What are fibrous tumors?

Fibrous tumors are abnormal growths that originate from fibrous (connective) tissue, which supports and connects various parts of the body. These tumors can range from benign (non-cancerous) to malignant (cancerous), and they may develop in the skin, muscles, bones, or internal organs.

Fibrous tumors are relatively rare and may behave very differently depending on their type, location, and growth pattern.

What types of fibrous tumors are there?

Fibrous tumors can be broadly categorized as:

Benign fibrous tumors

• Fibroma: A common benign tumor made up of fibrous tissue. It’s usually slow-growing and painless.
• Desmoid tumors (aggressive fibromatosis): Technically benign but can grow aggressively and invade surrounding tissue.
• Dermatofibroma: A harmless skin growth, often appearing as a firm bump.

Malignant fibrous tumors

• Fibrosarcoma: A rare cancerous tumor that originates in fibrous tissue and can spread to other parts of the body.
• Undifferentiated pleomorphic sarcoma (UPS): Previously known as malignant fibrous histiocytoma (MFH), a type of soft tissue sarcoma with aggressive behavior.

What causes fibrous tumors?

The exact cause isn’t always known, but contributing factors may include:

• Genetic mutations or inherited syndromes (e.g., familial adenomatous polyposis in desmoid tumors)
• Previous injury or trauma to the area
• Radiation exposure (especially for fibrosarcoma)
• Hormonal influence, especially estrogen, in some desmoid tumors

Most benign tumors occur spontaneously without a clear cause.

What are the symptoms of fibrous tumors?

Symptoms vary based on the tumor’s type, size, and location:

• A lump or mass under the skin or in deeper tissues
• Pain or tenderness if the tumor presses on nerves or muscles
• Restricted movement or joint stiffness
• Swelling in the affected area
• Skin changes (if near the surface)
• In malignant tumors: fatigue, weight loss, or symptoms from metastasis (if cancer spreads)

Many fibrous tumors are painless and go unnoticed until they grow larger.

How are fibrous tumors diagnosed?

Diagnosis usually includes:

• Physical examination
• Imaging studies:
  • X-rays, ultrasound, MRI, or CT scan to evaluate size, depth, and involvement of nearby structures
• Biopsy: A small tissue sample taken and examined under a microscope to determine if it is benign or malignant
• Histopathological testing to confirm tumor type and behavior

How are fibrous tumors treated?

Treatment depends on the type, size, and behavior of the tumor:

For benign tumors:

• Observation: Small, painless tumors may not require treatment
• Surgical removal: Recommended if the tumor causes pain, grows, or affects nearby structures
• Medications: In some desmoid tumors, hormone therapy or anti-inflammatory drugs may help shrink the tumor

For malignant tumors (e.g., fibrosarcoma):

• Surgical excision with clear margins
• Radiation therapy to reduce recurrence
• Chemotherapy, especially if the cancer has spread or is inoperable
• Targeted therapy in certain advanced or recurrent cases

A multidisciplinary approach is often necessary for aggressive or complex tumors.

What is the prognosis for fibrous tumors?

• Benign tumors usually have a good outcome, especially if completely removed
• Desmoid tumors may recur even after surgery, but they don’t spread to distant organs
• Fibrosarcoma and UPS have variable outcomes depending on the stage and how early they’re treated

Regular monitoring is essential, especially for tumors that tend to recur.

Can fibrous tumors be prevented?

There is no guaranteed way to prevent fibrous tumors, but early detection and management improve outcomes. If you have a family history of genetic conditions associated with these tumors, talk to your doctor about genetic counseling or regular screenings.