Gastrointestinal Tract

Pseudomembranous colitis

This is an example of pseudomembranous enterocolitis. The mucosal surface of the colon seen here is hyperemic and is partially covered by a yellow-green exudate. The mucosa itself is not eroded.

Pseudomembranous colitis

There are multiple, discrete white plaques of purulent exudate on the mucosal surface. The patient was taking ampicillin.

Pseudomembranous colitis

Neutrophils in lamina propria
Superficial damaged crypts distended by a mucopurulent exudate
mushrooming or volcano cloud
Eruption


Postmortem specimen of small intestine. There are multiple oval ulcers running transversely across the bowel (arrows). The patient died from untreated disseminated tuberculosis.
Intestinal TB


Characteristic rounded, slightly elevated areas of the mucosa with irregular yellow necrotic centers surrounded by edematous hyperemic tissue. Some times Hgic centres The intervening mucosal folds have a mostly normal appearance, although one segment is congested and edematous.
Amebic colitis

Amebic colitis

There is characteristic flask shaped ulcer extending into the submucosa

Amebic colitis

Numerous ameba trophs causing lysis (histolytica) of the mucosa. Trophs are pale stained; Inflammatory cells dark stained

Amebic colitis

Amebae are round PAS positive organisms. Stain PAS

Giardia lamblia

Giardia lamblia infection of the small intestine. The small pear-shaped trophozoites live in the duodenum and become infective cysts that are excreted. They produce a watery diarrhea. A useful test for diagnosis of infectious diarrheas is stool examination for ova and parasites.