summary Dermatofibrosarcoma Protuberans are rare, low-grade fibrogenic cutaneous sarcomas that occur in early to mid-adult life. Diagnosis is made with a biopsy showing uniform fibroblasts arranged in storiform pattern around an inconspicuous vasculature. Treatment is usually wide surgical resection with radiation therapy. Epidemiology Incidence accounts for 1% of soft tissue sarcomas Demographics slightly more common in males usually presents in people aged 20-50 years old more common in African Americans (2:1) vs. Caucasians Anatomic location trunk > proximal extremities > head/neck Etiology Variants Bednar tumor pigmented variant that is 7.5x more common in African Americans fibrosarcomatous more aggressive variant with poor prognosis Genetics mutations associated with t(17;22) encodes for PDGF-beta chain (PDGFB)/collagen type I alpha 1 (COL1A1) fusion protein Symptoms Presentation usually an slowly enlarging painless mass composed of firm irregular nodules may have dark red or blue discoloration Imaging Radiographs views CXR indications screen for pulmonary metastasis in high-risk cases (i.e. recurrence or suspicion for a fibrosarcoma variant of DFSP) CT indications suspected direct bone involvement or metastasis MRI indications preoperative assessment in larger or atypical lesions and recurrent disease Ultrasound indications monitoring of local DFSP or regional lymph node metastasis PET indications monitoring of metastatic disease Histology Biopsy is required for diagnosis Histology classically appears as uniform fibroblasts arranged in storiform pattern around an inconspicuous vasculature Bednar variant has scattered melanin-containing dendritic cells fibrosarcomatous variant has a characteristic herringbone pattern Treatment Nonoperative imatinib inhibits PDGF-receptor tyrosine kinase indications adult patients with unresectable, recurrent, and/or metastatic DFSP outcomes 65% response rate no response in patients who lack the t(17,22) mutation Operative wide surgical resection +/- adjuvant radiation therapy indications patients with resectable DFSP adjuvant radiation therapy is useful in patients with positive margins or in whom adequate wide excision alone may result in major cosmetic or functional deficits technique clean margins are an important goal of surgical resection obtain 2-3cm margins dissect deep to and excise all tissue including the fascia total dose of radiation therapy is 50-70 Gy outcomes 15.7% recurrence for lesions on the body 51.8% recurrence rate for lesions on the head/neck LocationXrayXrayCTB. ScanMRIMRIHisto(1)Case Atibia Prognosis Local recurrence is common Distant metastasis is rare (< 5%) lung is the most common site of distant metastasis occurs via hematogenous spread usually preceded by multiple local recurrences Worse prognosis seen with regional lymph node involvement fibrosarcomatous progression DFSP variant histologic features: high number of mitotic figures, increased cellularity, DNA aneuploidy, TP53 gene overexpression, and the presence of fibrosarcomatous changes age > 50 years old