Dermatofibrosarcoma protuberans (DFSP): symptoms, causes, diagnosis and treatment

Dermatofibrosarcoma protuberans is a rare tumour that starts in the deeper layer of the skin. BAD says it begins in the dermis and can spread locally to surrounding structures such as fat and muscle. Sarcoma UK adds that it may involve the fatty layer beneath, the subcutis, and, rarely, nearby muscle and connective tissue.

The Primary Care Dermatology Society (PCDS), writing for GPs, calls it a rare, locally invasive, slow-growing tumour that recurs frequently after surgical excision. It regards DFSP as a low-grade tumour, but notes that careful histological evaluation is needed because a small proportion of lesions develop a high-grade fibrosarcomatous component.

It is classed as a sarcoma, which is why sarcoma specialists are involved in treatment alongside skin cancer teams.

BAD describes DFSP as usually a slow-growing, painless, thickened lumpy area of skin that can be skin-coloured, pink or red, brown or black, or occasionally blue or purple, and that can feel like a soft or hardened sunken area. Most people have no symptoms, though they may notice thick skin, skin changing colour, a sunken area or a lump increasing in size. If left for several years, it can grow through the top layer of skin and produce an ulcer.

Sarcoma UK lists a slow-growing and often painless lump under the skin, a scar or deep-seated pimple that may crack open or bleed, and skin that may look like a bruise. It says DFSP can occur anywhere but most often in the torso, and also in the arms, legs, head and neck.

It tends to affect young to middle-aged adults, according to both BAD (early adult life) and Sarcoma UK (20 to 50 years, with a median age at diagnosis of 44), though it can occur at any age. BAD says it is not hereditary.

BAD says DFSP is treated by surgical excision and describes two main types of surgery. PCDS says management is in secondary care, with wide local excision of between 2 and 4 cm, or Mohs micrographic surgery.

BAD says most people only need surgery. If DFSP cannot be completely removed, or comes back or spreads, radiotherapy or targeted treatments may be used; Sarcoma UK names imatinib, a tablet, as a targeted therapy sometimes used. BAD adds that Mohs surgery may not be available in all UK regions because it requires a specialist.

BAD says that because DFSP is rare it may take time to diagnose, and that if it is suspected, a piece of abnormal skin is removed under local anaesthetic (a biopsy) and examined for specific features of the disease. Sarcoma UK describes physical examination, a skin biopsy and, where needed, scans such as MRI.

BAD says most people only need surgery, but if there are concerns that it may have spread, X-rays, ultrasound, MRI or CT scans may be needed.

Sarcoma UK says that if you are diagnosed with DFSP you should be referred to a specialist sarcoma multidisciplinary team, and seen by skin cancer specialists, dermatologists and plastic surgeons who can offer specialised treatments such as Mohs surgery, with a formal relationship between the sarcoma and skin cancer teams.

BAD says yes, DFSP can be completely treated in most people. In about 99 in 100 cases it can be completely removed with surgery. It is still possible for it to come back in the same place even if it was completely removed; if that happens, more treatment such as radiotherapy or targeted oral treatment may be needed.

In most people DFSP does not spread to other parts of the body such as the lungs and bones. BAD says this happens in about 1 in every 100 people with the condition, and that if it does spread it may not be possible to remove it. Sarcoma UK says DFSP tends to grow slowly and very rarely spreads, but without the correct treatment it can grow deep into fat, muscle and bone, which makes it more difficult to treat.

BAD says you will usually be asked to come back to the dermatology clinic for at least 5 years so doctors can check it has not returned. After treatment, check your scar at home, and contact your healthcare team if new lumps do not go back to normal within a week or two.

Because DFSP is slow growing and painless it is easy to ignore. BAD says that after treatment you should check the scar at home, and the same attitude applies beforehand: a skin lump, thickened patch or scar-like area that is growing, changing colour, ulcerating or bleeding should be looked at by a GP.

A GP may refer you to a dermatology service, and if a sarcoma is suspected, to a specialist team. A skin change that grows or looks different over weeks to months is a reason to be seen promptly. Sudden severe symptoms such as heavy bleeding or a rapidly spreading red, hot, painful area are a reason to use urgent care.

In the NHS, Sarcoma UK says people with DFSP should be referred to a specialist sarcoma multidisciplinary team and also seen by skin cancer specialists, dermatologists and plastic surgeons, who can offer specialised treatments such as Mohs surgery.

Private dermatology or plastic surgery is sometimes used for faster assessment or surgery. Given the need for biopsy confirmation and careful margin control, the same multidisciplinary standards should apply.