Fibroma of tendon sheath is a non-cancerous growth that appears as a small, firm lump. This uncommon condition forms on the tendon sheath, a protective layer surrounding tendons. The World Health Organization reclassified these tumors in 2020 as a specific, benign type within a broad category of soft tissue neoplasms. It is usually painless and does not spread to other parts of the body.
Understanding Fibroma of Tendon Sheath
A tendon sheath is a tube-like membrane that encloses a tendon, providing lubrication and facilitating smooth movement. A fibroma of tendon sheath develops as a benign fibrous tumor within or near this sheath. These tumors are slow-growing, firm to the touch, and usually appear as a single lump.
The precise cause of these fibromas is often unknown, but some cases may be linked to trauma or repetitive motion. The tumors are composed of spindle-shaped cells embedded within a dense, fibrous matrix.
These fibromas most commonly occur in the distal extremities, particularly the hands and fingers. They can also appear on the feet, wrist, and, less frequently, around larger joints like the knee, shoulder, elbow, and ankle. While they can affect individuals of all ages, they are most frequently reported in adults between 20 and 50 years old.
Identifying Signs and Symptoms
A fibroma of tendon sheath presents as a firm, well-defined nodule located under the skin. These lumps are generally small, often less than 2 centimeters in diameter. They are usually round or oval in shape and may feel somewhat mobile beneath the skin.
While often painless, some individuals may experience localized tenderness or mild pain. If the lump grows large or is situated near a joint, it might restrict movement or cause discomfort.
Diagnosis and Treatment Options
Diagnosing a fibroma of tendon sheath begins with a physical examination, where a doctor will palpate the lump to assess its size, firmness, and mobility. Imaging techniques are often used to further characterize the lesion. An ultrasound may show a solid, nodular mass. Magnetic Resonance Imaging (MRI) can reveal a well-defined mass, often showing minimal enhancement.
While imaging can provide valuable information, a definitive diagnosis is established through a biopsy, specifically a histopathological examination of the tissue. This microscopic analysis confirms the presence of bland spindle cells in a dense collagenous stroma, along with characteristic slit-like thin-walled vessels. This step is important to differentiate it from other soft tissue tumors.
The primary and most effective treatment for a fibroma of tendon sheath is surgical excision, which involves removing the entire lesion. This procedure is often performed on an outpatient basis and can be done under local or general anesthesia, depending on the size and location of the fibroma. Surgical removal aims to relieve any symptoms, confirm the diagnosis, and minimize the chance of recurrence. For cases where the fibroma is small, asymptomatic, and not causing any functional issues, observation may be considered as a non-surgical management option.
Outlook and Potential for Recurrence
The prognosis for individuals with a fibroma of tendon sheath after surgical treatment is generally favorable, given its benign nature. Once the fibroma is removed, most patients experience a full recovery with no long-term complications. The tumor does not metastasize, meaning it does not spread to distant parts of the body.
While the outlook is good, there is a possibility of recurrence, though it is considered relatively low. Recurrence rates have been reported to be around 5% to 10% in some studies, while others suggest it can be up to 24% to 40% if the entire lesion is not completely excised during the initial surgery. Most recurrences, if they occur, happen within 1 to 4 months following the initial surgery. Regular follow-up care with a healthcare provider is important to monitor for any signs of recurrence and ensure complete healing.