Soft tissue sarcomas of the abdomen and pelvis include a wide spectrum of histological subtypes with both low and high-grade tumors.
Sarcomas in the abdominal region are often grouped according to localization:
- Abdominal wall
A retroperitoneal tumor is localized behind the dorsal layer of the peritoneum from the diaphragm and down to the pelvic floor.
The most common sarcomas in this region comprise the histological subtypes liposarcoma and leiomyosarcoma. Other histological subtypes include pleomorphic sarcoma, malignant fibrous histiocytoma (MFH), fibrosarcoma, solitary fibrous tumor, malignant peripheral nerve sheath tumor, and others.
Intra-abdominal sarcomas are also referred to as visceral sarcomas and may involve any of the visceral organs within the abdominal cavity, the most common of which is the gastrointestinal tract. The most common histological subtypes include gastrointestinal stromal tumor (GIST) and leiomyosarcoma.
GIST may occur anywhere in the gastrointestinal tract, from the esophagus to the anus. In rare cases, they can occur outside the gastrointestinal tract, for example the greater omentum or retroperitoneum.
The most common gynecological sarcomas occur in the uterus and comprise the histological subtypes leiomyosarcoma and endometrial stromal sarcoma. Other types of soft tissue sarcomas, in combination with adenomatous (adenosarcoma) or carcinomatous components (carsinosarcoma), can occur.
Abdominal wall sarcomas
Soft tissue sarcomas of the anterior abdominal wall include such histological subtypes as liposarcoma, synovial sarcoma, fibrosarcoma, dermatofibrosarcoma protuberans (DFSP) and others.
In 2015, two persons were diagnosed with soft tissue sarcomas in the abdomen and pelvis, both were men. Soft tissue sarcomas in the abdomen and pelvis constitute 25-30% of all soft tissue sarcomas.
Retroperitoneal sarcomas amount to about 15% of all soft tissue sarcomas, while intra-abdominal sarcomas account for 10-15%. They occur in all age groups and involve men and women equally.
Gynecological sarcomas may occur in women of all ages and comprise about 5% of all uterine cancer. Among these, leiomyosarcoma amounts to about 60%, while endometrial stromal sarcoma and adenosarcoma, comprise 20% and 6%, respectively.