| • The opened colon shows the dilated openings(white arrow) of
several diverticuli
• The wall(green arrow) is not thickened and the pericolic fat show no evidence of inflammation |
| • The opened colon shows the dilated openings(white arrow) of
several diverticuli
• The wall(green arrow) is not thickened and the pericolic fat show no evidence of inflammation |
| Diverticular Disease |
| Etiology |
•Increased intraluminal colonic pressure •Congenital weakness of colon wall at points of entrance of nutrient
arteries •Acquired weakness of colon wall as with increased elastin formation with
age, or connective tissue abnormalities associated with diseases such as
Marfan^s or Scleroderma |
| Pathogenesis |
•Chronic or recurrent increase in intraluminal colonic pressure causes
herniation of the mucosa through the colon wall in an area of potential
weakness where the penetrating nutrient arteries enter the muscularis
propria |
| Epidemiology |
•A disease of the U.S. and other developed
countries where processed food has replaced cereal fiber •A disease of the population above age 40, increasing with age •Diverticulosis in the younger population is often associated with
connective tissue disorders •The incidence of diverticulosis is increasing in Western countries and in
populations with a change to processed food |
| Clinical |
•While the prevalence of diverticulosis is high, only 20% of afflicted
people are ever symptomatic •The most common symptom is colicky left lower quadrant pain thought to be
due to acute increase in intraluminal pressure •The most common complication is diverticulitis which is accompanied by left
lower pain, fever and often tenderness. Presence of a palpable mass
indicates abscess formation. Other bowel symptoms are usually present but
are variable •Minor blood loss commonly occurs in diverticular disease, but severe acute
blood loss occurs in 3-5% of afflicted people. It is the most common cause
of massive lower GI hemorrhage •Recurrent episodes of diverticulitis may lead to extensive focal scarring
and signs of obstruction •Most people with diverticulosis are asymptomatic or have mild disease and
overall only 1% will require hospitalization |
| General Gross Description |
•Diverticuli are most common in the sigmoid colon, but may be found along
the entire length of the colon. They are concentrated along the course of
the Taenia Coli •On the serosal surface, non-inflamed diverticuli (diverticulosis) appear as
small saccular protuberances less than 1.0cm with thin compressible walls if
empty of fecal contents or firm is filled with fecal matter •Their color is the same as the serosa of the adjoining bowel •Transverse section of the diverticular sacs will reveal a thin wall with
the lumen being empty or containing fecal matter which may be soft or quite
desiccated and firm. A fortunate cut will demonstrate a thin tract leading
from the sac to the lumen of the colon where the adjoining mucosa will
appear entirely normal •The mucosa is usually studded with small(<2mm) openings to numerous
diverticuli •When inflamed(diverticulitis), they are most commonly seen at the stage of
diverticular abscess formation •The serosal surface is erythematous, may contain exudate over the region of
abscess formation, and the pericolic fat is firm •Transverse section will usually reveal an area of necrotic tissue or a
pocket of pus, with the surrounding tissue being firm secondary to
organization •The mucosa is generally normal with openings to numerous non inflamed
diverticuli noted |
| General Micro Description |
•Diverticuli are acquired protrusions of the mucosa through the colonic
wall and contain a lining of normal colonic mucosa which may be compressed
by inspissated fecal matter, an attenuated muscularis mucosa and submucosa.
Muscularis propria is never seen •A thin track lined by normal colonic mucosa leads from the sac to the lumen
where normal colonic mucosa is seen •Inflamed diverticuli contain inspissated fecal material and begin with
accumulation of polys followed by necrosis of the mucosal lining. When
symptomatic the inflammation has spread into the serosa and pericolic
tissue, and when seen surgically a diverticular abscess has usually
formed •When removed surgically we usually see fibroblastic organization of the
pericolic tissue •If the colon is removed because of massive bleeding due to diverticular
disease, and you are able to find the involved diverticulum, it is usually
not inflamed and partially destroyed by the hemorrhage |
| Reference |
• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 806-808 • Sleisenger MH, Fordtran JS. Gastrointestinal disease. 5th ed. Philadelphia: Saunders, 1993, pp.1347.
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