Gastrointestinal Tract

Gastrointestinal Tract GIT Pathology Esophagus Intestines Peritoneum Stomach Appendix Intestines - Pathology Appendix Acute Appendicitis Tumors • Appendix • Acute appendicitis • MC in adolescents & young adults • Characterized by= Obstruction of lumen  MC by fecolith – Raised intraluminal pressure – Ischemic injury & Bacterial invasion • Morphology: – Acute supporative appendicitis • Hyperemia, edema & PML infiltration of all layers of the wall to the peritoneum – Acute gangrenous appendicitis • Thrombosis of appendicular vessels  gangrene  diffuse septic peritonitis. – Localized or generalized peritonitis • When becomes covered by fibrino-purulent exudate • Clinical features =deceptively minimal in old age • Complications: perforation, pylephlebitis, liver abscess • Appendix • Tumors of the appendix • 1. Mucocele: – Characterized by: • Distension of the appendiceal lumen by mucinous secretion. – Caused by: • Non -Neoplastic - Mucosal hyperplasia • Neoplastic (benign)- Mucinous cystadenoma • Neoplastic (Malignant) - Mucinous cystadenocarcinoma (fatal); may rupture  peritoneal implants, produce “pseudomyxoma peritonei”. • 2. Carcinoid: – MC tumor of appendix – Almost always benign & discovered accidentally on appendicectomy (curative). • 3. Carcinoma: Adenocarcinomas, identical to their intestinal counterparts Other conditions produce “pseudomyxoma peritonei”. Intestines - Pathology Peritoneum Inflammation Tumors • Appendix • Peritonitis • Sterile Peritonitis: – Caused by chemical irritation by bile, pancreatic juice, endometriosis (blood), ruptured ovarian cysts (dermoid) or introduction of chemical substances for diagnostic (laparoscopy, salpingo-graphy) or therapeutic procedures (peritoneal dialysis) • Septic Peritonitis: – Bacterial infection of the peritoneum from acute appendicitis, ruptured PU, acute cholecystitis, diverticulitis, bowel strangulation, acute salpingitis, or through evacuation of ascitic fluid or peritoneal dialysis. – localized (loculated abscesses) & may heal by fibrous adhesions  chronic obstruction • Sclerosing Retroperitonitis: – Idiopathic • May be related to Anti – migraine drugs (methysergide) • or may be autoimmune. – Characterized by = Excessive fibrous tissue proliferation (fibromatosis) – compromising retroperitoneal structures (ureters  hydronephrosis). • Peritoneal cysts • Mesenteric Cysts= Caused by blocked lymphatics, enteric diverticula, postinfectious cysts, postpancreatitis pseudocysts, or neoplastic cysts. • Peritoneal tumors • 1. Primary = rare, – Mesothelioma, & is related to past asbestos exposure, identical to its counterpart in the pleura • 2. Secondary = Very common, – from advanced cancer of any abdominal viscera, e.g. cancer stomach, colon, small intestine, pancreas, liver, gallbladder, uterus & breast – Diffuse seeding of the peritoneal cavity  malignant effusions (mainly ovarian) – Cancer cells can be detected in the peritoneal fluid by cytological examination Case - 5 • 20-year-old woman presented to the emergency room with only a one day history of lower abdominal pain, nausea with anorexia, and fever. On physical examination, there was periumbilical pain. Under active observation over the next couple of hours, the pain migrated to the right lower quadrant, with rebound tenderness. Her vital signs showed T 38.5 C, P 90, R 18, and BP 110/70 mm Hg. Her WBC count was 11,500 with 76% polys, 6% bands, 14% lymphs, and 4% monos. A pregnancy test was negative. A stool sample was negative for occult blood. A urinalysis was normal. The radiographic finding on abdominal CT scan is seen. A laparoscopic procedure was performed and the gross appearance of the lesion is shown. The microscopic appearance is seen. 5.1 5.2 5.3 5.4