Anatomical Pathology > Surgical Pathology > High Yield Reviews > GI Tract > Small & Large Intestines (This Page)

A high yield review of

Small & Large Intestine

Pathology

Tiffany M. Graham, M.D.

(4th year Pathology Resident)

Table of Contents.

Histology of the GI Tract.

Benign Conditions.

Patterns of Colitis.

Colon Polyps

Cancer.

Cancer Grading & Staging.

SEE ALL TOPICS

 

Recent Posts.

 
 

The Basics.

A Quick Histology Tour of the GIT

Before one can learn pathology, you must master the art of histology. Here is a quick overview of some general themes seen in the histology of the GI tract. Be sure to read this post before looking into further details about each portion of the intestinal tract!  

 

Histology of the Small Intestines 

CLICK ON TITLE TO SEE FULL POST (contains tons of histology pictures of that organ)

CLICK ON IMAGE FOR MAGNIFIED VIEW

Histology of the Large Intestines

Slide3.JPG

Food travels from the small intestines through the colon as follows: 

1. Cecum

2. Ascending (right) colon

3. Transverse colon

4. Descending (left) colon

5. Sigmoid colon

6. Rectum

7. Anus (skin)

This post contains high yield findings to help identify your location in the GIT.             Continue reading...

 

Benign Conditions.

 

  • Congenital Anomalies

    • Duplication

    • Malrotation

    • Omphalocele

    • Gastroschisis

    • Meckel Diverticulum

    • Congenital Aganglionic Megacolon (Hirschsprung Disease)

  • Diverticular Disease​

  • Intestinal Obstruction (benign etiology)

    • Hernias

    • Adhesions

    • Intussusception

    • Volvulus

  • Enzymatic deficiencies/Autoimmune diseases

    • Celiac Disease

    • Lactase Deficiency

    • Abetalipoproteinemia

  • Vascular Disorders
    • Ischemic Bowel Disease

    • Angiodysplasia

    • Hemorrhoids​

 

  • Diarrhea Etiologies

    • Infectious organisms

    • Type (Secretory, Osmotic, Exudative)

    • Malabsorption

    • Enzyme deficiencies

    • Autoimmune inflammation

    • Antibiotic-associated injury

  • Inflammatory Conditions

    • Necrotizing Enterocolitis

    • Collagenous & Lymphocytic Colitis

    • Graft vs. Host disease (Transplant)

    • Drug-induced injury (NSAIDs)

    • Radiation enterocolitis

    • Neutropenic colitis (Typhlitis)

    • Diversion Colitis

    • Colitis Cystica Profunda (Solitary Rectal Ulcer Syndrome)

  • Inflammatory Bowel Disease

    • Idiopathic Inflammatory Bowel Disease (IBD)

    • Irritable bowel syndrome

    • Ischemic colitis

    • Celiac Disease

    • Crohn Disease

    • Ulcerative Colitis​

  • Infectious Organisms

    • Viruses

      • Adenovirus 

      • Astrovirus

      • Calicivirus (Norwalk)

      • HIV

      • Rotavirus

    • Bacteria

      • Toxigenic (Vibrio cholerae, E. coli)

      • Enteroinvasive (Shigella, Salmonella, Yersinia, Campylobacter, Enteroinvasive E. coli)

      • Antibiotic-associated/Pseudomembranous Colitis- C. difficile)

      • Tropical (Postinfectious) Sprue

      • Whipple Disease (Tropheryma whippelii)

      • Dysentery

    • Parasites

      • Nematodes (Roundworms)

        • Ascaris

        • Strongyloides

        • Hookworms

        • Pinworms (Enterbius vermicularis)

        • Whipworms (Trichuris Trichura)

      • Cestodes

      • Protozoa

        • Entamoeba histolytica

        • Giardia Lamblia

        • Microsporidia

        • Cryptosporidia

        • Isospora belli

 

The Many Patterns of Colitis...

Acute (Active) Colitis Pattern

  • Infection

  • Medication

  • Inflammatory Bowel Disease​

Focal Active Colitis Pattern

  • Acute Self-limited Colitis

    • Infection

    • Medication

    • Chemicals or Irritants

  • Inflammatory Bowel Disease

  • Ischemic Colitis

  • Irritable Bowel Syndrome

  • Antibiotic-associated Colitis

  • Nonsteroidal Anti-inflammatory Drugs

  • Bowel Preparatory Artifact​

Chronic (Inactive) Colitis Pattern

  • Inflammatory Bowel Disease

  • Diverticular Disease

  • Diversion-associated Colitis

  • Syphilitic and Lymphogranuloma Venereum Proctocolitis

  • Cord Colitis Syndrome

  • Ipilimumab Colitis

  • Resins​

Lymphocytic Pattern

  • Lymphocytic Colitis

  • Collagenous Colitis

  • Medications

  • Viral Infection

 

Eosinophilia Pattern

  • Idiopathic Eosinophilic Colitis

  • Inflammatory Bowel Disease

  • Allergy

  • Medications

  • Infection

  • Parasite

  • Collagen Vascular Disorder and Vasculitis

 

Granulomatous Pattern

  • Inflammatory Bowel Disease

  • Nonspecific Mucosal Injury

  • Diverticular Disease

  • Infections

  • Medication

  • Sarcoidosis

  • Vascular Injury

  • Pneumatosis Cystoides Intestinalis

  • Autoimmune Diseases

  • Cord Colitis Syndrome

  • Lymphoproliferative Disorders

 

Ischemic Colitis Pattern

  • Ischemia

  • Infection

  • Medication

 

Pseudomembranous Pattern

  • Ischemia

  • Clostridium difficile Colitis and Other Infections​

 

Pigments and Extras

  • Melanosis Coli

  • Tattoo Pigment

  • Air Artifact

  • Pneumatosis Cystoides Intestinalis

  • Muciphages

  • Resins

 

Near Misses

  • Endometriosis

  • Benign Signet Ring Cell Change

  • Pulse Granulomata

  • Apoptotic Colopathy

  • Spirochetosis

 

Cancer.

Currently in progress... Check back soon!

Currently in progress... Check back soon!

 
 

Tips for [future] Pathologists.

Currently in progress... Check back soon!

Currently in progress... Check back soon!

 

Cancer Grading & Staging.

Currently in progress... Check back soon!

Currently in progress... Check back soon!

 

How to Gross a Colon Specimen.

Currently in progress... Check back soon!

Currently in progress... Check back soon!

Click on a topic below to learn more)

 

The Basics

 

 

 

Benign Conditions 

 

  • Congenital Anomalies

    • Duplication

    • Malrotation

    • Omphalocele

    • Gastroschisis

    • Meckel Diverticulum

    • Congenital Aganglionic Megacolon (Hirschsprung Disease)

  • Inflammatory Conditions

    • Necrotizing Enterocolitis

    • Collagenous & Lymphocytic Colitis

    • Graft vs. Host disease (Transplant)

    • Drug-induced injury (NSAIDs)

    • Radiation enterocolitis

    • Neutropenic colitis (Typhlitis)

    • Diversion Colitis

    • Colitis Cystica Profunda (Solitary Rectal Ulcer Syndrome)

  • Inflammatory Bowel Disease

    • Idiopathic Inflammatory Bowel Disease (IBD)

    • Irritable bowel syndrome

    • Ischemic colitis

    • Celiac Disease

    • Crohn Disease

    • Ulcerative Colitis

  • Diarrhea Etiologies

    • Mechanisms of action 

      • Infectious organisms

      • Type (Secretory, Osmotic, Exudative)

      • Malabsorption

      • Enzyme deficiencies

      • Autoimmune inflammation

      • Antibiotic-associated injury

    • Common Infectious Organisms known to cause diarrhea

      • Viruses

        • Adenovirus 

        • Astrovirus

        • Calicivirus (Norwalk)

        • HIV

        • Rotavirus

      • Bacteria

        • Toxigenic (Vibrio cholerae, E. coli)

        • Enteroinvasive (Shigella, Salmonella, Yersinia, Campylobacter, Enteroinvasive E. coli)

        • Antibiotic-associated/Pseudomembranous Colitis- C. difficile)

        • Tropical (Postinfectious) Sprue

        • Whipple Disease (Tropheryma whippelii)

        • Dysentery

      • Parasites

        • Nematodes (Roundworms)

          • Ascaris

          • Strongyloides

          • Hookworms

          • Pinworms (Enterbius vermicularis)

          • Whipworms (Trichuris Trichura)

        • Cestodes

        • Protozoa

          • Entamoeba histolytica

          • Giardia Lamblia

          • Microsporidia

          • Cryptosporidia

          • Isospora belli

  • Diverticular Disease

  • Intestinal Obstruction (benign etiology)

    • Hernias

    • Adhesions

    • Intussusception

    • Volvulus

  • Enzymatic deficiencies/Autoimmune diseases

    • Celiac Disease

    • Lactase Deficiency

    • Abetalipoproteinemia

  • Vascular Disorders
    • Ischemic Bowel Disease

    • Angiodysplasia

    • Hemorrhoids

 

 

 

 

Neoplastic Conditions

  • Small Intestine Tumors

  • Non-neoplastic (benign) polyps

  • Neoplastic Epithelial Lesions

  • Mesenchymal Lesions

  • Lymphoma

 

 

Essentials for [future] Pathologists

 

  • How to gross a benign resection specimen

  • How to gross a tumor resection specimen

  • How to grade & stage cancer

  • How to sign-out the case

 

Index of High Yield Posts.

These posts contain high yield information collected from various educational resources including textbooks, journal articles, educational websites and more. They are intended for educational use only. I strongly believe the spreading of knowledge and depth of learned information should be encouraged in today's society rather than coveted. However, membership is required to view these posts  and should be used solely for educational purposes only. It is FREE to sign up

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DISCLAIMER: THIS WEBSITE DOES NOT PROVIDE MEDICAL ADVICE

These posts contain high yield information collected from various educational resources including textbooks, journal articles, educational websites and more. They are intended for educational use only and should NOT be taken as medical advice. I strongly believe the spreading of knowledge and depth of learned information should be encouraged in today's society rather than coveted. Membership is required to view these posts  and should be used solely for educational purposes only.