Are Liposarcomas Common?

Liposarcoma is the most common soft tissue sarcoma in adults and can also be seen in adolescents and children. Liposarcomas are usually large, usually deep, painless, and gradually growing masses, and most commonly occur in the lower limbs (such as the popliteal fossa and the inner thigh), retroperitoneum, perinephrum, mesentery area, and shoulders. The incidence in different parts mainly depends on the subtype of the tumor, including atypical lipoma tumor / highly differentiated liposarcoma, dedifferentiated liposarcoma, myxoid liposarcoma, pleomorphic liposarcoma, and mixed liposarcoma.

Basic Information

English name

liposarcoma

Visiting department

Oncology

Multiple groups

adult

Common locations

Lower extremities, retroperitoneum, perirenal, mesentery area, and shoulders

Common symptoms

Large tumor volume

Causes of liposarcoma

The cause is unknown.

Clinical manifestations of liposarcoma

Liposarcomas are usually large, usually deep, painless, and gradually growing masses, and most commonly occur in the lower limbs (such as the popliteal fossa and the inner thigh), retroperitoneum, perinephrum, mesentery area, and shoulders.

Diagnosis of liposarcoma

Diagnosis is based on clinical manifestations, gross examination, and histopathology. Below we will describe the different types of liposarcoma.

1. Atypical lipomatous tumor / highly differentiated liposarcoma

Often large, well-defined lobulated masses. Under the microscope, ALT / WD liposarcoma is composed of relatively mature hyperplastic adipose tissue. Compared with benign lipoma, the cell size is significantly different. Focal nuclei of adipocytes and deep nuclear staining are helpful for diagnosis. Commonly distributed scattered nuclear deep-stained stromal cells and multinuclear stromal cells. A variable number of mono- or multivesicular adipocytes are visible. Including sclerosing liposarcoma, inflammatory liposarcoma, spindle cell subtypes, and heterologous differentiation can also occur.

2. Dedifferentiated liposarcoma

It is usually a large, multinodular yellow mass with scattered, solid, often grayish brown, nonfat areas. Dedifferentiated areas often have necrosis. The histological feature is the migration of ALT / WD liposarcomas to non-lipid sarcomas (mostly highly malignant). 5% to 10% of dedifferentiated liposarcomas can have heterogeneous differentiation, but have nothing to do with clinical prognosis. The most common is myogenic or osteochondrosarcoma differentiation.

3. Myxoid liposarcoma

A typical MLS is a large, painless mass in the deep soft tissues of the extremities, with well-defined, nodular masses. The low-grade malignants were cut brown and jelly. The highly malignant, circular cell area is white and fleshy. There is often no visible necrosis. Under low magnification, MLS has a leaf-like structure, and the cells around the leaflets are abundant. Consistent round and oval primitive non-fat mesenchymal cells and small signet ring-like adipocytes are mixed, and the stroma is obviously mucus-like, with a rich slender, bud-like, "reticular" capillary network. Interstitial hemorrhage is common. MLS often shows a gradual migration of mucus and cell-rich / round cell areas.

High histological grade, necrosis, and high expression of TP53 suggest poor prognosis.

4. Polymorphic liposarcoma

The swollen material is hard, often nodular, and the section is white to yellow. Most tumors are composed of pleomorphic spindle tumor cells and bundle-shaped spindle-shaped, smaller round cells, which are mixed with multinucleated giant cells and polymorphic multi- vacuolar adipocytes.

Liposarcoma immunophenotype

S100 protein and vimentin are often expressed, and CD34 is scattered and positive.

Liposarcoma treatment

The most important prognostic factor is the tumor site. If the tumor is grown in a location that can be completely resected, the tumor margins will not recur after a clean resection. Tumors that occur in deep tissues have a tendency to relapse multiple times, often resulting in death due to invasive growth or dedifferentiation and metastasis of the tumor that cannot be controlled locally.