Dermatofibrosarcoma protuberans (DFSP) is a rare tumor affecting the deep layers of the skin.
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Incidence
DFSP can occur at any age, including the newborn period, but it is most commonly found in individuals between the ages of 20 and 50. Women have a slightly higher incidence, and it grows faster than usual during pregnancy. In newborns, it may be mistaken for a birthmark.
The incidence of DSFP among blacks is approximately twice the incidence that has been observed in whites. However, the incidence in the latter group is rising, especially among white residents of Hawaii.
Causes
The risk factors for this tumor are yet to be identified, but some cases have been noted to arise in skin that was previously burned or suffered severe trauma.
The underlying etiology of DSFP appears to be genetic, with the translocation t17;22 being found in 90% of all patients affected. This mutation is commonly found as a supernumerary ring chromosome carrying parts of the genes COL1A1 and PDGFB, from chromosome 17 and 22 respectively, in fused form.
While COL1A1 is responsible for the production of collagen type 1, providing support and structural strength to many tissues, the other is a powerful growth factor that enables many cells to grow, proliferate and differentiate. The fused gene results in the production of large amounts of PDGFB, which promotes the proliferation of the mutated clone of cells to form a DFSP tumor.
Dermatofibrosarcoma Protuberans (DFSP) Explained by Mayo Clinic
Clinical features
The general lack of symptoms in DfSP causes the diagnosis of this disease to often occur well after tumor development begins in most patients. In fact, it is estimated that less than a fifth of all DSFP patients report pain or redness.
The first sign of DFSP is a soft to firm skin patch that slightly changes over the months or years in most cases. It is flesh-colored, reddish or purple, and either flat, raised, or even depressed, in some patients. Some reports state that this skin patch can resemble a pimple, a scar or a birthmark.
The margins of DSFP tumors are irregular in many cases. It has a somewhat shiny surface, but it is hardly ever associated with pain or tenderness until the late stages. DSFP tumors tend to be locally aggressive but not metastatic.
After several years, the tumor may start to grow more aggressively, swell or become painful, or bleed. Additional tumors may appear in the nearby the original one. The color of these tumors may change to blackish or brownish, at which point the tumors will grow faster than before.
In the early stages of DFSP, the tumor has three forms:
- A morphea-like form that closely resembles a scar or plaque
- An atrophoderma-like form
- An angioma-like form
The size of a typical DSFP tumor ranges from 1-25 centimeters (cm), although most are less than 5 cm wide. DSFP tumors are typically present over the torso (50-60%), extremities (35%), or the head and neck region (10-15%); however, no part of the skin is exempt. In fact, DFSP has even been reported in the vulva, breast or scalp.
The DSFP lesion is usually first noticed when it starts to grow rapidly,or becomes more prominent. At this point, the growing tumor pushes up against the superficial skin to form a firm or rubbery patch, over which the skin is stretched and may become tender, ulcerate, bleed, or feel fixed to the tumor.
The tumor may also enter a rapid growth phase during pregnancy.
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