NON-NEOPLASTIC DISORDERS OF THE GASTROINTESTINAL TRACT (AFIP ATLASES OF TUMOR AND NON-TUMOR PATHOLOGY, SERIES 5, VOL. 4)

1. Normal Gross and Histologic Features of the Gastrointestinal Tract1
• The Normal Esophagus1
• Anatomy1
• Histology 2
• The Normal Stomach. . 2
• Anatomy2
• Histology 4
• The Normal Small Bowel . . 6
• Anatomy6
• Histology 8
• The Normal Colorectum. . 10
• Anatomy10
• Histology 11
• The Normal Appendix . 12
• Anatomy12
• Histology 12
• The Normal Anus . . 14
• Anatomy14
• Histology 15
2. Diseases of the Esophagus19
• Congenital and Acquired Structural Abnormalities. . 19
• Esophageal Atresia and Tracheoesophageal Fistula19
• Esophageal Stenosis. 20
• Esophageal Rings and Webs20
• Esophageal Cysts 21
• Diverticula. . 22
• Intramural Pseudodiverticulosis 24
• Heterotopias24
• Motility Disorders and Infiltrative Diseases26
• Primary Achalasia. . 26
• Secondary Achalasia28
• Chagas Disease. 30
• Progressive Systemic Sclerosis . . 31
• Other Disorders with Abnormal Manometric Findings 32
• Causes of Esophageal Hemorrhage32
• Varices . . 32
• Mucosal Tears and Esophageal Rupture34
• Inflammatory Conditions of the Esophagus . . 34
• Corrosive Esophagitis. . 34
• Gastroesophageal Reflux Disease. . 36
• Eosinophilic Esophagitis 40
• Lymphocytic Esophagitis. . 46
• Drug-Induced Injury 48
• Infectious Esophagitis. 53
• Candida Esophagitis53
• Herpesvirus Esophagitis54
• Cytomegalovirus Esophagitis. . 56
• Idiopathic HIV-Associated Ulcers. . 59
• Desquamating Disorders. . 61
• Esophagitis Dissecans Superficialis . 61
• Acute Esophageal Necrosis. 62
• Other Pauci-Inflammatory Conditions that Cause Esophageal Desquamation65
• Mucocutaneous Bullous Diseases Involving the Esophagus66
• Barrett Esophagus. . 69
• Polyps of the Esophagus. . 78
• Glycogenic Acanthosis. 78
• Hyperplastic Polyp. 79
• Squamous Papilloma80
• Polypoid Fibroadipose Tumors of the Esophagus. . 81
3. Diseases of the Stomach. . 95
• Congenital and Acquired Structural Abnormalities. . 95
• Gastric Atresia . . 95
• Pyloric Stenosis. 95
• Duplication Cysts. . 96
• Diverticula. . 97
• Pancreatic Heterotopia and Metaplasia99
• Motility Disorders. 99
• Gastroparesis99
• Bezoar. . 101
• Pauci-Inflammatory Gastropathies103
• Portal Hypertensive Gastropathy. . 103
• Gastric Antral Vascular Ectasia. 105
• Acute Hemorrhagic Gastropathy. . 106
• Chemical Gastropathy. 108
• Bile Reflux Gastropathy110
• Drug-Induced Gastric Injury. . 113
• Mucosal Calcinosis. 113
• Iron Pill Gastropathy114
• Doxycycline-Related Injury118
• Therapy-Related Gastropathies118
• Graft-versus-Host Disease. . 118
• Radiation- and Chemotherapy-Related Gastropathy . . 121
• Selective Internal Radiation Therapy-Related Gastropathy125
• Inflammatory Diseases of the Stomach 126
• Helicobacter-Associated Chronic Gastritis . . 126
• Autoimmune Gastritis. . 133
• Collagenous Gastritis. . 136
• Lymphocytic Gastritis . . 140
• Granulomatous Gastritis142
• Phlegmonous Gastritis. 144
• Sarcina Ventriculi and Related Organisms. . 146
• Hypertrophic Gastropathies146
• Menetrier Disease. . 146
• Zollinger-Ellison Syndrome147
• Gastric Polyps. . 150
• Xanthoma . . 150
• Fundic Gland Polyp152
• Hyperplastic Polyp. 155
• Non-Neoplastic Mimics of Diffuse-Type Gastric Carcinoma. . 157
• Signet Ring Cell Change (Pseudosignet Ring Cells) 157
• Macrophages161
4. Diseases of the Small Intestine and Colorectum. 173
• Congenital Abnormalities. 173
• Atresias and Stenoses. . 173
• Duplication Cysts. . 173
• Congenital Diverticula and Remnants of the Vitelline Duct. . 174
• Heterotopias177
• Disorders of Infancy and Early Childhood179
• Microvillus Inclusion Disease . . 179
• Congenital Tufting Enteropathy183
• Abetalipoproteinemia . . 186
• Enteroendocrine Cell Dysgenesis. . 187
• Intestinal Aganglionosis189
• Cystic Fibrosis. . 190
• Necrotizing Enterocolitis191
• Inborn Errors of Metabolism192
• Primary Intestinal Lymphangiectasia . . 194
• Protein Allergy. . 195
• Vascular Abnormalities and Ischemic Enterocolitis. . 196
• Caliber-Persistent Artery 196
• Telangiectasia. . 197
• Angiodysplasia. 199
• Arteriovenous Malformation. . 200
• Hereditary Hemorrhagic Telangiectasia202
• Blue Rubber Bleb Nevus Syndrome. 203
• Portal Hypertensive Enterocolopathy. . 204
• Ischemic Enterocolitis . . 205
• Polyarteritis Nodosa210
• Antineutrophil Cytoplasmic Antibody-Associated Vasculitis. 211
• IgA-Associated Vasculitis 214
• Behçet Disease . . 216
• Enterocolic Lymphocytic Phlebitis . 217
• Idiopathic Myointimal Hyperplasia of Mesenteric Veins . . 218
• Other Types of Vasculitis and Vasculopathy. . 221
• Medication-Related Enterocolopathies and Enterocolitides . . 223
• Antibiotic Agents. . 223
• Bisphosphonates 224
• Iron Deposition and Related Injury224
• Melanosis Coli. . 226
• Preparatory Effects. 226
• Nonsteroidal Anti-Inflammatory Drugs226
• Ion Exchange Resins and Sequestrants. 231
• Olmesartan and Related Compounds. . 233
• Medications that Affect the Cell Cycle. 234
• Mycophenolate-Induced Gastrointestinal Injury. . 236
• Immune Checkpoint Inhibitors238
• Idelalisib241
• Other Chemotherapeutic Agents. . 242
• Medications that Cause Ischemic Injury. . 243
• Other Therapy-Related Enterocolopathies and Enterocolitides. . 244
• Graft-versus-Host Disease. . 244
• Cord Colitis Syndrome. 247
• Neutropenic Enterocolitis . . 247
• Radiation Enterocolitis. 249
• Infections of the Small Bowel and Colon. 253
• Acute Infectious Enterocolitis, Inflammatory Pattern. 253
• Acute Infectious Colitis, Ischemic/Hemorrhagic Pattern . . 253
• Pseudomembranous Colitis256
• Other Bacterial Enterocolitis258
• Viral Enterocolitis. . 266
• Fungal Enterocolitis269
• Protozoal Infections272
• Helminthic Infections. . 283
• Proctitis Due to Sexually Transmitted Infections. . 289
• Other Inflammatory Conditions and Structural Abnormalities. . 291
• Peptic Duodenitis and Duodenal Ulcers 291
• Tropical Sprue. . 293
• Small Intestinal Bacterial Overgrowth. 296
• Secondary Intestinal Lymphangiectasia 296
• Small Intestinal Diverticulosis. 297
• Colonic Diverticulosis and Related Inflammatory Conditions299
• Diversion Colitis and Diversion-Related Changes. 304
• Stercoral Ulcer . . 305
• Pneumatosis Intestinalis 307
• Mucosal Prolapse and Solitary Rectal Ulcer Syndrome308
• Inflammatory Cap Polyposis310
• Stent-Related Pseudopolyposis. 314
5. Immune-Mediated Diseases with Systemic Manifestations . . 333
• Celiac Disease and Related Disorders. . 333
• Celiac Disease. . 333
• Refractory Sprue339
• Ulcerative Jejunoileitis. 339
• Collagenous Sprue. . 341
• Idiopathic Inflammatory Bowel Disease. . 341
• Ulcerative Colitis341
• Crohn Disease . . 349
• Pouch Inflammation Following Ileal Pouch-Anal Anastomosis354
• Collagenous Colitis . 360
• Lymphocytic Colitis364
• Eosinophilc Gastroenteritis. 366
• Autoimmune Enteropathy. 368
6. Systemic Disorders with Gastrointestinal Manifestations 379
• Primary Immunodeficiencies. . 379
• Common Variable Immunodeficiency. 379
• Selective IgA Deficiency382
• Chronic Granulomatous Disease. . 382
• Connective Tissue Disorders. . 383
• Ehlers-Danlos Syndrome Type IV. . 383
• Collagen Vascular Diseases . 385
• Deposition Diseases387
• Cryoglobulinemia. . 387
• Amyloidosis. 388
• Lymphoplasmacytic Lymphoma. . 390
• Light Chain Deposition Disease 392
• Non-Neoplastic Polyposis Syndromes . 392
• Sporadic Hamartomatous Polyps. . 393
• Juvenile Polyposis Syndrome. . 393
• Peutz-Jeghers Syndrome395
• PTEN Hamartoma-Tumor Syndrome. . 397
• Cronkhite-Canada Syndrome . . 398
• Ganglioneuromas and Ganglioneuromatosis. . 399
• Miscellaneous Disorders399
• Malakoplakia399
• Endometriosis. . 402
7. Diseases of the Veriform Appendix. . 409
• Congenital and Acquired Structural Anomalies. . 409
• Appendiceal Agenesis. . 409
• Appendiceal Duplication. . 409
• Appendiceal Diverticula and Diverticulitis. 409
• Mechanical Abnormalities of the Appendix. . 411
• Intussusception . 411
• Inflammatory Conditions of the Appendix412
• Acute Appendicitis. 412
• Stump Appendicitis. 418
• Eosinophilic Appendicitis . . 418
• Interval Appendicitis419
• Chronic Appendicitis. . 419
• Chronic Idiopathic Inflammatory Bowel Disease. . 422
• Specific Bacterial Causes of Appendicitis. . 424
• Viral Appendicitis. . 426
• Fungal Infection428
• Parasitic Infection. . 428
• Miscellaneous Conditions. 430
• Mucocele 430
• Myxoglobulosis . 432
• Fibrous Obliteration432
• Periappendicitis. 432
• Endometriosis. . 435
• Endosalpingiosis435
• Deciduosis of the Appendix436
• Non-Neoplastic Appendiceal Polyps436
8. Diseases of the Anus . . 443
• Congenital and Acquired Structural Anomalies. . 443
• Anorectal Malformations. . 443
• Tailgut Cyst . 444
• Ectopic Tissues. . 445
• Hemorrhoids. . . 447
• Fissures. 449
• Fistulae. 450
• Polyps of the Anus . 452
• Fibroepithelial Polyp452
• Inflammatory Cloacogenic Polyp. . 452
• Condyloma Acuminatum . . 454
• Inflammatory Diseases of the Anus 457
• Herpes Simplex Virus. . 457
• Syphilis. 459
• Lymphogranuloma Venereum. 462
• Granuloma Inguinale. . 463
• Crohn Disease . . 464
• Index. . 469

Pathologists play a particularly important role in the care of patients with persistent gastrointestinal symptoms, especially those who are immunosuppressed, suffer from immune-mediated conditions, or undergo treatment for malignancies. They must be able to focus on key features present in biopsy material in order to narrow the differential diagnosis and facilitate patient management. This atlas addresses these needs in a succinct and pragmatic fashion. It describes practical approaches to the diagnosis of inflammatory gastrointestinal disorders and provides helpful criteria to distinguish between newly recognized causes of esophagitis and gastritis.