis when inflammation is present?

Neutrophilic infiltrates in the muscularis propria

What is the specific histological requirement for a definitive diagnosis of acute appendicitis?

Obstruction of the appendiceal lumen

What is the primary initiating event in the pathogenesis of acute appendicitis?

Stool, fecalith, gallstones, tumors, or a mass of worms

What are five potential causes of appendiceal lumen obstruction?

Increase in intraluminal pressure

In appendicitis, what does the continuous secretion of fluids and mucus against an obstruction lead to?

Ischemia and proliferation of bacteria

What two factors promote the formation of pus within the appendix?

Occlusion of venous outflow

What vascular event leads to the final loss of epithelial integrity and bacterial invasion in appendicitis?

Mesenteric lymphadenitis

Which condition, often secondary to Yersinia infection, is a common clinical mimic of appendicitis?

Mittelschmerz

What is the term for pelvic pain due to minor bleeding during ovulation that can mimic appendicitis?

Acute salpingitis, Ectopic pregnancy, PID, and Meckel’s diverticulitis

List four other clinical mimics of acute appendicitis mentioned in the sources.

Periappendiceal abscess or diffuse peritonitis

What are the two major results of appendiceal perforation?

Inflammation causes intestinal muscle to stop working

How does acute appendicitis lead to intestinal obstruction?

Inflammatory Bowel Disease (IBD)

What is the chronic condition resulting from inappropriate mucosal immune responses against intestinal microbiota in genetically predisposed hosts?

Crohn Disease and Ulcerative Colitis

IBD is comprised of which two main disorders?

Crohn Disease

Which IBD disorder is characterized by "skip lesions"?

Ulcerative Colitis

Which IBD disorder involves only the colon and rectum in a diffuse, continuous pattern?

Non-caseating granulomas

What histological feature is considered a "hallmark" of Crohn Disease but is absent in Ulcerative Colitis?

Transmural

What is the typical depth of inflammation in Crohn Disease?

Limited to mucosa and submucosa

What is the typical depth of inflammation in Ulcerative Colitis?

Regional enteritis

What is an alternative name for Crohn Disease due to its frequent involvement of the ileum?

Terminal ileum, ileocecal valve, and cecum

What are the three most common sites involved in Crohn Disease?

Strictures

Which macroscopic feature is common in Crohn disease but rare in ulcerative colitis (except in long-standing cases)?

Paneth cell metaplasia

What type of cell metaplasia can occur in the left colon in Crohn Disease?

Migratory polyarthritis, sacroiliitis, ankylosing spondylitis, uveitis, and skin lesions

List the five extraintestinal manifestations shared by Crohn and Ulcerative Colitis.

Toxic megacolon

Which clinical complication is associated with Ulcerative Colitis but not Crohn Disease according to the comparison table?

Well-differentiated adenocarcinoma

In colorectal carcinoma, what classification is given to tumor cells with hyperchromatic nuclei that form irregular glands containing necrotic debris?

Necrotic debris ("Dirty necrosis")

What is the "pink fluffy material" often found within the glands of a colorectal adenocarcinoma?

Poorly differentiated

A colorectal adenocarcinoma that forms few or no glands and is composed of infiltrating nests of cells is classified as what?

Signet-ring cells and extracellular mucin pools

What are the two main features of a mucinous adenocarcinoma of the colon?

Adenomas

Colorectal carcinoma typically originates from which precursor lesions?

Direct growth through the bowel wall and invasion of lymphatic/venous channels

How does colorectal cancer spread?

Cribriform shape

What is the term for large, irregularly shaped gland structures with numerous "punched out" holes resembling a plate in the nose?

Decreased goblet cells

What happens to the number of goblet cells in rectosigmoid adenocarcinoma?

Iron deficiency anemia, fatigue, and weakness

What are the three main signs and symptoms of Right-sided colonic cancer?

Low stool caliber, LLQ pain, and blood-streaked stool

What are the three main signs and symptoms of Left-sided colonic cancer?

Polypoid exophytic masses

What is the typical morphology of Right-sided colonic tumors?

Annular "napkin ring" lesions producing luminal narrowing

What is the typical morphology of Left-sided colonic tumors?

Left-sided (Distal)

Which side of colonic cancer is more likely to cause obstruction?

Desmoplastic response

What is the term for the strong stromal reaction elicited by the invasive component of colonic cancer that gives it a firm consistency?

50 years or older

At what age does the risk for colorectal cancer significantly increase according to genetic/physiologic factors?

Lynch Syndrome

Besides FAP, what is the other major family history syndrome listed as a risk factor for colorectal cancer?

Sedentary lifestyle, obesity, smoking, alcoholism, and a diet low in fiber/high in fat

List five lifestyle risk factors for colorectal cancer.

Epithelial dysplasia

What is the defining microscopic characteristic of colorectal adenomas?

Pedunculated

What is the term for a polyp that is attached to the mucosa by a stalk?

Sessile

What is the term for a polyp that is flat and attached directly to the mucosa?

Velvet or a raspberry

What is the texture of an adenoma's surface compared to in the sources?

Nuclear hyperchromasia, elongation, and stratification

What are the three histological hallmarks of epithelial dysplasia?

Eosinophilic cytoplasm

What color does the cytoplasm of cells in an adenoma typically appear under the microscope?

APC/WNT pathway (APC gene)

Which molecular pathway and gene are associated with FAP and 70-80% of sporadic colon cancers?

DNA mismatch repair (MSH2, MLH1)

Hereditary non-polyposis colorectal cancer (Lynch) is caused by defects in which process?

Hypermethylation (MLH1, BRAF)

What molecular defect is associated with 5-10% of sporadic colon cancers located on the right side?

Diffuse type

Which type of gastric adenocarcinoma is characterized by an infiltrative growth pattern and the loss of E-cadherin?

CDH1

Loss-of-function mutations in which tumor suppressor gene are found in 50% of sporadic diffuse gastric tumors?

Loss of E-cadherin (discohesive cells)

Why do diffuse gastric cancers permeate the wall as small clusters and individual cells rather than forming glands?

Signet-ring cells

Which cells are recognized by large cytoplasmic mucin vacuoles and peripherally displaced, crescent-shaped nuclei?

Increased Wnt signaling (APC or β-catenin mutations)

Intestinal-type gastric adenocarcinoma is strongly associated with mutations in which pathway?

Depth of invasion and extent of nodal/distant metastases

What are the two most powerful prognostic indicators for gastric cancer?

Surgery

What is the preferred treatment approach for gastric cancer if the tumor is localized?

Less than 30%

What is the overall 5-year survival rate for gastric cancer in the United States?

Gastrointestinal Stromal Tumor (GIST)

What is the most common mesenchymal tumor of the abdomen?

Interstitial cells of Cajal (pacemaker cells)

From which specific cells do GISTs arise?

Spindle cells arranged in randomly oriented fascicles

What are the histologic characteristics of a GIST?

KIT (receptor tyrosine kinase)

Approximately 75% of GISTs have oncogenic mutations in which gene?

PDGFRA

8% of GISTs have mutations in which gene, often detectable in smaller lesions?

CD117

What is the primary immunohistochemical diagnostic marker for GIST?

Spindle cell type and Epithelioid type

What are the two histological types of GIST mentioned?

Epithelioid type

Which type of GIST is noted to be resistant to medication?