Dermatofibrosarcoma protuberans (DFSP) [2] is a rare locally aggressive malignant cutaneous soft-tissue sarcoma. DFSP develops in the connective tissue cells in the middle layer of the skin (dermis).[3] Estimates of the overall occurrence of DFSP in the United States are 0.8 to 4.5 cases per million persons per year.[4][5] In the United States, DFSP accounts for between 1 and 6 percent of all soft tissue sarcomas [6] and 18 percent of all cutaneous soft tissue sarcomas. In the Surveillance, Epidemiology and End Results (SEER) tumor registry from 1992 through 2004, DFSP was second only to Kaposi sarcoma.
Variants[edit]
The World Health Organization, 2020, classified the fibrosarcomatous DFSP (DFSP-FS) variant (also termed dermatofibroma protuberans, fibrosarcomatous) of the dermatofibrosarcoma protuberans as a specific form of the intermediate (rarely metastasizing) fibroblastic and myofibroblastic tumors and other variants of this disorder as a specific form of the intermediate (locally aggressive) fibroblastic and myofibroblastic tumors.[8]
Bednar tumors[9][edit]
Bednar, or pigmented DFSP, is distinguished by the dispersal of melanin-rich dendritic cells of the skin. It represents 1-5 percent[10] of all DFSP occurring in people with rich in melanin pigments. Bednar characterized by a dermal spindle cell proliferation like DFSP but distinguished by the additional presence of melanocytic dendritic cells. It occurs at the same rate of DFSP on fairer skin and should be considered to have the same chances of metastasis.
Myxoid DFSP[11][edit]
Myxoid DFSP, which has areas of myxoid degeneration in the stroma[12]
Pathophysiology[edit]
More than 90% of DFSP tumors have the chromosomal translocation t(17;22). The translocation fuses the collagen gene (COL1A1) with the platelet-derived growth factor (PDGF) 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 a 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 it creates a self-stimulatory growth signal. The cell divides rapidly and tumor forms.
The tissue is often positive for CD34.[18][19]
Radiation therapy[edit]
DFSP is a radioresponsive tumor, radiation therapy (RT) is not used as the first choice for treatment. Conservative resection through MMS or WLE is attempted first. If clear margins are not achieved RT, or Chemotherapy is recommended.[29]
Chemotherapy[edit]
DFSP was previously regarded and nonresponsive to standard chemotherapy.[30] In 2006 the US FDA approved (imatinib mesylate) for the treatment of DFSP.[31] As is true for all medicinal drugs that have a name that ends in "ib," imatinib is a small molecular pathway inhibitor; imatinib inhibits tyrosine kinase. It may be able to induce tumor regression in patients with recurrent DFSP, unresectable DFSP, or metastatic DFSP.[32] There is clinical evidence that imatinib, which inhibits PDGF-receptors, may be effective for tumors positive for the t(17;22) translocation. It is suggested that imatinib may be a treatment for challenging, locally advanced disease and in the rare metastatic cases It was approved for use by adult patients with unresectable, recurrent and/or metastatic dermatofibrosarcoma protuberans (DFSP).[33]
Metastases to regional lymph nodes are extremely rare.[34] Distant hematogenous metastases are even rarer and are most likely in patients who have had multiple local recurrences after inadequate surgical resection.[35] Repeatedly recurring tumors have an increased risk for transformation into a more malignant form (DFSP-FS). The lungs are most frequently affected, but metastases to the brain,[36] bone,[37] and other soft tissues are reported.
Taylor, RW, in 1890.[38] first identified DFSP as a keloid sarcoma. Later in 1924, Darier, J and Ferrand, identified it as a progressive recurrent dermatofibroma. In 1925 it was E Hoffmann[39] who coined the term Dermatofibrosarcoma protuberans. Bednar tumor, first described by Bednar in 1957 [40][41]
https://en.wikipedia.org/wiki/Dermatofibrosarcoma_protuberans
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