Soft (also known as connective) tissue consists of muscle, ligaments, cartilage, tendons, fat cells, and the lining of blood vessels. A malignant (cancerous) tumor of this type of tissue is known as a sarcoma. Primary bone cancer (that originates in the bone) is also known as sarcoma; some forms of sarcoma affect both soft tissue and bone.
Overall, soft tissue and bone sarcomas are very rare and make up roughly one percent of all cancer diagnoses in the United States. There are anywhere from 50 to 70 subtypes, some that are more common in children and others that almost exclusively affect adults over the age of 60.
Because bone and soft tissues are located throughout the body, sarcomas can technically develop anywhere in the body, however, they tend to be most common in the long bones of the legs and arms, especially during the growth spurts of childhood and early adolescence. This makes limb preservation a central focus of treatment for Los Angeles orthopedic oncology surgeons.
Common Subtypes of Malignant Soft Tissue Tumors
Liposarcomas – Liposarcomas develop in fat tissue, most commonly in the thigh or abdominal cavity (retroperitoneum). They are one of the more common types of soft tissue tumors, although like all sarcomas they are rare compared to other forms of cancer. They are most common in adult patients over the age of 40. Liposarcomas are further broken down and categorized according to the tumor’s composition and cell behavior when examined under a microscope:
- Well differentiated (most common)
- Myxoid/round cell
- Dedifferentiated (least common)
Leiomyosarcoma – The third most common type of malignant soft tissue tumors, leiomyosarcomas develop in the smooth, involuntary muscles of the body. Involuntary muscles are the ones you can’t control by thinking or forcing a movement like a bicep or tricep. Smooth muscle includes:
- Vascular (lining of blood and lymphatic vessels, veins, and arteries)
- Uterine lining (uterus)
- Reproductive tract (male and female)
- GI (gastrointestinal tract)
- Respiratory tract
- Iris (eye)
Invasive Skin Cancers – Most people are familiar with the most common type of skin cancer – melanoma. Not only does melanoma account for most skin cancer diagnoses, it is also the most common form of all cancers. Skin cancer alone accounts for more cases than the following three most common forms of cancer combined – breast, colon, and prostate.
Just as the skin has several layers, different forms of skin cancer affect the various layers. As many as a million Americans are diagnosed with some form of skin cancer every year.
The three main forms of skin cancer are:
- Basal cell carcinoma
- Squamous cell carcinoma
There are also rarer types of skin cancer like Merkel cell tumors, and dermatofibrosarcoma protuberans.
Dermatofibrosarcoma protuberans (DFSP) is an extremely rare type of malignant soft tissue tumors that develops in the dermis layer of the skin. It can develop anywhere including the arms, legs, head, and neck but is most commonly diagnosed in the torso. Although it has a high risk of localized recurrence, the risk of metastasis is generally low.
Other common types of malignant sarcoma include:
- Clear cell sarcoma
- Undifferentiated pleomorphic sarcoma (formerly known as malignant fibrous histiocytoma)
- Epithelioid sarcoma
- Low grade fibromyxoid sarcoma
- Synovial sarcoma
- Adult fibrosarcoma
- Peripheral nerve sheath tumors (neurogenic sarcomas, neurofibrosarcomas, malignant schwannomas)
- Alveolar soft part sarcoma
- Low-grade myxofibrosarcoma
- Gastrointestinal stromal tumor (GIST)
- Kaposi sarcoma
- Desmoplastic small round cell tumor
- Angiosarcoma (hemangiosarcoma/lympangiosarcoma)
Connective Tissue Sarcoma Diagnosis and Treatment in Los Angeles
Soft tissue tumors are assigned a grade and stage at diagnosis to help determine how aggressive it is, whether it is fast or slow moving, the likelihood of metastasis (spread to the lymph nodes and other organs and tissue), size, and other characteristics that then help to determine the most appropriate and effective form of treatment.
Some soft tissue tumors can be removed with surgery, while others may be treated with chemotherapy, radiation therapy, or medication. In many cases, a combination of surgery and chemo or radiation treatment will be necessary. Because connective tissue and bone are found throughout the body, sarcomas can technically develop anywhere, but they are most commonly diagnosed in the bones of the arms and legs (tibia, ulna, radius, fibula, femur, humerus).
This makes limb preservation a priority in treatment, especially in children and young adolescents (although rare, bone sarcomas are one of the most common forms of childhood cancer). Learn more about soft tissue tumors at cancer.gov.
Find an Orthopedic Oncologist in Los Angeles
Daniel C. Allison, MD, FACS, MBA, board certified in orthopedic surgery, specializes in orthopedic oncology and limb preservation, advanced joint reconstruction (anterior hip replacement), and treatment of musculoskeletal injuries and disorders. Dr. Allison is the Assistant Director of Orthopedic Oncology in Cedars-Sinai Sam Oschin Cancer Center in Los Angeles. For more information on the signs, symptoms, and risks for soft tissue and bone sarcomas and diagnosis and treatment, contact Dr. Allison’s office by calling (310) 730-8008.