SM_162b: Pathology of Colonic Disorders

Question 1

Colon is the part of the mucosa that extends from the ____ to ____

Answer 1

Colon is the part of the mucosa that extends from the cecum to rectum

Question 2

Four layers of colon are ____, ____, ____, and ____

Answer 2

Four layers of colon are the mucosa, submucosa, muscularis propria, and adventitia / serosa

Question 3

Describe staging carcinomas based on histology of colon

Answer 3

Staging carcinomas based on histology of colon

• Mucosa: Tis (in situ)
• Submucosa: T1
• Muscularis propria: T2
• Serosa: T3

Question 4

Colonic mucosa consists of ____, ____, and ____ and functions to ____ and ____

Answer 4

Colonic mucosa consists of epithelium, lamina propria, and muscularis mucosae and functions to absorb water and allow passage of stool protection

• Epithelium: absorptive cells, goblet cells, Paneth cells (only in right colon), endocrine cells
• Lamina propria: plasma cells, eosinophils, lymphocytes
• Muscularis mucosae: thin smooth layer created by gentle agitation

Question 5

These are ____ and ____

Answer 5

These are endocrine cells and Paneth cells

Question 6

Colonic submucosa consists of ____ and ____

Answer 6

Colonic submucosa consists of loose connective tissue and ganglion cells (Meissner’s plexus)

• Loose connective tissue: fibroblasts, lymphatics, blood vessels

Question 7

____ is the main layer of the GI tract and creates peristalsis

Answer 7

Muscularis propria is the main layer of the GI tract and creates peristalsis

• Inner circular smooth muscle layer
• Outer longitudinal smooth muscle layer
• Ganglion cells (Auerbach’s plexus)

Question 8

Colitis is inflammation of the colon and presents with ____, ____, ____, ____, and ____

Answer 8

Colitis is inflammation of the colon and presents with abdominal pain, diarrhea, urgency, hemorrhage, and incontinence

Question 9

Infectious colitis is most commonly ____ and involves ____ and ____

Answer 9

Infectious colitis is most commonly active inflammation and most commonly involves cryptitis and crypt abscesses

• Cryptitis: neutrophils in the epithelium
• Crypt abscesses: neutrophils in the crypt lumina
• Pattern of inflammation depends the causative agent

Question 10

Cryptitis is ____

Answer 10

Cryptitis is neutrophils in the epithelium

Question 11

Crypt abscesses are ____

Answer 11

Crypt abscesses are neutrophils in the crypt lumina

Question 12

Pseudomembranous colitis involves a pseudomembrane composed of ____, ____, and ____

Answer 12

Pseudomembranous colitis involves a pseudomembrane composed of necrotic epithelial cells, acute inflammatory cells, and fibrinous material

• Causes: Clostridioides difficile, ischemic colitis, IBD

Question 13

Describe Clostridium difficile membranous colitis pathophysiology

Answer 13

Clostridium difficile membranous colitis pathophysiology

1. Administration of antibiotic
2. Overgrowth of C. difficile
3. Production of toxins
4. Epithelial / endothelial damage and inflammation

Presents with diarrhea, abdominal pain, nausea / vomiting, fever

Question 14

Clostridium difficile pseudomembranous colitis is diagnosed via ____

Answer 14

Clostridium difficile pseudomembranous colitis is diagnosed via testing for C. difficile toxin in the stool

(endoscopy also used)

Question 15

Discrete, raised creamy yellow plaques of 1-5 mm on the colon indicates ___

Answer 15

Discrete, raised creamy yellow plaques of 1-5 mm on the colon indicates pseudomembranous colitis

(C. difficile)

Question 16

This is a ____ that occurs in ____

Answer 16

This is a pseudomembrane that occurs in pseudomembranous colitis

Question 17

Microscopic colitis is ____ with two entities: ____ and ____

Answer 17

Microscopic colitis is chronic non-bloody diarrhea with two entities: lymphocytic colitis and collagenous colitis

• Radiologic and endoscopic studies are normal
• Pathology can identify the process

Question 18

IBD is ____ that consists of ____ and ____ and presents as ____

Answer 18

IBD is chronic relapsing inflammation of all or portions of the GI tract that consists of Crohn’s Disease and Ulcerative Colitis and presents as subtle abdominal pain to bloody diarrhea

Question 19

Ulcerative colitis is primarily an ____ and begins in the ____ and progresses ____

Answer 19

Ulcerative colitis is primarily an inflammatory condition of the mucosa and begins in the rectum and progresses proximally

(may involve the entire colon)

Question 20

Ulcerative colitis involves clinical features of ____, ____, and ____

Answer 20

Ulcerative colitis involves clinical features of sudden bloody diarrhea, vague abdominal pain, and acute toxic megacolon

• Acute toxic megacolon: pancolitis -> dilatation -> no peristalsis -> rapid deterioration

Question 21

Crohn’s disease is ____, that occurs most commonly in the ____, and involves ____

Answer 21

Crohn’s disease is chronic discontinuous inflammation, that occurs most commonly in the terminal ileum and / or colon, and involves all layers of the GI tract (transmural inflammation)

Question 22

Crohn’s disease clinical features are ____, ____, ____, and ____

Answer 22

Crohn’s disease clinical features are diarrhea (chronic, nocturnal, occassionally bloody), crampy abdominal pain, fever / malnutrition / fatigue / anemia, weight loss

Question 23

Ulcerative colitis involves inflammation of ____, while Crohn’s Disease involves ____ inflammation

Answer 23

Ulcerative colitis involves inflammation of mucosa, while Crohn’s Disease involves transmural inflammation

Question 24

Ulcerative colitis histologic findings include ____, ____, and ____

Answer 24

Ulcerative colitis histologic findings include chronic inflammation, active inflammation, and limited to mucosa

• Chronic inflammation: too many lymphocytes and plasma cells in lamina propria, distorted crypt architecture
• Active inflammation: cryptitis (neutrophils in epithelium) and crypt abscess (neutrophils in the lumen of the crypt)

Question 25

Crohn's disease histologic findings include \_\_\_\_, \_\_\_\_, \_\_\_\_, and \_\_\_\_

Answer 25

Crohn's disease histologic findings include chronic inflammation, active inflammation, transmural inflammation, and noncaseating granulomas * Chronic inflammation: too many lymphocytes and plasma cells in lamina propria, distorted crypt architecture * Active inflammation (acute): cryptitis (neutrophils in epithelium)

Question 26

\_\_\_\_ has gross pathology of heal stricture, serpiginous ulcers, and cobble stone due to patchy involvement

Answer 26

Crohn's Disease has gross pathology of heal stricture, serpiginous ulcers, and cobble stone due to patchy involvement

Question 27

Describe macroscopic differences between ulcerative colitis and Crohn's Disease

Answer 27

Macroscopic differences between ulcerative colitis and Crohn's Disease * Crohn's Disease: discontinuous, terminal ileum involved * Ulcerative colitis: continuous, rectum always involved

Question 28

Describe microscopic differences between ulcerative colitis and Crohn's Disease

Answer 28

Microscopic differences between ulcerative colitis and Crohn's Disease * Ulcerative colitis: mucosal inflammation, crypt abscess common * Crohn's disease: transmural inflammation, granulomas

Question 29

\_\_\_ is a common systemic complication of ulcerative colitis

Answer 29

Primary sclerosing colangitis is a common systemic complication of ulcerative colitis * Increased risk of biliary cancer * Also toxic megacolon, hemorrhage, inflammatory polyposis, and cancer

Question 30

Ulcerative colitis increases risk of ____ particularly with onset in childhood, pancolitis, and duration of disease \> 10 years

Answer 30

Ulcerative colitis increases risk of colon cancer particularly with onset in childhood, pancolitis, and duration of disease \> 10 years * Invasive cancer preceded by the development of dysplasia: low grade dysplasia, high grade dysplasia, indefinite for dysplasia

Question 31

\_\_\_\_ are abnormal growths of tissue projecting from a mucous membrane and can be ____ or \_\_\_\_

Answer 31

Polyps are abnormal growths of tissue projecting from a mucous membrane and can be sessile or pedunculated (with stalk) * Non-neoplastic: hyperplastic, inflammatory, hamartomatous * Neoplastic: tubular adenoma, villous adenoma, tubulovillous adenoma, sessile serated adenoma

Question 32

Hyperplastic polyps \_\_\_\_, \_\_\_\_, \_\_\_\_, and \_\_\_\_

Answer 32

Hyperplastic polyps occur often in the left colon, are small (\< 5 mm), include mature goblet cells and absorptive cells, and include a serration * Serration (star shaped): typically restricted to approximately the upper third of crypts

Question 33

Inflammatory polyp is composed of \_\_\_\_

Answer 33

Inflammatory polyp is composed of a non-neoplastic mixture of epithelial, stromal, and inflammatory cells * Related to IBD, prolapse type inflammatory polyps, and solitary rectal ulcer syndrome

Question 34

Describe pathophysiology of solitary rectal ulcer syndrome

Answer 34

Solitary rectal ulcer syndrome pathophysiology 1. Impaired relaxation of anorectal sphincter 2. Recurrent abrasion and ulceration of the mucosa 3. Inflammatory polyp 4. Entrapment of polyp in fecal stream 5. Mucosal prolapse

Question 35

Solitary rectal ulcer syndrome presents with the triad of \_\_\_\_, \_\_\_\_, and \_\_\_\_

Answer 35

Solitary rectal ulcer syndrome presents with the triad of rectal bleeding, mucus discharge, and an inflammatory lesion / polyp

Question 36

Hamartamous polyps are ____ composed of ____ often with \_\_\_\_

Answer 36

Hamartamous polyps are benign tumor-like nodules composed of an overgrowth of tissue present in the area often with one element predominating * Sporadic: juvenile polyp, Peutz-Jeghers polyp * Components of various genetic / acquired syndromes

Question 37

Juvenile polyps occur often \_\_\_\_, are most often located in ____ and present with \_\_\_\_, and can be ____ or \_\_\_\_

Answer 37

Juvenile polyps occur often in children \< 5 years, are most often located in rectum and present with bleeding, and can be sporadic or syndromic juvenile polyposis * Syndromic juvenile polyposis can undergo malignant transformation -\> increased risk of colonic adenocarcinoma

Question 38

Syndromic juvenile polyposis can undergo ____ transformation leading to an increased risk of \_\_\_\_

Answer 38

Syndromic juvenile polyposis can undergo malignant transformation leading to an increased risk of colonic adenocarcinoma

Question 39

Peutz-Jeghers syndrome is caused by \_\_\_\_, results in \_\_\_\_, and increases risk of \_\_\_\_

Answer 39

Peutz-Jeghers syndrome is caused by STK11 gene mutation, results in GI hamartomatous polyps and mucocutaneous hyperpigmentation, and increases risk of malignancies * Malignancies: breast and GI (pancreas) * Complex architecture w/ smooth muscle bundles cutting through lamina propria

Question 40

Juvenile polyposis involves mutation in \_\_\_\_, while Peutz-Jeghers syndrome involves mutations in \_\_\_\_

Answer 40

Juvenile polyposis involves mutation in SMAD4, while Peutz-Jeghers syndrome involves mutations in STK11

Question 41

Neoplastic polyps of the colon are precursors for \_\_\_\_

Answer 41

Neoplastic polyps of the colon are precursors for colorectal carcinoma * Classification: tubular adenoma, villous adenoma, tubulovillous adenoma, sessile serrated adenoma

Question 42

Tubular adenomas have \_\_\_\_, are mostly ____ but may ____ if large, and have increased incidence with \_\_\_\_

Answer 42

Tubular adenomas have low grade dysplasia, are mostly silent but may bleed if large, and have increased incidence with age

Question 43

Villous adenoma is characterized by \_\_\_\_, most often located in the \_\_\_\_, and are ____ and \_\_\_\_

Answer 43

Villous adenoma is characterized by epithelial proliferation arranged as slender villi, most often located in the rectum, and are often larger and sessile

Question 44

Sessile serrated adenomas often occur in the \_\_\_\_, have ____ potential, and ____ typical cytologic features of dysplasia

Answer 44

Sessile serrated adenomas often occur in the right colon, have malignant potential, and lack typical cytologic features of dysplasia * Overlap histologically with hyperplastic polyps

Question 46

Neoplastic polyps may undergo malignant transformation (adenoma-carcinoma sequence), particularly if \_\_\_\_

Answer 46

Neoplastic polyps may undergo malignant transformation (adenoma-carcinoma sequence), particularly if large Size matters!

Question 47

Risk factors for colon cancer include \_\_\_\_, \_\_\_\_, and \_\_\_\_

Answer 47

Risk factors for colon cancer include smoking, dietary factors (high fat diet, low fiber diet), and obesity

Question 48

Describe carcinoma of the colon and rectum

Answer 48

Carcinoma of the colon and rectum * Distribution: rectosigmoid \> ascending \> descending * Ascending colon -\> iron deficiency anemia, weight loss * Descending colon -\> colicky pain, partial obstruction, hematochezia * Pathology: gross (ulcerating, annular, polypoid), microscopic (adenocarcinomas\_

Question 49

Familial adenomatous polyposis results from ____ and causes \_\_\_\_

Answer 49

Familial adenomatous polyposis results from germline mutation of APC gene and causes colorectal adenocarcinoma often by age 30 * APC: tumor suppressor gene, on chromosome 5 * Autosomal dominant * Multiple tubular adenomas (\> 100) Extra-intestinal manifestations: congenital hypertrophy of retinal pigmented epithelium at birth -\> early screening * Treatment: colectomy *

Question 50

Hereditary nonpolyposis colorectal cancer (Lynch syndrome) has ____ inheritence, results from \_\_\_\_, and involves \_\_\_\_

Answer 50

Hereditary nonpolyposis colorectal cancer (Lynch syndrome) has autosomal dominant inheritence, results from mutations in genes encoding proteins responsible for detection / repair of errors during DNA replication, and involves familial clustering of cancers * DNA instability (microsatellite instability)

Question 52

Hereditary nonpolyposis colorectal cancer (Lynch syndrome) is often \_\_\_\_

Answer 52

Hereditary nonpolyposis colorectal cancer (Lynch syndrome) is often right colon cancer * Younger age than sporadic

Question 53

MLH1, MSH2, MSH6, and PMS2 mutations can result in \_\_\_\_

Answer 53

MLH1, MSH2, MSH6, and PMS2 mutations can result in hereditary nonpolyposis colorectal cancer (Lynch syndrome) * DNA instability (microsatellite instability)

Question 54

Colonic adenocarcinoma may involve \_\_\_\_

Answer 54

Colonic adenocarcinoma may involve infiltrative carcinoma invading the submucosa

Question 55

Prognostic factors in colorectal carcinoma are \_\_\_\_, \_\_\_\_, and \_\_\_\_

Answer 55

Prognostic factors in colorectal carcinoma are depth of pentration (stage), metastasis to lymph nodes or other organs (liver), and type of differentiation * Poorly differentiated and mucinous -\> poor prognosis * Prevention / screening via colonoscopy and removal of precursor