Dermatofibrosarcoma protuberans

Synonyms: DFSP

By Dr. Pascal Bafteh · last updated 09/2026

Definition & Epidemiology

• Most common sarcoma of the skin, fibroblastic differentiation with (myo-)fibroblastic components.
• Average age: ~ 40 years, slow destructive local growth.
• Metastasis rare: < 5 % hematogenous pulmonary.

Genetics & Pathogenesis

• Characteristic translocation: [t COL1A1-PDGFB|t EWSR1-FLI1|BRAF-V600E|MYCN amplification] in > 90 % → constitutive activation of the PDGF-β receptor signaling pathway → molecular target forImatinib.
• Sporadic, no known heritability.

Clinical Presentation

• Location: trunk-predominant (~ 50 %), proximal extremities, shoulders; rarely head and neck.
• Appearance: brownish-livid plaque.
• Course: Years of unremarkable plaque-stage progression until nodular manifestation; destructive-infiltrative, R0 resection technically challenging due to tentacular subcutaneous extensions.

Sub-Variants

• Classic DFSP — as above.
• Bednar tumor (pigmented DFSP variant): melanin-containing dendritic cells.
• Fibrosarcomatous DFSP transformation (DFSP-FS): Dedifferentiation + Mitosis ↑.
• Giant cell fibroblastoma: pediatric variant, same COL1A1-PDGFB translocation.

Diagnostics

• Clinical presentation + ultrasound of the primary tumor (depth of extension, hypoechoic-heterogeneous).
• MRI in case of suspected deep infiltration (subcutis, fascia).
• Punch or incisional biopsy: Histology shows monomorphic spindle cell proliferation in a storiform pattern, subcutaneous infiltration as a "honeycomb pattern".
• Immunohistochemistry: CD34+ + CD99+, F XIIIa− for differentiation from dermatofibroma (= XIIIa+).
• Molecular: FISH or RT-PCR for COL1A1-PDGFB fusion to confirm difficult cases (e.g., fibrosarcomatous variant).
• Staging: Whole-body examination + ultrasound of regional lymph nodes; for DFSP-FS, additionally CT thorax (metastases rare, but mandatory).

Differential diagnoses

• Dermatofibroma
• Lipoma
• Epidermal cyst (atheroma)
• Basal cell carcinoma
• Melanoma
• Cutaneous angiosarcoma
• Kaposi's sarcoma

Sources (selection)

1. Saiag 2015 EADO DFSP

More skin tumours

• Basal cell carcinoma
• Melanoma
• Lentigo maligna
• Cutaneous squamous cell carcinoma
• Actinic keratosis
• Actinic cheilitis
• Merkel cell carcinoma
• Microcystic adnexal carcinoma

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.