Gastrointestinal: Peritoneal Cavity

Question 1

What are the two components of the peritoneal cavity?

Answer 1

• Greater sac
• Lesser sac (behind the stomach)

Question 2

What is the name of the opening between the greater and lesser sacs of the peritoneal cavity?

Answer 2

The epiploic foramen (of Winslow)

Question 3

What is the mental bursa?

Answer 3

Another name for the lesser sac of the peritoneal cavity

Question 4

What are the two sections of the greater sac of the peritoneal cavity?

Answer 4

• Supracolic compartment (above transverse mesocolon)
• Infracolic compartment (below transverse mesocolon)

Note: The right and left paracolic gutters connects these two spaces.

Question 5

Does the peritoneal cavity communicate with the exztraperitoneal pelvis?

Answer 5

Only in women (via the Fallopian tubes)

Question 6

What structure allows direct spread of disease between the stomach, esophagus, and liver?

Answer 6

The gastrohepatic ligament

Question 7

What structure allows direct spread of disease between the stomach and splenic hilum?

Answer 7

The gastrosplenic ligament

Question 8

What structure allows direct spread of disease from the right colon to peri pancreatic/periduodenal lymph nodes?

Answer 8

The duodenocolic ligament

Question 9

Which peritoneal ligaments classically allow direct spread of diseases between intraperitoneal organs?

Answer 9

• Gastrohepatic ligament
• Gastrosplenic ligament
• Duodenocolic ligament

Question 10

What are the major routes by which disease can spread through the abdomen and pelvis?

Answer 10

• Hematogenous
• Lymphatic extension
• Direct invasion (e.g. along ligaments)
• Intraperitoneal seeding (i.e. via peritoneal fluid)

Question 11

What is the natural flow of peritoneal fluid?

Answer 11

From the pelvis to the upper abdomen via the right paracolic gutter (and less so by the left parabolic gutter)

Question 12

Where are serosal-based metastases most commonly found in the setting of peritoneal carcinomatosis?

Answer 12

Places where peritoneal fluid tends to pool or slow down:

• Pouch of Douglas
• Sigmoid mesocolon
• Lower recess of mesentery
• Right paracolic gutter

Question 13

What are the most common locations for intraperitoneal abscesses to collect?

Answer 13

Dependent areas:

• Right posterior subphrenic recess
• Anterior subhepatic space
• Hepatorenal recess
• Pelvic cavity

Question 14

Pseudomyxoma peritonei

Answer 14

A gelatinous ascites that results from either a ruptured mucocele (e.g. appendiceal) or intraperitoneal spread of a mucinous neoplasm (e.g. ovarian/colonic)

Question 15

Answer 15

Pseudomyxoma peritonei

Note: Ascites with scalloped appearance of the liver.

Question 16

What is the most common area for implants in peritoneal carcinomatosis?

Answer 16

The retrovesical space (rectouterine pouch in females and rectovesical pouch in males)

Note: This is the most dependent location in the peritoneal cavity.

Question 17

Answer 17

Omental caking (thickening of the omentum due to metastatic disease)

Note: Usually causes posterior displacement of the bowel from the anterior abdominal wall.

Question 18

Most common locations for mesothelioma

Answer 18

• Pleura (75%)
• Peritoneum (25%)

Question 19

How long after asbestos exposure does peritoneal mesothelioma usually appear?

Answer 19

30-40 years

Question 20

What are the two major types of peritoneal mesothelioma?

Answer 20

• Primary peritoneal mesothelioma (secondary to asbestos exposure)
• Cystic peritoneal mesothelioma (usually young women with no exposure to asbestos)

Question 21

What is the result of barium leaking into the peritoneal cavity?

Answer 21

Barium peritonitis (massive inflammatory reaction with development of ascites and possibly hypovolemic shock)

Note: Long term sequelae result from granuloma/adhesion formation leading to bowel obstructions later on).

Question 22

Treatment for barium peritonitis

Answer 22

IV fluids (to minimize risk of hypovolemic shock due to massive ascites)

Question 23

Barium intravasation

Answer 23

When PO/PR barium contrast ends up in systemic circulation, resulting in pulmonary embolism that is fatal in 50% of cases

Question 24

Risk factors for barium intravasation

Answer 24

Altered bowel mucosa:

• Inflammatory bowel disease
• Diverticulitis

Question 25

Unilocular cystic mass at a mesenteric surgical site…

Answer 25

Think lymphocele

Question 26

Unilocular cystic mass in the mesentery…

Answer 26

• Duplication cyst (if associated with bowel)
• Lymphocele (if at a surgical site)
• Pseudocyst (if history of pancreatitis)

Question 27

Multilocular cystic mass in the mesentery…

Answer 27

Think lymphangioma

Question 28

Differential for many solid mesenteric masses

Answer 28

• Metastases
• Lymphoma
• Mesothelioma

Question 29

Fat-containing solid mass in the mesentery…

Answer 29

Think liposarcoma

Question 30

Differential for a solid mesenteric mass with smooth margins and no fat

Answer 30

• GIST
• Solitary fibrous tumor

Question 31

Differential for a solid mesenteric mass with infiltrative margins and no fat

Answer 31

• Carcinoid (arterial enhancement)
• Desmoid (delayed hyperenhancement)
• Sclerosing mesenteritis (delayed hyperenhancement)

Question 32

Answer 32

Mesenteric lymphoma

Note: This is the “sandwich sign” where there is a lobulated confluent soft tissue mass encasing the mesenteric vessels, “sandwiching” them.

Question 33

Mesenteric lymphoma is usually Hodgkins/non-Hodgkins

Answer 33

Non-Hodgkins

Question 34

Answer 34

Misty mesentery, think mesenteric panniculitis or lymphoma

Note: Most should get a 6 month follow up to establish stability.

Question 35

What characteristics should make you think that a misty mesentery is due to lymphoma rather than mesenteric panniculitis?

Answer 35

• Retroperitoneal lymphadenopathy
• Bulky soft tissue mass “sandwiching” the mesenteric vessels