Retroperitoneal space

Structures of the retroperitoneal space

Overview of the individual body cavities

The retroperitoneal space or simply the retroperitoneal space ( retroperitoneum ) includes those anatomical structures behind the peritoneum are (peritoneum) and are not enclosed by the peritoneum. "Retroperitoneal" means "behind the peritoneum".

In terms of developmental history, a distinction is made primarily between retroperitoneal and secondary retroperitoneal organs . Those organs that arise behind the abdominal cavity are primarily retroperitoneal. These include the kidneys , adrenal glands, and ureters .

In contrast to this, the secondary retroperitoneal organs arise in the abdominal cavity: They are initially intraperitoneal, and through growth (pressure and tensile forces) these organs are then pressed against the abdominal wall, whereby their shell, the visceral peritoneum, grows together with the parietal peritoneum of the abdominal wall. They therefore no longer have a mesentery and are severely restricted in their mobility compared to the organs located intraperitoneally. The secondary retroperitoneal organs in humans include:

• Pancreas (pancreas)
• Duodenum (duodenum) with the exception of the upper part (pars superior)
• Ascending and descending colon (ascending and descending part of the large intestine)
• Rectum up to the sacral flexure

In domestic animals , these organs, with the exception of parts of the pancreas, are located intraperitoneally, so they have a mesentery.

In addition to the retroperitoneal organs, in the median plane of the retroperitoneal space are the large axial ducts:

• Abdominal part ( pars abdominalis ) of the aorta (large body artery )
• Inferior vena cava (lower vena cava)
• Vena lumbalis ascendens (lumbar vein)
• Truncus sympathicus ( trunk ganglia)
• Cisterna chyli (lumbar cistern, a collecting space for lymph)

Tumors

Since the retroperitoneal space consists of loose connective tissue and fat, it allows tumor growth of considerable size before it is noticeable. For this reason, tumors in the retroperitoneal space are discovered accidentally, or often only very late, through obstruction of nerves or vessels, through metastases or, more rarely, through direct tumor invasion. Retroperitoneal malignancies make up only 1% of cancers of the abdomen.

Four types of tumors in particular are common:

1. Soft tissue sarcomas make up about 80% of malignant retroperitoneal tumors . The most common is liposarcoma , as well as leiomyosarcoma and malignant fibrous histiocytoma
2. neurogenic tumors are more often benign. These include neuroendocrine tumors such as the extraadrenal pheochromocytoma , as well as the ganglioneuroma based on the sympathetic nerve plexus or the paraganglioma .
3. Germ cell tumors that occur particularly in young men between 15 and 35 years of age and are often associated with elevated levels of the tumor markers alpha-1-fetoprotein and beta-HCG .
4. Lymphomas with benign or malignant lymphoproliferative tumors

Web links

Commons : retroperitoneal space  - album with pictures, videos and audio files

Individual evidence

1. ↑ Michael L. Blute, Jeremy S. Abramson, Kevin C. Cronin, Valentina Nardi: Case 5-2017: A 19-year-old man with hematuria and a retroperitoneal mass. New England Journal of Medicine 2017, Volume 376, Issue 7 February 16, 2017, pages 684-692, doi: 10.1056 / NEJMcpc1610100 .