Definition:
Peritoneal Carcinosis is defined as seeding and implantation of neoplastic cells into peritoneal cavity and may represents the advanced evolutive stage of every tumors developed into abdominal and pelvic organs.
However ovarian,
stomach and colorectal cancers accounts for almost all case 1-2.
Furthermore,
there are also tumors,
even though rare,
that develop directly from peritoneum (mesothelioma) or extraperitoneal organs (breast cancer).
When the disease increases,
the tumoral cells reach and affect the membrane covering the same organs (visceral peritoneum).
Once this “barrier” has been passed,
the affected cells are able to move into the abdominal cavity,
carried by the peritoneal fluid.
These cells tend to accumulate in those points of greater liquid readsorption,
creating agglomerates that grow more and more,
spreading into the whole abdomen and originating the carcinosis.
Peritoneal metastases spread
When neoplastic cells reach peritoneal cavity,
they continue to spread in four possible routes 3-5:
(1) Direct spread along peritoneal ligaments,
mesenteries and omenta to non-contiguous organs;
(2) Intraperitoneal seeding via ascitic fluid;
(3) Lymphatic extension;
(4) Embolic haematogenous spread.
Fig. 1
Intraperitoneal seeding via ascitic fluid is one of the most important way of peritoneal metastases spreading and the main cause of peritoneal carcinomatosis.
Peritoneal fluid circulation
The peritoneal cavity is subdivided by peritoneal reflections and mesenteric attachments into several compartments and recesses that are anatomically continues,
either directly or indirectly 3-5.
Fig. 2: Peritoneal cavity is subdivided into several spaces and recesses by peritoneal reflections and mesenteric insertions.
Fig. 3: Force of gravity drives pool of peritoneal fluid preferentially in pelvic cavity. In particular, from the
left infracolic space, flow is direct along the superior plane of sigmoid mesocolon and than along
the right side of the rectum. From the right infracolic space spread occurs along the small bowel
mesentery. The cul-de-sac is first filled and then, symmetrically, the lateral paravesical recesses.
From the pelvis peritoneal fluid is able to flow upward due to the pressure gradient created by
diaphragm during inspiration and peristaltic motion of the intestine. Fluid enters the paracolic
gutters and then moves into the right subhepatic and right subphrenic regions. The left paracolic
gutter is shallow and is limited superiorly by the phrenicocolic ligament, which extends from the
splenic flexure of the colon to the diaphragm. Consequently, the majority of fluid flows into the
right paracolic gutter.