Liposarcoma is a malignant

Malignant

Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...

 tumor

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

 that arises in fat cells

Adipose tissue

In histology, adipose tissue or body fat or fat depot or just fat is loose connective tissue composed of adipocytes. It is technically composed of roughly only 80% fat; fat in its solitary state exists in the liver and muscles. Adipose tissue is derived from lipoblasts...

 in deep soft tissue

Soft tissue

In anatomy, the term soft tissue refers to tissues that connect, support, or surround other structures and organs of the body, not being bone. Soft tissue includes tendons, ligaments, fascia, skin, fibrous tissues, fat, and synovial membranes , and muscles, nerves and blood vessels .It is sometimes...

, such as that inside the thigh or in the retroperitoneum

Retroperitoneum

The retroperitoneal space is the anatomical space in the abdominal cavity behind the peritoneum. It has no specific delineating anatomical structures...

.

They are typically large bulky tumors which tend to have multiple smaller satellites extending beyond the main confines of the tumor.

Liposarcomas, like all sarcoma

Sarcoma

A sarcoma is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm. Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues...

s, are rare.

Symptoms

Patients usually note a deep seated mass in their soft tissue. Only when the tumor is very large do symptoms of pain or functional disturbances occur.

Retroperitoneal tumors may present themselves with signs of weight loss

Weight loss

Weight loss, in the context of medicine, health or physical fitness, is a reduction of the total body mass, due to a mean loss of fluid, body fat or adipose tissue and/or lean mass, namely bone mineral deposits, muscle, tendon and other connective tissue...

 and emaciation

Emaciation

Emaciation occurs when an organism loses substantial amounts of much needed fat and often muscle tissue, making that organism look extremely thin. The cause of emaciation is a lack of nutrients, starvation, or disease....

 and abdominal pain

Abdominal pain

Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...

. These tumors may also compress the kidney or ureter leading to kidney failure.

Diagnosis

The diagnosis is established by histologic examination of the tissue, i.e. biopsy

Biopsy

A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

 or excisional biopsy. Lipoblasts are often present; these are cells with an abundant clear multi-vacuolated

Vacuole

A vacuole is a membrane-bound organelle which is present in all plant and fungal cells and some protist, animal and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain...

 cytoplasm

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 and an eccentric darkly staining nucleus that is indented by the vacuoles.

Subtypes

Several subtypes of liposarcoma exist:

• Well-differentiated liposarcoma, synonymous with atypical lipomatous tumor; the former term is used almost exclusively for lesions in the retroperitoneum
  Retroperitoneum
  The retroperitoneal space is the anatomical space in the abdominal cavity behind the peritoneum. It has no specific delineating anatomical structures...
  
  , while the latter is used for lesions arising elsewhere.
• Dedifferentiated liposarcoma, which consists of well-differentiated liposarcoma adjacent to a more poorly differentiated tumor.
• Myxoid/round cell liposarcoma.
• Pleomorphic liposarcoma.

Incidence and prevalence

Most frequent in middle-aged and older adults (age 40 and above), liposarcomas are the second most common of all soft-tissue sarcoma

Sarcoma

A sarcoma is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm. Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues...

s following malignant fibrous histiocytoma

Malignant fibrous histiocytoma

Pleomorphic undifferentiated sarcoma , also undifferentiated pleomorphic sarcoma and previously malignant fibrous histiocytoma , is a type of soft tissue sarcoma....

s. Annually 2.5 cases occur per million population.

Prognosis

The prognosis varies depending on the site of origin, the type of cancer cell, the tumor size, the depth, and proximity to lymph nodes. Well-differentiated liposarcomas treated with surgery and radiation have a low recurrence rate (about 10%) and rarely metastasize. Five-year survival rates vary from 100% to 39% based on histological subtype.

External links

• humpath #2495 (Pathology images)
• Information from The Doctor's Doctor website
• Liposarcoma in the Sarcoma Learning Center