Dermatofibrosarcoma protuberans (DFSP)
is a rare neoplasm
of the dermis
layer of the skin, and is classified as a sarcoma
. In many respects, the disease behaves as a benign tumor
, but in 2-5% of cases it can metastasize
, so it should be considered to have malignant
Over 95% of DFSP tumors have the chromosomal translocation
t(17;22). The translocation fuses the collagen gene
) with the platelet-derived growth factor
gene. The fibroblast
, the cell
of origin of this tumor, expresses the fusion gene
in the belief that it codes for collagen. However the resulting fusion protein
is processed into mature platelet-derived growth factor
which is a potent growth factor
. Fibroblasts contain the receptor
for this growth factor. Thus the cell "thinks" it is producing a structural protein
, but in fact produces a self-stimulatory growth signal
. The cell divides
rapidly and a tumor forms.
Treatment is primarily surgical
, with chemotherapy
and radiation therapy
sometimes being used.
There is clinical evidence that imatinib, which inhibits PDGFB, may be effective for tumors positive for the t(17;22) translocation.
MOHS surgery can be extremely effective. It will remove the tumor and all related pathological cells without a wide-area excision that may overlook sarcoma cells that have penetrated muscle tissue.