We have posted updates of the following topics:Colon > Infectious colitis > Amebic colitis
by Blaine A. Mathison, B.S., Bobbi S. Pritt, M.D., M.Sc.
Topic summary: Disease caused by infection of the large intestine with the protozoan parasite, Entamoeba histolytica. Transmission primarily by ingestion of E. histolytica cysts in fecally contaminated food or water (fecal – oral); also by sexual contact (oral – anal). Occurs worldwide but more common in tropical and subtropical regions. Definitive diagnosis of amebic colitis is made by finding trophozoites that have invaded the intestinal mucosa. Amebic colitis is treated with both an amebicidal and luminal agent.
Colon > Diverticular disease > Diverticulosis
by Bindu Challa, M.D., Martha M. Yearsley, M.D.
Topic summary: Anatomic change in the colon characterized by outpouchings of mucosa and submucosa through the muscularis. Diverticulosis can be asymptomatic or symptomatic. Highest incidence in Western world; prevalence increases with age. Occurs in weaker portions of the colonic wall where vasa recta infiltrate the circular muscle layer. Frequently is an incidental finding during colonoscopy. Treatment: symptomatic uncomplicated diverticular disease (SUDD): dietary modifications to increase fiber, use of probiotics has been proposed; antibiotics in acute complicated diverticulitis.
Gallbladder & extrahepatic bile ducts > Extrahepatic bile duct tumors > Biliary intraepithelial neoplasia
by Satyapal Chahar, M.D., Monica T. Garcia-Buitrago, M.D.
Topic summary: Biliary intraepithelial neoplasia (BilIN) is a microscopic, premalignant, noninvasive neoplastic lesion of gallbladder or bile duct. Microscopically flat or micropapillary lesion with low or high grade dysplasia. Approximately 1 – 3.5% of cholecystectomies are found to have incidental BilIN; no gender predilection. Extensive disease, involvement of Rokitansky-Aschoff sinuses and positive margin status increase the risk of recurrence. Most high grade BilIN of gallbladder can be cured by cholecystectomy.
Stains & CD markers > IDH1 (R132H)
by Chunyu Cai, M.D., Ph.D.
Topic summary: Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are metabolic enzymes that catalyze the oxidative decarboxylation of isocitrate to produce α ketoglutarate (also known as 2 oxoglutarate [2OG]), NAPDH and CO2. IDH mutant gliomas have a better prognosis than the IDH wild type counterparts. IDH1 R132H immunostain is widely used in pathology laboratories on brain tumors in order to classify diffuse gliomas and provide prognostic implications. IDH1 (R132H) mutant gliomas show diffuse cytoplasmic reactivity in all tumor cells on IDH1 R132H immunostains.