Fibromatosis

Introduction

Fibromatosis is a rare but significant group of conditions characterized by the abnormal growth of fibrous tissue in the body. Unlike cancer, fibromatosis does not spread to distant organs, but it can behave aggressively in the local tissues where it arises. The condition is often considered intermediate between benign and malignant tumors, since it can invade nearby muscles, tendons, and organs, causing pain, restricted movement, and functional problems (1). Fibromatosis can occur in almost any part of the body but is commonly seen in the abdominal wall, extremities, head and neck region, or within the mesentery (the tissue that supports the intestines).

Understanding fibromatosis is crucial because it is not only a medical challenge due to its recurrent nature but also has significant implications for quality of life (1). With appropriate diagnosis and management, patients can lead relatively normal lives, although long-term follow-up is usually required.

Symptoms

The symptoms of fibromatosis vary depending on the location and size of the growth. In many cases, the tumor is painless at first but can cause discomfort as it enlarges. Common symptoms include:

• Palpable mass: A firm, often painless lump under the skin or within muscle tissues.
• Pain or tenderness: Pain may develop if the tumor presses on surrounding nerves or structures.
• Restricted movement: Growth near joints, muscles, or tendons may limit flexibility or mobility.
• Swelling or deformity: The affected area may appear swollen or misshapen.
• Digestive problems: In cases where fibromatosis occurs inside the abdomen, symptoms may include bloating, nausea, or obstruction of the intestines.

Because fibromatosis grows slowly, symptoms may develop over months or even years before patients seek medical attention (2).

Causes

The exact cause of fibromatosis is not fully understood. However, several biological and genetic factors are thought to play a role:

• Genetic mutations: Alterations in specific genes, particularly mutations in the CTNNB1 gene or the APC gene, are commonly associated with fibromatosis. These mutations affect cell signaling pathways, leading to uncontrolled tissue growth.
• Hormonal influences: Estrogen may stimulate fibromatosis growth, which explains why some cases occur or worsen during pregnancy.
• Trauma or surgery: Previous injuries or surgical scars sometimes act as triggering sites for fibromatosis development.
• Familial predisposition: Individuals with inherited conditions such as familial adenomatous polyposis (FAP) are more likely to develop fibromatosis, especially in the abdominal region (3).

Risk Factors

Certain factors increase the likelihood of developing fibromatosis, including:

• Age: Most cases occur in people between the ages of 20 and 40.
• Gender: Women are slightly more affected than men, possibly due to hormonal influences.
• Genetic conditions: People with FAP or Gardner’s syndrome (a variant of FAP) face a much higher risk.
• History of trauma or surgery: Scarring can act as a trigger point for fibromatosis growth.
• Hormonal changes: Pregnancy or high estrogen levels may increase the risk.

Diagnosis

Diagnosing fibromatosis can be challenging, as the condition often mimics other soft tissue tumors (2). A step-by-step approach is generally followed:

• Physical examination: A healthcare provider assesses the mass, its location, and its impact on movement.
• Imaging tests:
  • MRI (Magnetic Resonance Imaging) is the preferred imaging method as it shows the tumor’s exact size, depth, and relationship with surrounding tissues.
  • CT scans are sometimes used, particularly for intra-abdominal fibromatosis.
• Biopsy: A tissue sample is taken and examined under a microscope to confirm fibromatosis and rule out cancer.
• Genetic testing: In some cases, genetic studies may be done to check for mutations linked with the condition.

Because fibromatosis can resemble sarcoma (a malignant soft tissue tumor), accurate diagnosis by an experienced pathologist is critical (3).

Treatment Options

Treatment depends on the size, location, growth rate, and symptoms of the tumor. Options include:

• Active Surveillance (Watchful Waiting)
  • In many cases, fibromatosis may remain stable or even regress without treatment. Doctors often recommend careful monitoring with regular imaging before pursuing aggressive therapy.
• Surgery
  • Surgical removal was once the standard treatment. However, because fibromatosis has a high recurrence rate (20–50%), surgery is now performed selectively, particularly when the tumor causes significant symptoms or threatens vital structures.
• Radiation Therapy
  • Used in cases where surgery is not possible or if the tumor recurs. It helps control growth but comes with potential long-term side effects.
• Medications
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) may slow tumor growth.
  • Hormonal therapy (e.g., tamoxifen) may help in estrogen-sensitive cases.
  • Targeted therapies such as tyrosine kinase inhibitors (e.g., imatinib, sorafenib) are promising in controlling aggressive or recurrent fibromatosis.
  • Chemotherapy is rarely used but may be considered for rapidly growing or inoperable tumors.
• Physical therapy
  • Helps maintain mobility and function, especially for fibromatosis near joints or muscles.

Treatment decisions are usually made by a multidisciplinary team of oncologists, surgeons, and radiologists to tailor therapy to each patient’s situation.

Living With or Prevention

There is no guaranteed way to prevent fibromatosis, especially since many cases are linked to genetic factors. However, living with the condition involves careful management (3):

• Regular monitoring: Imaging every few months ensures early detection of growth or recurrence.
• Symptom management: Pain control, physical therapy, and lifestyle adjustments help maintain daily functioning.
• Emotional support: Coping with a chronic, recurrent condition can be stressful. Support groups and counseling can provide valuable help.
• Healthy lifestyle: While not a cure, maintaining a balanced diet, reducing stress, and staying physically active can improve overall well-being.

For individuals with familial adenomatous polyposis, genetic counseling and regular medical follow-up are essential, as they are at higher risk for fibromatosis and other tumors.

References

1. Al-Khateeb THH. Mandibular versus Maxillary Desmoplastic Fibroma: A Pooled Analysis of World Literature and Report of a New Case. Eur J Dent. 2025 Jul;19(3):595-606. doi: 10.1055/s-0044-1801277. Epub 2025 Mar 12. PMID: 40074000; PMCID: PMC12182419.
2. Hwang JT, Yoon KJ, Park CH, Choi JH, Park HJ, Park YS, Lee YT. Follow-up of clinical and sonographic features after extracorporeal shock wave therapy in painful plantar fibromatosis. PLoS One. 2020 Aug 10;15(8):e0237447. doi: 10.1371/journal.pone.0237447. PMID: 32776988; PMCID: PMC7416956.
3. Taher LY, Saleem M, Velagapudi S, Dababo A. Fibromatosis arising in association with neuromuscular hamartoma of the mandible. Head Neck Pathol. 2013 Sep;7(3):280-4. doi: 10.1007/s12105-012-0418-8. Epub 2013 Jan 12. PMID: 23315379; PMCID: PMC3738757.