Uncertain differentiation refers to a group of rare soft tissue sarcomas that do not resemble other sarcoma types or normal cells under a microscope. These types of sarcoma are usually hard to diagnose. They are malignant sarcomas that tend to grow and spread fast to other parts of your body from the primary tumor site.
We treat various subtypes of uncertain differentiation, including undifferentiated pleomorphic sarcoma, a unique high-grade aggressive sarcoma because of its cellular makeup.
At the Sarcoma Oncology Center, we design the most effective course of treatment for our patients. We ensure that they receive proper attention and care from prestigious oncologists who are specialists in sarcoma and its numerous types.
Uncertain differentiation sarcoma is a sarcoma type that shares no common cellular resemblance to other soft tissue sarcomas. It represents approximately 20% of all soft tissue sarcomas.
Differentiation means how different the sarcoma cells look under a microscope compared to normal cells. It is used in tumor grading systems, which are different for each type of cancer. Well-differentiated tumor cells look more like normal cells and tend to grow and spread more slowly than poorly differentiated or undifferentiated cancer cells.
For the most part, surgery tends to be the best option for these types of sarcomas. It may also be combined with other treatment methods.
Uncertain differentiation sarcoma has various subtypes that are characterized according to their appearance.
Undifferentiated pleomorphic sarcoma, formerly called malignant fibrous histiocytoma or MFH cancer, is a high-grade aggressive sarcoma that typically occurs in the arms or legs. In rare cases, it can occur in the area behind the abdominal organs, called the retroperitoneum. MFH cancer may also occur in a part of the body where a patient previously received radiation therapy.
The name comes from the way the tumor cells appear under the microscope. Undifferentiated means the tumor cells lack any clear resemblance to normal cells and it is difficult to tell where in the body they originated from their appearance. Pleomorphic indicates that the tumor cells grow in multiple shapes and sizes without following the regular pattern of a normal cell.
Undifferentiated pleomorphic sarcoma is a malignant sarcoma that grows quickly and spreads to other parts of the body, including the lungs. It usually occurs in older adults and may sometimes occur as a second sarcoma in patients who have retinoblastoma, a kind of eye cancer that starts in the retina.
Epithelioid sarcoma usually develops under the skin of the hands, forearms, feet, or lower legs. It often spreads to other body parts in the early stage of the tumor.
Epithelioid sarcoma causes firm growth under the skin, which is called a nodule. Sometimes, the growths may cause sores on the skin that do not heal. It often affects teenagers and young adults but can also affect older people.
Synovial sarcoma is a malignant sarcoma that typically affects the leg, foot, hand, and knee joints. It begins as a growth of cells that multiplies quickly. The first symptom is usually a lump under the skin that may or may not hurt.
In adults, this type of sarcoma is often found as a painless lump in the thigh or buttock. It typically affects men more than women. It can be difficult to diagnose in the early stage because the tumor forms a painless swelling. It can spread to other body parts, including the lungs, chest cavity, liver, and bone.
Clear cell sarcoma is a rare tumor that shares features of both sarcoma and melanoma. It can travel to lymph nodes (typical of melanoma) and to the lung (typical of sarcomas). Although the origin of this cancer is unknown, it often develops in arm or leg tendons.
This type of uncertain differentiation sarcoma is a rare, slow-growing type of sarcoma that forms in soft tissues outside the bone. It may grow big and spread to nearby tissue or other body parts, especially the lungs. Extraskeletal myxoid chondrosarcoma is the second most common primary bone cancer of cartilage cells.
Ewing sarcoma develops in bones and the soft tissue around the bones. It is the third most common primary type of bone cancer. Although it can occur in any bone, this tumor typically begins in the leg bones and the pelvis.
This type of uncertain differentiation sarcoma grows in the abdomen and pelvic areas of the body and tends to spread further to the liver and lungs. This subtype may induce symptoms such as pain, nausea, vomiting, and swelling in the abdomen.
Uncertain differentiation sarcomas likely arise from genetic predisposition and environmental factors. The exact cause of uncertain differentiation is not clear.
Like other subtypes of soft tissue sarcoma, uncertain differentiation may not have noticeable symptoms until it has reached an advanced stage or spread to another part of the body. Therefore, it is critical to pay attention to any abnormal signs and symptoms you may experience to ensure timely treatment for malignant tumors.
Symptoms of uncertain differentiation may include:
Diagnosis of uncertain differentiation sarcoma depends on where the tumor has formed in your body. Your doctor may ask for the following tests:
The treatment for uncertain differentiation sarcoma comprises a personalized multimodal approach. It often combines standard treatments, such as surgery and radiation therapy, with new types of treatment, like clinical trials and targeted therapy.
At Sarcoma Oncology Center, our team collaborates with surgeons, radiologists, and radiation oncologists from prominent institutions to ensure our patients receive personalized attention.
The following treatment options may be considered for treating uncertain differentiation sarcomas.
Uncertain differentiation sarcoma is unlike other types of soft tissue sarcoma. The treatment plan for this type of sarcoma is based on the tumor stage, prior treatments (if any), growth of the tumor, and biopsy analysis.
At our office in Santa Monica, we design personalized and innovative plans for treating skeletal muscle sarcoma.
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