Dermatofibrosarcoma protuberans (DFSP) is a rare malignant skin tumor associated with a characteristic chromosomal translocation (t[17;22][q22;q13]) resulting in theCOL1A1-platelet-derived growth factor β(PDGFB)fusion gene. This malignancy is rarely diagnosed in childhood.Objective
We observed an unexpected high incidence of this DFSP in children affected with adenosine deaminase–deficient severe combined immunodeficiency (ADA-SCID) and set out to evaluate the association of these 2 clinical entities.METHODS
Twelve patients with ADA-SCID were evaluated with a complete dermatologic examination and skin biopsy when indicated. Conventional cytogenetic and molecular analyses (fluorescencein situhybridization, RT-PCR, or both) were performed when possible.Results
Eight patients were found to have DFSP. Six patients had multicentric involvement (4-15 lesions), primarily of the trunk and extremities. Most lesions presented as 2- to 15-mm, round atrophic plaques. Nodular lesions were present in 3 patients. In all cases CD34 expression was diffusely positive, and diagnosis was confirmed either by means of cytogenetic analysis, molecular testing, or both. The characteristic DFSP-associated translocation, t(17;22)(q22;q13), was identified in 6 patients; results of fluorescencein situhybridization were positive for fusion of theCOL1A1andPDGFBloci in 7 patients; and RT-PCR showed theCOL1A1-PDGFBfusion transcript in 6 patients.Conclusions
We describe a previously unrecognized association between ADA-SCID and DFSP with unique features, such as multicentricity and occurrence in early age. We hypothesize that the t(17;22)(q22;q13) translocation that results in dermal overexpression ofPDGFBand favors the development of fibrotic tumors might arise because of the known DNA repair defect in patients with ADA-SCID. Although the natural course of DFSP in the setting of ADA-SCID is unknown, this observation should prompt regular screening for DFSP in patients with ADA-SCID.