Excerpt from Dermatofibrosarcoma Protuberans

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Background

Dermatofibrosarcoma protuberans (DFSP) is a relatively uncommon soft tissue neoplasm with intermediate-to-low grade malignancy. Although metastasis rarely occurs, DFSP is a locally aggressive tumor with a high recurrence rate.

Although DFSP may have been reported in the literature as early as 1890, Darier and Ferrand first described it in 1924 as a distinct cutaneous disease entity called progressive and recurring dermatofibroma. Hoffman officially coined the term dermatofibrosarcoma protuberans in 1925.

Pathophysiology

DFSP is a cutaneous malignancy that arises from the dermis and invades deeper subcutaneous tissue (eg, fat, fascia, muscle, bone).

The cellular origin of DFSP is not clear at this time. Evidence exists that supports the cellular origin being fibroblastic, histiocytic, or neuroectodermal.

Cultured DFSP tumor cells have increased growth response to platelet-derived growth factor (PDGF)–B. Cytogenetic studies may reveal specific lesions in DFSP tumor cells, such as reciprocal translocations of chromosomes 17 and 22, t(17;22), and supernumerary ring chromosomes composed of interspersed sequences from bands 17(17q22) and 22(22q12). These rearrangements fuse the collagen type I alpha 1 (COL1A1) and the PDGF-B chain (PDGFB, c-sis proto-oncogene) genes. The collagen promoter drives COL1A1 and PDGFB fusion protein production. The fusion protein is then processed into functional PDGF-B and subsequently interacts with PDGF receptor on the cell surface of DFSP tumor cells. The activation of the PDGF receptor tyrosine kinase triggers the proliferation of DFSP tumor cells.

Frequency

United States

DFSP accounts for less than 0.1% of all malignant neoplasms and approximately 1% of all soft tissue sarcomas. The incidence has been estimated to be 0.8-5 cases per million population per year in 2 separate studies. In a most recent study based on data from 9 cancer registries from 1973-2002, the annual incidence of DFSP in the United States is 4.2 per million cases per year.¹

International

The annual incidence of DFSP is reported as 3 cases per million population from a population-based cancer registry from 1982-2002 in France.²

Mortality/Morbidity

DFSP is a locally aggressive tumor with a high recurrence rate. Although metastasis of DFSP is rare (only 1-4% reported), almost all metastatic cases have been associated with local recurrence and a poor prognosis. Most of the patients with metastatic DFSP have died within 2 years.

A small subset of DFSP patients presents with fibrosarcomatous progression. This fibrosarcomatous progression DFSP variant is more aggressive in nature and the clinical outcome usually is poor.

Race

DFSP has been reported in persons of all races, and no racial predilection seems to exist in the previous reports. However, a recent study conducted by Criscione and Weinstock¹ found the incidence among blacks (6.5 cases per million population) was almost double the incidence among whites (3.9 cases per million population). An uncommon pigmented variant of DFSP, called the Bednar tumor, is found predominantly in black patients.

Sex

Several studies reveal an almost equal sexual distribution or a slight male predominance. In a large study³ of 902 patients with DFSP conducted by Rutgers et al, 514 (57%) patients were male and 388 (43%) patients were female.

Age

DFSP usually occurs in adults aged 20-50 years. Rarely, DFSP has been reported in newborns and elderly individuals (80 y).

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