Gastrointestinal: Peritoneal Cavity Flashcards
What are the two components of the peritoneal cavity?
- Greater sac
- Lesser sac (behind the stomach)
What is the name of the opening between the greater and lesser sacs of the peritoneal cavity?
The epiploic foramen (of Winslow)
What is the mental bursa?
Another name for the lesser sac of the peritoneal cavity
What are the two sections of the greater sac of the peritoneal cavity?
- Supracolic compartment (above transverse mesocolon)
- Infracolic compartment (below transverse mesocolon)
Note: The right and left paracolic gutters connects these two spaces.
Does the peritoneal cavity communicate with the exztraperitoneal pelvis?
Only in women (via the Fallopian tubes)
What structure allows direct spread of disease between the stomach, esophagus, and liver?
The gastrohepatic ligament
What structure allows direct spread of disease between the stomach and splenic hilum?
The gastrosplenic ligament
What structure allows direct spread of disease from the right colon to peri pancreatic/periduodenal lymph nodes?
The duodenocolic ligament
Which peritoneal ligaments classically allow direct spread of diseases between intraperitoneal organs?
- Gastrohepatic ligament
- Gastrosplenic ligament
- Duodenocolic ligament
What are the major routes by which disease can spread through the abdomen and pelvis?
- Hematogenous
- Lymphatic extension
- Direct invasion (e.g. along ligaments)
- Intraperitoneal seeding (i.e. via peritoneal fluid)
What is the natural flow of peritoneal fluid?
From the pelvis to the upper abdomen via the right paracolic gutter (and less so by the left parabolic gutter)
Where are serosal-based metastases most commonly found in the setting of peritoneal carcinomatosis?
Places where peritoneal fluid tends to pool or slow down:
- Pouch of Douglas
- Sigmoid mesocolon
- Lower recess of mesentery
- Right paracolic gutter
What are the most common locations for intraperitoneal abscesses to collect?
Dependent areas:
- Right posterior subphrenic recess
- Anterior subhepatic space
- Hepatorenal recess
- Pelvic cavity
Pseudomyxoma peritonei
A gelatinous ascites that results from either a ruptured mucocele (e.g. appendiceal) or intraperitoneal spread of a mucinous neoplasm (e.g. ovarian/colonic)
Pseudomyxoma peritonei
Note: Ascites with scalloped appearance of the liver.
What is the most common area for implants in peritoneal carcinomatosis?
The retrovesical space (rectouterine pouch in females and rectovesical pouch in males)
Note: This is the most dependent location in the peritoneal cavity.
Omental caking (thickening of the omentum due to metastatic disease)
Note: Usually causes posterior displacement of the bowel from the anterior abdominal wall.
Most common locations for mesothelioma
- Pleura (75%)
- Peritoneum (25%)
How long after asbestos exposure does peritoneal mesothelioma usually appear?
30-40 years
What are the two major types of peritoneal mesothelioma?
- Primary peritoneal mesothelioma (secondary to asbestos exposure)
- Cystic peritoneal mesothelioma (usually young women with no exposure to asbestos)
What is the result of barium leaking into the peritoneal cavity?
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).
Treatment for barium peritonitis
IV fluids (to minimize risk of hypovolemic shock due to massive ascites)
Barium intravasation
When PO/PR barium contrast ends up in systemic circulation, resulting in pulmonary embolism that is fatal in 50% of cases
Risk factors for barium intravasation
Altered bowel mucosa:
- Inflammatory bowel disease
- Diverticulitis
Unilocular cystic mass at a mesenteric surgical site…
Think lymphocele
Unilocular cystic mass in the mesentery…
- Duplication cyst (if associated with bowel)
- Lymphocele (if at a surgical site)
- Pseudocyst (if history of pancreatitis)
Multilocular cystic mass in the mesentery…
Think lymphangioma
Differential for many solid mesenteric masses
- Metastases
- Lymphoma
- Mesothelioma
Fat-containing solid mass in the mesentery…
Think liposarcoma
Differential for a solid mesenteric mass with smooth margins and no fat
- GIST
- Solitary fibrous tumor
Differential for a solid mesenteric mass with infiltrative margins and no fat
- Carcinoid (arterial enhancement)
- Desmoid (delayed hyperenhancement)
- Sclerosing mesenteritis (delayed hyperenhancement)
Mesenteric lymphoma
Note: This is the “sandwich sign” where there is a lobulated confluent soft tissue mass encasing the mesenteric vessels, “sandwiching” them.
Mesenteric lymphoma is usually Hodgkins/non-Hodgkins
Non-Hodgkins
Misty mesentery, think mesenteric panniculitis or lymphoma
Note: Most should get a 6 month follow up to establish stability.
What characteristics should make you think that a misty mesentery is due to lymphoma rather than mesenteric panniculitis?
- Retroperitoneal lymphadenopathy
- Bulky soft tissue mass “sandwiching” the mesenteric vessels
