Retroperitoneal liposarcoma

Case contributed by Fabio Macori


Abdominal pain. US (not available) showed a large mass arising out of the pelvis.

Patient Data

Age: 45 years
Gender: Female

There is a large encapsulated mass measuring approximately 32 cm by 27 cm by 25 cm in craniocaudal, transverse and AP diameter extending from the level of the fundus of the stomach to the dome of the urinary bladder. The lesion is of fat density with diffuse groundglass opacity, multiple intemal septations and sparse punctate calcifications. It is intimater related to the anterior and lateral aspect of the left kidney and displaces small bowel and colon. No enlarged abdominal, retroperitoneal, pelvic or intrathoracic modes.

There is a 4.4 cm left adrenal mass, solitary 2.7 cm segment 6 hepatic hypodensity and a 6 mm left basal pulmonary module.

Bulky fibroid uterus with IUD in position. Normal ovaries and adnexa. No ascites


Large encapsulated mass, imaging characteristics are consistent with a liposarcoma. The left adrenal and hepatic lesions are likely metastatic. 6 mm left basal pulmonary nodule is indeterminate and may also be a metastasis.

Case Discussion

Retroperitoneal sarcomas are rare tumors and represent about 10-15% of soft tissue sarcomas (that is to say, only 1% of all tumors). Often these are large lesions, on average 10 cm in size, but which can reach considerable dimensions, even to occupy the entire abdomen. The most common forms of retroperitoneum sarcomas are well-differentiated liposarcoma, dedifferentiated liposarcoma, leiomyosarcoma and solitary fibrous tumor. A particular presentation, less rare than previously thought, is constituted by leiomyosarcoma originating from the large retroperitoneal veins (e.g. leiomyosarcoma of the vena cava).

The complete excision surgical treatment represents the standard treatment, and in retroperitoneum sarcomas, in particular, the quality of initial surgery is correlated with long-term survival.
The greatest risk for this type of disease is represented by local recurrence, while the relapse event with distant metastases is less frequent. For the particular anatomical site of origin (retroperitoneal space is located in the abdomen behind the viscera), it is often technically challenging to obtain a surgical resection with wide safety margins.

This patient underwent surgical excision. The histology was a low-grade retroperitoneal liposarcoma.

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