1. Gastrointestinal System

2. Esophagus

3. This is a normal esophagus with the usual white to tan smooth mucosa seen at the left. The gastroesophageal junction (not an anatomic sphincter) is at the center, and the stomach is at the right.

4. This is normal esophageal squamous mucosa at the left, with underlying submucosa. The muscularis is at the right.

5. This is Candida esophagitis
This is Candida esophagitis. Tan-yellow plaques are seen in the lower esophagus, along with mucosal hyperemia. The same lesions are also seen at the upper right in the stomach.

6. Acute esophagitis is manifested here by infiltrating neutrophils to the squamous mucosa as well as submucosa.

7. The lower esophagus here shows sharply demarcated ulcerations that have a brown-red base, contrasted with the normal pale white esophageal mucosa at the far left.

8. An esophageal ulcer is seen here microscopically to have a sharp margins. The ulcer base at the left shows loss of overlying squamous epithelium with only necrotic debris remaining.

9. Here are two more sharply demarcated "punched out" ulcerations of the mid esophagus.

12. Barrett's esophagus in which there is gastric-type mucosa above the gastroesophageal junction. Note the columnar epithelium to the left and the squamous epithelium at the right.

13. At the lower end of the esophagus (which has been turned inside out at autopsy) are linear dark blue submucosal dilated veins known as varices. In patients with portal hypertension (usually secondary to liver cirrhosis from chronic alcoholism), the submucosal esophageal veins become dilated (form varices). These varices are prone to bleed.

14. Esophageal variceal bleeding
Esophageal variceal bleeding. Here is another varix near the gastroesophageal junction that is dark red black because it has been bleeding. (The esophagus has been turned inside out.)

15. Inflammation and hemorrhage is seen here in the region of a ruptured varix of the esophagus.

16. This radiograph taken following barium swallow demontrates a stricture in the lower esophagus, with pooling of the contrast above the point of stricture. Such stricture may complicate conditions such as scleroderma, gastroesophageal reflux disease, or carcinoma.

17. History of smoking and/or alcoholism is often present in patients with esophageal squamous carcinoma, while a history of Barrett's esophagus precedes development of esophageal adenocarcinoma in many cases. Here, an ill-defined mass at the gastroesophageal junction produces mucosal ulceration and irregularity, which led to the clinical symptoms of pain and difficulty swallowing.

18. This irregular reddish, ulcerated exophytic mid-esophageal mass as seen on the mucosal surface is a squamous cell carcinoma..

19. At high power, these infiltrating nests of neoplastic cells have abundant pink cytoplasm and distinct cell borders typical for squamous cell carcinoma. Esophageal carcinomas are not usually detected early and, therefore, have a very poor prognosis.

20. Stomach

21. This is the normal appearance of the stomach

22. This is the normal appearance of the gastric antrum extending to the pylorus at the right of center. The first portion of the duodenum (duodenal bulb) is at the far right..

23. This is the normal appearance of the gastric fundal mucosa, with short pits lined by pale columnar mucus cells leading into long glands which contain bright pink parietal cells that secrete hydrochloric acid.

24. This is an acute gastritis with a diffusely hyperemic gastric mucosa
This is an acute gastritis with a diffusely hyperemic gastric mucosa. There are many causes for acute gastritis.

25. Here are some larger areas of gastric hemorrhage that could best be termed "erosions" because the superficial mucosa is eroded away. The findings here fit with acute erosive gastritis.

26. At high power, gastric mucosa demonstrates infiltration by neutrophils
At high power, gastric mucosa demonstrates infiltration by neutrophils. This is acute gastritis

27. A 1 cm acute gastric ulcer is shown here in the upper fundus
A 1 cm acute gastric ulcer is shown here in the upper fundus. The ulcer is shallow and sharply demarcated, with surrounding hyperemia. It is probably benign. However, all gastric ulcers should be biopsied to rule out a malignancy.

28. Here is a much larger 3 x 4 cm gastric ulcer that led to the resection of the stomach shown here. This ulcer is much deeper with more irregular margins. Complications of gastric ulcers (either benign or malignant) include pain, bleeding, perforation, and obstruction.

29. Microscopically, the ulcer here is sharply demarcated, with normal gastric mucosa on the left falling away into a deep ulcer whose base contains infamed, necrotic debris. An arterial branch at the ulcer base is eroded and bleeding.

30. Infection with Helicobacter pylori
Infection with Helicobacter pylori. This small curved to spiral rod-shaped bacterium is found in the surface epithelial mucus of most patients with active gastritis. The rods are seen here with a methylene blue stain.

31. Helicobacter pylori, gastric biopsy, silver stain on left, giemsa stain on right.

32. Helicobacter pylori Causes 70% of gastric peptic ulcers
Causes 95% of duodenal peptic ulcers
Causes chronic gastritis
Causes gastric carcinomas
Causes MALT lymphomas

33. Stress ulcers?? Cushing's ulcer Vs. Curling's ulcer

34. GASTRIC TUMORS
BENIGN
MALIGNANT

35. Gastric neoplasia is not uncommon. Here is a gastric adenocarcinoma
Gastric neoplasia is not uncommon. Here is a gastric adenocarcinoma. In the U.S., most gastric cancers are discovered at a late stage when the neoplasm has invaded and/or metastasized. ALL gastric ulcers and ALL gastric masses must be biopsied, because it is not possible to tell from gross appearance alone which are benign and which are malignant. In contrast, virtually all duodenal peptic ulcers are benign.

36. Here is a gastric ulcer in the center of the picture
Here is a gastric ulcer in the center of the picture. It is shallow and is about 2 to 4 cm in size. This ulcer on biopsy proved to be malignant, so the stomach was resected as shown here.

37. At higher magnification, the neoplastic glands of gastric adenocarcinoma demonstrate mitoses, increased nuclear/cytoplasmic ratios, and hyperchromatism.

38. At high power, this gastric adenocarcinoma is so poorly differentiated that glands are not visible. Instead, rows of infiltrating neoplastic cells with marked pleomorphism are seen. Many of the neoplastic cells have clear vacuoles of mucin.

39. This is a signet ring cell pattern of adenocarcinoma in which the cells are filled with mucin vacuoles that push the nucleus to one side, as shown at the arrow.

40. Small Intestine

41. This is the normal appearance of small intestinal mucosa with long villi that have occasional goblet cells. The villi provide a large area for digestion and absorption.

42. This is an adhesion between loops of small intestine
This is an adhesion between loops of small intestine. Such adhesions are typical following abdominal surgery. More diffuse adhesions may also form following peritonitis.

43. The dark red infarcted small intestine contrasts with the light pink viable bowel. This is one complication of adhesions from previous surgery. The trapped bowel has lost its blood supply.

44. The mucosal surface of the bowel seen here shows necrosis with hyperemia extending all the way through the mucosa. The submucosa and muscularis, however, are still intact.

45. At higher magnification with more advanced necrosis, the small intestinal mucosa shows hemorrhage with acute inflammation in this case.

46. Seen here at the ileocecal valve is a tumor that has a faint yellowish color. This is a carcinoid tumor.

47. The carcinoid tumor is seen here to be a discreet, though not encapsulated, mass of multiple nests of small blue cells in the submucosa.

48. At high magnification, the nests of carcinoid tumor have a typical endocrine appearance with small round cells having small round nuclei and blue cytoplasm.

49. This is a leiomyosarcoma of the small bowel
This is a leiomyosarcoma of the small bowel. As with sarcomas in general, this one is big and bad.

50. Seen here is the most common congenital anomaly of the GI tract--a Meckel's diverticulum.

51. The small intestinal mucosa at high magnification shows marked chronic inflammation in celiac sprue. Infiltration with lymphocytes and plasma cells.

52. Inflammatory Bowel Disease

53. Crohn's disease involving the small intestine
Crohn's disease involving the small intestine. Here, the mucosal surface demonstrates an irregular nodular appearance (cobblestone appearance) with hyperemia and focal superficial ulceration.

54. Microscopically, Crohn's disease is characterized by transmural inflammation. Here, inflammatory cells extend from mucosa through submucosa and muscularis.

55. At high magnification the granulomatous nature of the inflammation of Crohn's disease is demonstrated here with epithelioid cells, giant cells, and many lymphocytes. Special stains for organisms are negative.

56. One complication of Crohn's disease is fistula formation
One complication of Crohn's disease is fistula formation. Seen here is a fissure extending through mucosa at the left into the submucosa toward the muscular wall, which eventually will form a fistula.

57. This gross appearance is characteristic for ulcerative colitis
This gross appearance is characteristic for ulcerative colitis. The most intense inflammation begins at the lower right in the sigmoid colon and extends upward and around to the ascending colon. At the lower left is the ileocecal valve with a portion of terminal ileum that is not involved. Inflammation with ulcerative colitis tends to be continuous along the mucosal surface and tends to begin in the rectum. The mucosa becomes eroded, as in this photograph, which shows only remaining islands of mucosa called "pseudopolyps".

58. At higher magnification, the pseudopolyps can be seen clearly as raised red islands of inflamed mucosa.

59. Pseudopolyps are seen here in a case of severe ulcerative colitis
Pseudopolyps are seen here in a case of severe ulcerative colitis. The remaining mucosa has been ulcerated away and is hyperemic.

60. Crypt abscesses are a histologic finding more typical with ulcerative colitis.

61. Over time, there is a risk for adenocarcinoma with ulcerative colitis
Over time, there is a risk for adenocarcinoma with ulcerative colitis. Here, more normal glands are seen at the left, but the glands at the right demonstrate dysplasia, the first indication that there is a move towards neoplasia.

62. Colon

63. This is normal colonic mucosa
This is normal colonic mucosa. Note the crypts that are lined by numerous goblet cells. In the submucosa is a lymphoid nodule. The gut-associated lymphoid tissue as a unit represents the largest lymphoid organ of the body.

64. A small adenomatous polyp) tubular adenoma ( is seen here
A small adenomatous polyp) tubular adenoma ( is seen here. This lesion is called a "tubular adenoma" because of the rounded nature of the neoplastic glands that form it. It has smooth surfaces and is discreet. Such lesions are common in adults. Small ones are virtually always benign. Those larger than 2 cm carry a much greater risk for development of a carcinoma.

65. This small adenomatous polyp (tubular adenoma) on a small stalk is seen microscopically to have more crowded, disorganized glands than the normal underlying colonic mucosa. Goblet cells are less numerous and the cells lining the glands of the polyp have hyperchromatic nuclei. However, it is still well-differentiated and circumscribed, without invasion of the stalk, and is benign.

66. This adenomatous polyp has a hemorrhagic surface and a long narrow stalk. The size of this polyp--above 2 cm--makes the possibility of malignancy more likely, but this polyp proved to be benign.

67. Here are multiple adenomatous polyps of the cecum
Here are multiple adenomatous polyps of the cecum. A small portion of terminal ileum appears at the right.

68. This is familial polyposis in which the mucosal surface of the colon is essentially a carpet of small adenomatous polyps. Of course, even though they are small now, there is a 100% risk over time for development of adenocarcinoma, so a total colectomy is done, generally before age 20.

69. The gross appearance of a villous adenoma is shown above the surface at the left, and in cross section at the right. Note that this type of adenoma is sessile, rather than pedunculated, and larger than a tubular adenoma (adenomatous polyp). A villous adenoma averages several centimeters in diameter, and may be up to 10 cm.

70. An encircling adenocarcinoma of the rectosigmoid region is seen here
An encircling adenocarcinoma of the rectosigmoid region is seen here. There is a heaped up margin of tumor at each side with a central area of ulceration. Normal mucosa appears at the right. The tumor encircles the colon and infiltrates into the wall.

71. Microscopically, a moderately differentiated adenocarcinoma of colon is seen here. There is still a glandular configuration, but the glands are irregular and very crowded.

72. At high magnification, the neoplastic glands of adenocarcinoma have crowded nuclei with hyperchromatism and pleomorphism. No normal goblet cells are seen.