Retroperitoneal mass (R19.0 Swelling, mass, and lump in abdomen and pelvis) refers to an unphysiologic increase in volume of a structure in the retroperitoneum (“lying behind the peritoneum“).
The following structures are retroperitoneal:
- Kidneys
- Adrenal glands
- Ureters (ureters)
- Large ducts
- Pars abdominalis (abdominal portion) of the aorta (large body artery).
- Inferior vena cava (inferior vena cava)
- Vena lumbalis ascendens (lumbar vein)
- Truncus sympathicus (border ganglia).
- Cisterna chyli (lumbar cistern, a collecting space for lymph).
Retroperitoneal masses are solid, cystic, inflammatory, or infectious.
Tumors of the retroperitoneum are malignant (malignant) in about 75% of cases. These include malignant mesenchymal tumors and sarcomas. Furthermore, lymph node metastases/colonization of malignant cancer cells in lymph nodes (e.g. due to testicular, mammary, cervical, endometrial, ovarian, colon, gastric, renal carcinoma) occur.
Benign (benign) tumors in the retroperitoneal space include lipomas, neurogenic tumors (schwannoma, neurofibroma), paragangliomas, fibromatosis, and angiomyolipomas of the kidney.
A peritoneal mass can be a symptom of many diseases (see “Differential diagnoses”).
Course and prognosis: As long as no abdominal complaints are caused, the diagnosis of a peritoneal mass is an incidental finding (usually already of considerable size). To establish the diagnosis, a biopsy (tissue sampling) is performed after imaging diagnosis.Course and prognosis depend on the cause of the retroperitoneal mass.
