What Is Dermatofibrosarcoma Protuberans? Symptoms and Treatment

What Is Dermatofibrosarcoma Protuberans?

• Dermatofibrosarcoma protuberans is a rare sarcoma of the tissue beneath the skin (a soft tissue tumour). These tumours appear as skin masses, or deep nodules.
• They generally grow slowly and may be present for years before becoming clearly noticeable. They are usually painless.
• Dermatofibrosarcoma protuberans is considered a low-grade tumour, meaning it very rarely metastasises. It can also recur after surgery. Close medical follow-up is therefore important and recommended.
• Mohs micrographic surgery is a standard treatment option. A fairly wide surgical removal is performed. With appropriate treatment, the disease course is generally uncomplicated.

What Other Names Are Used?

• Darier–Ferrand tumour
• Darier–Hoffmann tumour
• DFSP (dermatofibrosarcoma protuberans)

Age and Sex Distribution of Dermatofibrosarcoma Protuberans

• Dermatofibrosarcoma protuberans generally occurs in young and middle-aged adults.
• Both men and women are affected, although it is more common in men.
• People of all racial and ethnic backgrounds may be affected. No particular geographical concentration of dermatofibrosarcoma protuberans has been reported worldwide.

Which Factors Increase the Risk of Dermatofibrosarcoma Protuberans?

No definite risk factor for developing dermatofibrosarcoma protuberans has currently been reported. However, the tumour has been associated with:

• Previously traumatised tissue
• Areas of extensive burns
• Surgical incision sites
• Vaccination sites (BCG vaccination)
• Arsenic poisoning

Further studies to understand the risk factors are ongoing.

Having a risk factor does not mean a person will develop the condition. It increases the likelihood compared with someone without risk factors. Some risk factors are more important than others.

Likewise, the absence of a risk factor does not mean a person will not develop the condition. Discussing the effects of risk factors with your doctor is always important.

What Causes Dermatofibrosarcoma Protuberans? (Aetiology)

• The exact cause of dermatofibroma protuberans is unknown.
• Certain genetic mutations have sometimes been reported, but they remain under investigation.

What Are the Symptoms of Dermatofibrosarcoma Protuberans?

The clinical signs and symptoms of dermatofibroma protuberans include:

• A usually slow-growing, nodular, painless mass beneath the skin
• The skin over the mass is generally reddish-brown, without ulceration of the overlying skin.
• As tumours grow and develop, the skin above them may ulcerate and become infected.
• The mass generally develops in the head and neck, chest, abdominal wall or back. It rarely occurs in the arms and legs.
• Occasional case reports have described tumours in the salivary gland (parotid gland) and genital region.

How Is Dermatofibrosarcoma Protuberans Diagnosed?

Diagnosis may involve:

• A comprehensive medical history and physical examination
• Dermoscopy: a diagnostic tool in which a dermatologist examines the skin with a special magnifying lens.
• Tissue biopsy of the tumour: a tissue sample is taken and sent to a laboratory for pathological examination. A pathologist’s microscopic examination of the biopsy is considered the gold standard for a definitive diagnosis.

The pathologist reaches a definitive diagnosis by combining clinical and microscopic findings. Special investigations may sometimes include immunohistochemical stains, molecular tests and, very rarely, electron microscopy. Pathological examination is central to a definitive diagnosis of dermatofibrosarcoma protuberans.

The pathologist may need to distinguish this tumour from similar tumours, such as dermatofibroma. A differential diagnosis is often considered to exclude other tumour types before reaching the final diagnosis.

Many clinical conditions can cause similar signs and symptoms. Your doctor may perform additional tests to exclude other conditions and establish a definitive diagnosis.

What Complications Can Dermatofibrosarcoma Protuberans Cause?

Possible complications of dermatofibrosarcoma protuberans (DFSP) include:

• If not treated promptly, the tumour may spread locally into other tissues.
• Tumour recurrence after surgery
• If DFSP recurs after inadequate surgery, it may metastasise to the lungs.

How Is Dermatofibrosarcoma Protuberans Treated?

The essential treatment for dermatofibrosarcoma protuberans (DFSP) is surgical excision.

• Wide excision is the preferred treatment. It may be performed with 5 cm margins down to the fascia, removing all skin and subcutaneous fat. Mohs micrographic surgery is widely used and provides microscopic margin control during the procedure.
• Incomplete surgery often results in recurrence, usually detected within the first five years after surgery.
• Surgical defects are generally large. Patients require well-planned reconstruction or a period of healing.
• Imatinib is FDA-approved for unresectable, recurrent or metastatic DFSP.

Can Dermatofibrosarcoma Protuberans Be Prevented?

There is currently no way to prevent the onset of dermatofibrosarcoma protuberans, a rare low-grade tumour.

What Is the Prognosis of Dermatofibrosarcoma Protuberans? (Outcomes)

• Dermatofibrosarcoma protuberans is a low-grade sarcoma requiring complete surgical removal. Prognosis is generally excellent after complete excision.
• Incomplete removal results in recurrence, generally within 5 years of the initial operation.
• Careful follow-up with periodic medical examinations is necessary.

Additional Useful Information About Dermatofibrosarcoma Protuberans

• Various immunostains can help establish a definitive diagnosis. Dermatofibrosarcoma protuberans is usually positive for CD34 and vimentin.
• A common tumour called dermatofibroma may resemble dermatofibrosarcoma protuberans, making careful examination necessary. Dermatofibrosarcoma protuberans is negative for S-100, epithelial membrane antigen, smooth muscle actin and desmin. This staining pattern helps distinguish it from dermatofibroma.