Myxofibrosarcoma

Symptoms and causes

Myxofibrosarcoma is a type of cancer that begins in the connective tissue. It tends to happen in the arms and legs.

Myxofibrosarcoma starts as a growth of cells that can grow into healthy body tissue. Myxofibrosarcoma might cause a lump under the skin that grows slowly. It often isn't painful. This cancer happens most often in older adults.

Myxofibrosarcoma is a type of soft tissue sarcoma. Soft tissue sarcomas are cancers that happen in the soft tissues that connect, support and surround other body structures.

Symptoms of myxofibrosarcoma include:

• A painless lump on an arm or leg.
• A lump that grows slowly.

Myxofibrosarcoma most often starts in the leg. It rarely starts in the abdomen, where other kinds of sarcomas tend to grow.

The cause of myxofibrosarcoma often isn't known. This cancer starts as a growth of cells in the connective tissue.

Myxofibrosarcoma happens when cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time.

In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to grow and multiply quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells. The cancer cells can form a lump that may grow into healthy body tissue.

The risk of myxofibrosarcoma is higher in adults. This cancer happens most often in adults ages 50 to 70. It is rare in people under age 30.

There is no way to prevent myxofibrosarcoma.